Vitamin D Deficiency – Symptoms, Treatment and Causes

The following article was selected as the winner for Fitness Savvy’s 2019 Scholarship Award.

This submission was received from Ashwin Venkatakishnan, who is studying Medicine.

Vitamin D Deficiency – Symptoms, Treatment and Causes

Vitamins are organic compounds that are essential for humans. There are 13 types of vitamins in total.1 In this article, we will focus on what constitutes Vitamin D deficiency and examine its symptoms, treatments and causes.

Vitamin D is a hormone, meaning that it binds to specific receptors (Vitamin D Receptors – VDRs) to have an effect on the body. It exists naturally as either Vitamin D2 or Vitamin D3. Vitamin D2 is produced by plants and mushrooms while Vitamin D3 is found in animal-sourced foods such as fatty fish and eggs. Interestingly, our own skin also produces Vitamin D3 when exposed to ultraviolet radiation from sunlight.2

Both forms first undergo hydroxylation in the liver to form 25-hydroxyvitamin D [25(OH)D] before being further hydroxylated in the kidney to form the biologically active 1,25-hydroxyvitamin D [1,25(OH)2D]. 25(OH)D has a half-life of 15 days. This means that the time taken for its concentration to reduce to half its original level is 15 days. In contrast, 1,25(OH)2D has a half-life of just 15 hours. As such, serum concentration of the former serves as the better long-term indicator of the amount of Vitamin D in our bodies. This concentration is measured in ng/ml or nmol/l, with 1 ng/ml roughly equal to 2.5 nmol/l. Take note that this conversion is only for Vitamin D!

Vitamin D Intake and Metabolism

Members of the medical community are divided over what is the optimum serum level, ranging from 12 ng/ml to 40 ng/ml.3 However, the consensus is that Vitamin D deficiency occurs when the 25(OH)D level is less than 20ng/ml and one should strive to maintain a level of around 30ng/ml.4 Vitamin D deficiency has many side effects as listed and explained below.

  1. Impaired Immune System – Our body has 2 main types of immune responses, namely innate (nonspecific) and adaptive (antigen-specific). Vitamin D is helpful in both. It increases production of many antimicrobials and enhances the function of our existing macrophages and neutrophils. These are large white blood cells which ‘eat’ foreign matter indiscriminately. In addition, Vitamin D activates specialised immune defence cells like T-cells and is thought to help prevent tissue damage by limiting the inflammatory response of our immune system. Lack of Vitamin D can compromise our immune system, making us more susceptible to pathogens.5

Effect Vitamin D Immune System

  1. Bone Weaknesses and Disorders – Vitamin D promotes the absorption of calcium and phosphorous in our intestines which keeps our bones strong and healthy. When there is too little Vitamin D, there is less calcium uptake and this can result in osteoporosis, where the patient is afflicted with thin, brittle bones.6

In addition, Vitamin D helps correct hypocalcaemia (low blood calcium level) and hypophosphatemia (low blood phosphorous level) by stimulating bone resorption (breaking down of bone) to release calcium and phosphorous into the blood. When Vitamin D is deficient, an alternate homeostatic pathway occurs. More parathyroid hormone (PTH) is synthesised which helps correct hypocalcaemia but worsens hypophosphatemia by enhancing urinary phosphate excretion. This leads to even greater bone resorption7 and can cause osteomalacia, a condition, where the bones become soft and more prone to fracture, increasing both the initiation and propagation of cracks in bones by up to 31%.8Healthy Bones vs Rickets Vitamin D

Osteomalacia in adults has less obvious symptoms which disappear once treated. When it occurs in children, it is called rickets and has more severe symptoms. In addition to obvious skeletal deformities such as an oddly shaped skull and a curved spine, stunted growth and muscle cramps have been observed in rickets-afflicted children.9Vitamin D Alopecia

  1. Hair Loss – Vitamin D plays an important role in creating new hair follicles. New follicles not only help maintain hair thickness, but also prevent the premature fall of existing hair.10 Vitamin D deficiency can cause hair loss and has been linked with alopecia areata.11 This is an autoimmune disease in which the immune system mistakenly attacks the body’s own hair follicles, causing hair on the scalp to fall out in patches. Hair on other parts of the body is also susceptible.12
  2. Muscle Pain – Pain-sensing nerve cells called nociceptors contain these specific Vitamin D receptors (VDRs). Vitamin D binds to these VDRs and inhibits the growing of these nerves into muscle fibres (innervation). Vitamin D deficiency leads to hyperinnervation by nociceptors, inducing musculoskeletal pain. 13
  3. Blood Sugar Issues – Beta cells in the pancreas produce the hormone insulin that allows our body to make use of the sugars in the food we eat. It Vitamin D and Type 2 Diabetesdirects the absorption of sugars from our blood into our cells where the sugars are either broken down to produce energy or stored in the form of glucose for future use. Vitamin D deficiency can lead to decreased sensitivity to insulin. Insulin is now less effective in regulating blood sugar levels and this can lead to Type II Diabetes. 14
  4. Depression – Vitamin D is thought to also affect our emotional well-being. VDRs exist in several regions in our brain and are particularly abundant in the hypothalamus, which is in charge of regulating emotional reVitamin D and Depressionsponses.15 Vitamin D deficiency has been linked to depression, though whether it causes depression remains to be rigorously proven.16Vitamin D deficiency is not to be taken lightly. One requires approximately 2200-3000 IU (International Units) of vitamin D per day, obtained from all sources including sunlight, to maintain a 25(OH)D level of 30-32 ng/ml.17In 1972, 1 IU of Vitamin D was formally defined as having the same amount of biological activity as 65 pmol of Vitamin D2 or D3 which translates to approximately 25.78 ng of the former or 25 ng of the latter.18 Vitamin D2 vs Vitamin D3However, recent studies have shown Vitamin D3 to have much higher potency than Vitamin D219,20. 50,000 IU of Vitamin D2 is equivalent to 5,000-15,000 IU of Vitamin D3 and not 50,000 IU of Vitamin D3 as previously thought.19

Vitamin D2 vs D3 biological activity

The recommended dietary allowance (RDA) of Vitamin D from foods alone is 600 IU/day for youths and adults and 800 IU/day for those aged above 70 years.4 Vitamin D deficient people need to consume way more in order to raise their 25(OH)D level to at least 30ng/ml in the short term. One can increase his Vitamin D intake through the following ways.

  1. Eat Vitamin D-rich foods – Vitamin D is fat-soluble, meaning it is absorbed best when taken with higher-fat foods. Fatty fish like salmon and herrings provide up to 1600 IU of Vitamin D per serving.21

Cod liver oil can also be taken. One teaspoon alone provides 450 IU of vitamin D. Besides, it is rich in multiple essential nutrients, making it an excellent choice all round. The only problem (other than its taste!) is a problem of plenty. Just one teaspoon contains 90% of the RDA for vitamin A. When too much vitamin A is taken in, one can suffer symptoms ranging from drowsiness to nausea and respiratory infection.22

People who don’t eat seafood can consider egg yolks and mushrooms. Egg yolks from chickens raised indoors contain less than 40 IU, while those from chickens free to roam outdoors have up to 160 IU of vitamin D. However, they pale in comparison to egg yolks from chickens given Vitamin D enriched food, which have up to 6000 IU! Mushrooms grown in the wild or under UV light have up to 2300 IU per serving and 130-450 IU per serving respectively.21

Since natural sources of food are hard to come by, several common food items have been fortified with Vitamin D. Examples include cow’s milk (130 IU per cup), soy milk (99-119 IU per cup), orange juice (142 IU per cup) and some cereal and oatmeal (55-154 IU per ½ cup serving).21

Vitamin D Foods and Sources

To increase the 25(OH)D level by a large amount quickly, one would be better served by the following method.

  1. Take Vitamin D supplements – Capsules come in various dosages, ranging from 400 IU all the way to a maximum of 50,000 IU (prescription only). The patient’s 25(OH)D level is first checked before deciding the dosage. The prescribed capsules usually have to be taken either daily or weekly.

Recommended VItamin D Supplement Doses

There are two important things to take note. Firstly, supplements do not straightaway raise the 25(OH)D level. Secondly different patients respond in different ways to the same dosage. One factor affecting the patient’s response is his BMI. Since Vitamin D is fat-soluble, it tends to get absorbed by fatty tissue. A rule of thumb is that every 1000 IU of vitamin D3 taken daily will raise a 25(OH)D level of a healthy person by 10 ng/ml in a few weeks’ time. Obese people have to take in more Vitamin D to raise their serum level by the same amount and are thus prescribed higher doses.23

The patient has to recheck his vitamin D level around 3 months after starting treatment to ensure he is on the right track. Even if the patient’s 25(OH)D level has become optimal, he will need to continue taking supplements, albeit of a lower dose, to maintain his 25(OH)D level.

Certainly, taking Vitamin D supplements to raise the 25(OH)D level seems more appealing than eating the same few foods over and over again. Supplements are also cheap, with an entire bottle of capsules priced in the vicinity of $20.

The only real disadvantage that supplements have is that there is a risk of vitamin D toxicity (25(OH)D level above 150 ng/ml).17 Such high levels can only be achieved if patients take their high dose capsules daily when they were supposed to take them weekly instead. This is either the patient’s fault (misreading the prescription) or the medical practitioner’s fault (mislabelling the prescription). Possible vitamin D toxicity is one reason for patients needing to recheck their 25(OH)D level after 3 months of taking supplements.

Symptoms of vitamin D toxicity include hypercalcemia (elevated blood calcium levels), nausea, kidney failure and surprisingly, bone loss.24 Although Vitamin D is crucial for maintaining strong bones, excessive amounts are thought to drastically lower the level of Vitamin K2, another vitamin instrumental to bone health, leading to bone resorption.24 Fortunately, these problems are reversible if proper medical care is sought upon the appearance of symptoms.25

If you are put off by the risk of Vitamin D toxicity, you can consider the following method.

  1. Get more sunlight – There are three types of ultraviolet radiation in sunlight, namely UVA, UVB and UVC. As UVB rays hit cholesterol in our skin cells, Vitamin D3 is synthesized. Not only is this method completely free, but there is also absolutely no risk of Vitamin D toxicity, no matter how long one stays under the sun. UVB-induced Vitamin D production in skin is a self-limiting process, with sunlight degrading any excess Vitamin D produced.26

UVB rays have low penetrating power. They cannot pass through glass windows, so merely sitting in an office building next to a closed window will have no effect on Vitamin D production in the skin. They are also blocked by sunscreen so one has to go unprotected under the sun to maximise the speed of Vitamin D production.27 In addition, thick clothing hinders UVB rays, so wearing a thin t-shirt and shorts allows one to absorb more Vitamin D.28

This method is also quick-acting. A mere thirteen minutes of sunlight exposure in midday, three times a week during summer, is sufficient to maintain healthy levels among Caucasian adults in the UK!29 However, the recommended duration under the sun is much longer for people with dark skin as they have more melanin that reduces the amount of UVB rays absorbed. People living further from the equator also have to be outdoors longer as they get exposure to fewer UVB rays per unit time.30,31

Vitamin D Equator

Receiving just one mineral erythemal dose (lowest dose of UV light that causes slight reddening of the skin) was found to have the same effect on the 25(OH)D level as ingesting approximately 15,000 – 20,000 IU of Vitamin D in a single dose. The 25(OH)D level also remained elevated for a longer time.32 It is not recommended to stay unprotected under the sun longer than necessary as there is a possible risk of skin cancer. It is thus good to start seeking shelter once your skin starts to redden.

Vitamin D SunlampIf being exposed to the sun is not possible (during winter months for instance), one can get a light box, preferably one that can supply 10,000 lux of full spectrum light. Sitting in front of a box 30 minutes a day is sufficient. If symptoms such as eyestrain or headaches due to bright light occur, one can consider shifting further away from the light box or using it in shorter intervals instead.33 A light box is not cheap, with prices being as high as $1000, but note that this is a one-time investment that can be used for life.

It can now be understood how some cannot meet their minimum daily Vitamin D requirement without supplements. Vegans have limited Vitamin D-rich food choices. Obese people have to consume way more Vitamin D due to its tendency to get stored in fatty tissues instead of remaining in the blood. People having a 9-5 desk job or living far away from the equator are less likely to spend enough time under the sun. This also applies for those who regularly wear sunscreen or cover most of their skin outdoors. We will now examine 3 new causes of Vitamin D deficiency.

  1. Impaired Digestive System – Fat-digesting juices are needed to break down Vitamin D. Hence, disorders such as obstructive jaundice and cystic fibrosis,34 where there is low release of fat-digesting bile juices, are risk factors of Vitamin D deficiency. In addition, conditions like Coeliac Disease, Crohn’s Disease35 and gastric bypass drastically reduce absorption of nutrients like Vitamin D into the bloodstream. Therefore, even if sufficient Vitamin D is ingested into the body, the amount that actually makes it into the blood is ultimately insufficient.

    Vitamin D Coeliac Disease

    Vitamin D Crohn's Disease

    Vitamin D Gastric Bypass

  2. . Impaired Kidney and Liver – The liver and kidney are needed to metabolise the ingested Vitamin D into its biologically active form of 1,25(OH)2D. Any problem with these 2 organs will affect the synthesis of 1,25(OH)2D. Furthermore, kidney disorders involving proteinuria (excessive protein in urine) such as Nephrotic Syndrome and renal Fanconi Syndrome also play a role in Vitamin D deficiency. This is because one of the many proteins being wrongly excreted in the urine is Vitamin D-Binding Protein (VDBP). As VDBP is usually bound to Vitamin D, excretion of VDBP also means excretion of Vitamin D.36 Renal disorders involving tubules can be inherited, and some can result in major organs becoming resistant to 1,25(OH)2D.37VItamin D Nephrotic SyndromeVitamin D Fanconi Syndrome
  3. Usage of certain catabolism-promoting drugs – Drugs like glucocorticoids and anti-epileptic agents enhance the synthesis of hydroxylases that degrade 25(OH)D and 1,25(OH)2D, resulting in possible Vitamin D deficiency.38
  4. Old Age – As people age, their skin produces less Vitamin D when under the sun. Elderly people are also more likely to be homebound and get below-average exposure to sunlight. Since they get less Vitamin D through sunlight, they have to get more through food, which is why their RDA of Vitamin D is significantly higher than for other age groups. However, even if the elderly manage to consume enough Vitamin D, the combination of factors 1 and 2 naturally make them more vulnerable to Vitamin D deficiency due to their organs being more susceptible to failure.39

Major Causes Vitamin D DeficiencyIn conclusion, Vitamin D is crucial to humans as the multitude of symptoms arising from its deficiency would attest. There are numerous reasons for it to be lacking in humans but there are also numerous ways to correct the problem.

References

1 Nordqvist, Christian. “Vitamins: What Are They and What Do They Do?” Medical News Today, MediLexicon International, 26 Sept. 2017, www.medicalnewstoday.com/articles/195878.php.

2 Bordelon, Paula, et al. “Recognition and Management of Vitamin D Deficiency” American Family Physician. 80.8 (2009): 841. American Academy of Family Physicians. Web. 01 Mar. 2019.

3 Dawson-Hughes, Bess, et al. “Estimates of Optimal Vitamin D Status.” Osteoporosis International, vol. 16, no. 7, 2005, pp. 713–716., doi:10.1007/s00198-005-1867-7.

4 “Office of Dietary Supplements – Vitamin D.” NIH Office of Dietary Supplements, U.S. Department of Health and Human Services, 2018, ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/.

5 Schwalfenberg, Gerry K. “A Review of the Critical Role of Vitamin D in the Functioning of the Immune System and the Clinical Implications of Vitamin D Deficiency.” Molecular Nutrition & Food Research, vol. 55, no. 1, 2010, pp. 96–108., doi:10.1002/mnfr.201000174.

6 “Vitamin-D Deficiency Makes Bones Age Prematurely.” Healthline, Healthline Media, www.healthline.com/health-news/aging-vitamin-d-deficiency-ages-bones-prematurely-071013.

7 Sahay, Manisha, and Rakesh Sahay. “Rickets-Vitamin D Deficiency and Dependency.” Indian Journal of Endocrinology and Metabolism, vol. 16, no. 2, 2012, p. 164., doi:10.4103/2230-8210.93732.

8 Busse, Björn, et al. “Vitamin D Deficiency Induces Early Signs of Aging in Human Bone, Increasing the Risk of Fracture.” Science Translational Medicine, vol. 5, no. 193, 2013, doi:10.1126/scitranslmed.3006286.

9 Cafasso, Jacquelyn. “Rickets: Symptoms, Diagnosis, and Treatments.” Healthline, Healthline Media, 2017, www.healthline.com/health/rickets.

10 Fletcher, Jenna. “Vitamin D Deficiency Hair Loss: Symptoms and Treatment.” Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/321673.php.

11 Gade, Venkata Krishna Vamsi, et al. “An Investigation of Vitamin D Status in Alopecia Areata.” Clinical and Experimental Medicine, vol. 18, no. 4, 2018, pp. 577–584., doi:10.1007/s10238-018-0511-8.

12 Rivers, Autumn, and Jacquelyn Cafasso. “Alopecia Areata: Causes, Symptoms, and Diagnosis.” Healthline, Healthline Media, www.healthline.com/health/alopecia-areata.

13 Tague, S. E., et al. “Vitamin D Deficiency Promotes Skeletal Muscle Hypersensitivity and Sensory Hyperinnervation.” Journal of Neuroscience, vol. 31, no. 39, 2011, pp. 13728–13738., doi:10.1523/jneurosci.3637-11.2011.

14 “Vitamin D and Type II Diabetes.” Vitamin D Council, 2013, www.vitamindcouncil.org/health-conditions/type-ii-diabetes/#.XH9xdCgzZPa.

15 Eyles, Darryl W., et al. “Distribution of the Vitamin D Receptor and 1α-Hydroxylase in Human Brain.” Journal of Chemical Neuroanatomy, vol. 29, no. 1, 2005, pp. 21–30., doi:10.1016/j.jchemneu.2004.08.006.

16 Ju, Sang-Yhun, et al. “Serum 25-Hydroxyvitamin d Levels and the Risk of Depression: A Systematic Review and Meta-Analysis.” The Journal of Nutrition, Health & Aging, 2012, doi:10.1007/s12603-012-0426-0.

17 Khan, Qamar J., and Carol J. Fabian. “How I Treat Vitamin D Deficiency.” Journal of Oncology Practice, vol. 6, no. 2, 2010, pp. 97–101., doi:10.1200/jop.091087.

18 Norman, Anthony W. “Problems Relating to the Definition of an International Unit for Vitamin D and Its Metabolites.” The Journal of Nutrition, vol. 102, no. 10, 1972, pp. 1243–1246., doi:10.1093/jn/102.10.1243.

19 Armas, Laura A. G., et al. “Vitamin D2Is Much Less Effective than Vitamin D3in Humans.” The Journal of Clinical Endocrinology & Metabolism, vol. 89, no. 11, 2004, pp. 5387–5391., doi:10.1210/jc.2004-0360.

20 Bouillon, Roger, et al. “Is Vitamin D2Really Bioequivalent to Vitamin D3?” Endocrinology, vol. 157, no. 9, 2016, pp. 3384–3387., doi:10.1210/en.2016-1528.

21 Jones, Taylor. “9 Healthy Foods That Are High in Vitamin D.” Healthline, Healthline Media, 12 Sept. 2018, www.healthline.com/nutrition/9-foods-high-in-vitamin-d.

22 Pietrangelo, Ann. “Hypervitaminosis A: Causes, Symptoms, and Diagnosis.” Healthline, Healthline Media, 2017, www.healthline.com/health/hypervitaminosis-a.

23 Lee, Paul, et al. “Adequacy of Vitamin D Replacement in Severe Deficiency Is Dependent on Body Mass Index.” The American Journal of Medicine, vol. 122, no. 11, 2009, pp. 1056–1060., doi:10.1016/j.amjmed.2009.06.008.

24 Spritzler, Franziska. “6 Side Effects of Too Much Vitamin D.” Healthline, Healthline Media, 26 Feb. 2017, www.healthline.com/nutrition/vitamin-d-side-effects.

25 Araki, Takako, et al. “Vitamin D Intoxication with Severe Hypercalcemia Due to Manufacturing and Labeling Errors of Two Dietary Supplements Made in the United States.” The Journal of Clinical Endocrinology & Metabolism, vol. 96, no. 12, 2011, pp. 3603–3608., doi:10.1210/jc.2011-1443.

26 Mawer, E. Barbara, et al. “Vitamin D Metabolism in Patients Intoxicated with Ergocalciferol.” Clinical Science, vol. 68, no. 2, 1985, pp. 135–141., doi:10.1042/cs0680135.

27 Raman, Ryan. “How to Safely Get Vitamin D From The Sun.” Healthline, Healthline Media, 28 Apr. 2018, www.healthline.com/nutrition/vitamin-d-from-sun.

28 Dannie, Marie. “Can You Get Vitamin D Through a Light Shirt?” Healthy Eating | SF Gate, 17 Dec. 2018, healthyeating.sfgate.com/can-vitamin-d-through-light-shirt-10178.html.

29 Rhodes, Lesley E., et al. “Recommended Summer Sunlight Exposure Levels Can Produce Sufficient (≥20ngml−1) but Not the Proposed Optimal (≥32ngml−1) 25(OH)D Levels at UK Latitudes.” Journal of Investigative Dermatology, vol. 130, no. 5, 2010, pp. 1411–1418., doi:10.1038/jid.2009.417.

30 Braun, Perrin. “Vitamin D and Sun Exposure: How to Optimize Your Levels.” Vitamin D and Sun Exposure: How to Optimize Your Levels, 23 Apr. 2014, blog.insidetracker.com/vitamin-d-and-sun-exposure-how-to-optimize-your-levels.

31 “Chart of Vitamin D Levels vs Race – April 2013.” Chart of Vitamin D Levels vs Race – April 2013 |, 2016, vitamindwiki.com/Chart+of+Vitamin+D+levels+vs+race+-+April+2013.

32 Holick, Michael F. “Vitamin D: A D-Lightful Solution for Good Health.” Journal of Medical Biochemistry, vol. 31, no. 4, 2012, pp. 263–264., doi:10.2478/v10011-012-0031-z.

33 “Light Therapy.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 8 Feb. 2017, www.mayoclinic.org/tests-procedures/light-therapy/about/pac-20384604.

34 “Cystic Fibrosis and Liver Disease – Facts and Symptoms.” Cystic Fibrosis and Liver Disease – Facts and Symptoms, www.cysticfibrosis.org.uk/what-is-cystic-fibrosis/how-does-cystic-fibrosis-affect-the-body/symptoms-of-cystic-fibrosis/liver-disease.

35 Holland, Kimberly. “Crohn’s Disease: Treatment, Causes, Diagnosis, and More.” Healthline, Healthline Media, 2018, www.healthline.com/health/crohns-disease.

36 Thrailkill, Kathryn M., et al. “Enhanced Excretion of Vitamin D Binding Protein in Type 1 Diabetes: A Role in Vitamin D Deficiency?” The Journal of Clinical Endocrinology & Metabolism, vol. 96, no. 1, 2011, pp. 142–149., doi:10.1210/jc.2010-0980.

37 “Genetic Vitamin D Deficiency Information.” MyVMC, 24 May 2018, www.myvmc.com/diseases/inherited-vitamin-d-disorders/.

38 Gröber, Uwe, and Klaus Kisters. “Influence of Drugs on Vitamin D and Calcium Metabolism.” Dermato-Endocrinology, vol. 4, no. 2, 2012, pp. 158–166., doi:10.4161/derm.20731.

39 Maurya, Vaibhav Kumar, and Manjeet Aggarwal. “Factors Influencing the Absorption of Vitamin D in GIT: an Overview.” Journal of Food Science and Technology, vol. 54, no. 12, 2017, pp. 3753–3765., doi:10.1007/s13197-017-2840-0.

 

References for images

a Keane, Jeremy, et al. “Vitamin D and the Liver—Correlation or Cause?” Nutrients, vol. 10, no. 4, 2018, p. 496., doi:10.3390/nu10040496. (Figure 1)

b Liu, Wen-Chih, et al. “Vitamin D and Immune Function in Chronic Kidney Disease.” Clinica Chimica Acta, vol. 450, 2015, pp. 135–144., doi:10.1016/j.cca.2015.08.011. (Figure 2)

c “Vitamin D Deficiency Causes Osteomalacia and Rickets.” Kauvery Hospital, 9 May 2017, www.kauveryhospital.com/blog/k-way-health/vitamin-d-deficiency-causes-osteomalacia-and-rickets/. (Figure 3)

d “Alopecia Areata (Spot Baldness) Associated with 8.5 Ng Lower Levels of Vitamin D – Meta-Analysis April 2018.” Alopecia Areata (Spot Baldness) Associated with 8.5 Ng Lower Levels of Vitamin D – Meta-Analysis April 2018 |, 2018, vitamindwiki.com/Alopecia+areata+%28spot+baldness%29+associated+with+8.5+ng+lower+levels+of+vitamin+D+%E2%80%93+meta-analysis+April+2018. (Figure 4)

e “Vitamin D Deficiency and Chronic Muscle Pain | Moov India.” Vitamin D Deficiency and Chronic Muscle Pain | Moov India, www.moov.co.in/en/understanding-pain/understanding-the-relationship/. (Figure 5)

f Wimalawansa, Sunil J. “Associations of Vitamin D with Insulin Resistance, Obesity, Type 2 Diabetes, and Metabolic Syndrome.” The Journal of Steroid Biochemistry and Molecular Biology, vol. 175, 2018, pp. 177–189., doi:10.1016/j.jsbmb.2016.09.017. (Figure 6)

g Sanicas, Melvin. “Depression & Vitamin D Deficiency: Is There A Connection?” Medium, Medium, 27 May 2017, medium.com/@melvin.sanicas/depression-vitamin-d-deficiency-is-there-a-connection-1d2fefb45da2. (Figure 7)

h Mahmood Al-Janabi, Ammar Zaki. “Vitamin D and Prostate Cancer.” LinkedIn SlideShare, 11 Aug. 2016, www.slideshare.net/AmmarZakiMahmood/vitamin-d-and-prostate-cancer-64920491. (Figure 8)

i “Nature Made, D3, Ultra Strength, 5000 IU, 90 Softgels.” IHerb.com, sg.iherb.com/pr/Nature-Made-D3-Ultra-Strength-5000-IU-90-Softgels/76914?gclid=CjwKCAjwvuzkBRAhEiwA9E3FUv_Mug_oLR0C_uNeHIiGeXl5BkwU_g4CIP_5tR9yirzJeiED8Mdf3RoCPwMQAvD_BwE&gclsrc=aw.ds. (Figure 9)

j “Sperti Vitamin D Sunlamp.” SPERTI, 22 Mar. 2019, www.sperti.com/product/sperti-vitamin-d-light-box. (Figure 10)

k “Coeliac Disease.” Bupa.com.au, 2013, www.bupa.com.au/health-and-wellness/health-information/az-health-information/coeliac-disease. (Figure 11)

l “Effect of Crohn Disease Biologics.” Jama, vol. 317, no. 20, 2017, p. 2055., doi:10.1001/jama.2017.5897. (Figure 12)

m “Gastric Bypass Surgery, Roux-En-Y Gastric Bypass – Suwanee, Johns Creek, Alpharetta.” Atlanta Bariatrics, www.atlantabariatrics.com/weight-loss-surgery-options/gastric-bypass/. (Figure 13)

n “Nephrotic Syndrome.” UNC Kidney Center, 2018, unckidneycenter.org/kidneyhealthlibrary/glomerular-disease/nephrotic-syndrome/. (Figure 14)

o Kilbane, Sheila. “Fanconi Syndrome Is the Overall Dysfunction of the Proximal Renal Tubules, Resulting in the Loss of Amino Acids, Prote… | Pediatric Board Exam Studying | Pinterest | Failure to Thrive, Pediatrics and Disorders.” Pinterest, www.pinterest.com/pin/307370743296518657/?lp=true. (Figure 15)

p Alshahrani, Fahad, and Naji Aljohani. “Vitamin D: Deficiency, Sufficiency and Toxicity.” Nutrients, vol. 5, no. 9, 2013, pp. 3605–3616., doi:10.3390/nu5093605. (Figure 16)

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127 Comments
  1. Great insights into the topic of Vitamin D deficiency. The writer had stressed the symptoms and risk of this illness and had coupled with his own thoughts and ideas on how to prevent this deficiency. His thoughts are well-organised, making the entire article a comprehensive read as a result. The pictures used were able to illustrate his points effectively, thereby giving readers a better idea of this topic. Tips were included on how to ward off Vitamin D deficiency, and they were explained using science, making them more convincing as a result. In conclusion, this article was insightful and well-written.

    • I loved this article. There are so many useful tidbits that one would be hard pressed to find elsewhere. For instance, the article describes the distinction between Vitamin D2 and D3, their unit of measurement (IU) and most importantly how this unit relates to something tangible. When a patient is told to take a pill of 2000 IU Vitamin D3 everyday, he might not know how exactly this would affect his 25(OH)D level. However, using the rough guide given in this article, the patient can surmise that his level would rise by approximately 20ng/ml over a few weeks. He will also better understand that this increase will be gradual and not instantaneous, so the likelihood that he complies with his doctor’s advice and finishes his course fully will be much higher.

      Some people also mistakenly think that more is better and may consume more vitamin d pills than necessary overzealously. By detailing the symptoms of vitamin d toxicity such as kidney failure, the author has done a good job putting these harmful misconceptions to rest.

      By examining the causes of vitamin d deficiency like impaired digestive system and kidney/liver, the author has also ensured that patients afflicted with disorders like Coeliac disease or Nephrotic syndrome can check whether vitamin d deficiency accounts for any of the problems they may be facing.

      Overally, this is an excellent article that presents all there is to know about vitamin d deficiency in an easy-to-understand manner.

    • More informative.Good references.Great job.

      • What a detailed research made by Ashwin!! I never knew these much things r der to know about Vitamin D!! A full fledged deep study made by him !! Really proud of u Ashwin!!

        • This is a beautifully simplified presentation of the complex issue of vitamin d deficiency. I am an engineering student who has dropped biology years ago, yet I am still able to understand the effects of vitamin d on our body. This is in no small part due to the author’s use of illustrations. For instance, just by looking at the first figure, one can deduce that vitamin d can either be got through foods (in which case the small intestine is involved) or from sunlight (in which case the skin is involved), afterwhich it is modified in the liver first and finally the kidney. This active form is now ready to affect our bones, immune cells, liver cells and so on. The author’s figures not only illustrate the content heavy mechanisms, but also serve as a summary of points from time to time. One example would be the picture with all the food sources of vitamin d, so the reader does not have to scan the lengthy article for the different food items, but can look at the image for a quick and easy reference. Last but not least, the author also has figures that show the severity of vitamin d deficiency. The pictures showing the curved bones for rickets and bald spots on the head are scary and are far better at motivating the reader to avoid vitamin d deficiency than just words.

        • Muthukumar palanisamy August 24, 2019 at 8:26 am

          Good narration about vit d. Very informative

        • A good article on vitamin D in simplified form.

      • I always had a different perception about Vitamin D deficiency. This article gave an absolute in-depth view on the subject. A well researched write- up by this bright future Doctor. A very clear submission. Looking forward for more such article from Ashwin. Best wishes!

  2. Great insights into the topic of Vitamin D deficiency. The writer had managed to stress the significance of this illness effectively. Tips were provided on how to ward off this deficiency, and they were backed up through science, thereby making them more convincing. The pictures used were able to illustrate his main points, so readers could get a better grasp of the topic. In conclusion, this article was comprehensive and insightful.

    • Detailed description about vit D. Very informative article.

    • Well written article on vitamin D in simple and easy to understand.

    • Reply
      Vijaykumar Rajendran August 24, 2019 at 3:52 am

      Well written article on vitamin D in simple and easy to understand.

    • Well written article on vitamin D in simple and easy to understand.

    • Well written article on vitamin D in simplified form.

    • Very informative and well-written. Learnt a lot from this wonderful article. I especially like how ashwin organised the article; he explicitly highlights the main points and elaborates right after (also being sure to explain any possible jargon), which makes it clear and easy to follow. Good job!

    • Wonderfully detailed article about Vitamin D. I learned a great deal about the importance of it to optimal bodily functions, the perils of being deficient in it and measures to ensure that one has sufficient levels of the vitamin. The language used was also easy to understand, despite the, at times, dry and information-heavy content.

    • Great piece of writing! The author does an amazing job breaking down complicated concepts into simple and clear explanations. Easily digestible and an enjoyable read for readers with different background knowledge in this field.

    • Reply
      Palanisamy Krishnakumar August 11, 2019 at 8:24 am

      The writer has depicted the importance of vitamin D in humans, its effect on good health, symptoms of deficiency, measures to treat avoid improve the intake scientifically and naturally in different environment conditions where humans are habituated their food habits age related requirements etc in a simple and vivid language
      Very useful informative article
      Could be useful for further research and setback for current medical practicing to find the root cause for certain chronic diseases

      • Reply
        Muthukumar palanisamy erode August 24, 2019 at 8:26 am

        Good narration about vit d. Very informative

      • Well articulated, depth of the matter is there with vivid points, pictography and graphs to ensure simplicity. Usage of references are very much commendable. Continue to write other topics which could be an eye opener for many.

    • The writer has depicted the importance of vitamin D in humans, its effect on good health, symptoms of deficiency, measures to treat avoid improve the intake scientifically and naturally in different environment conditions where humans are habituated their food habits age related requirements etc in a simple and vivid language
      Very useful informative article
      Could be useful for further research and setback for current medical practicing to find the root cause for certain chronic diseases

      • A well analysed article giving elaborate details on importance of Vitamin D. Wasn’t aware that Vit D helps in absorption of calcium and phosphorus amd many other such facts. Kudos Ashwin and keep up the good work.

  3. I have vitamin D deficiency n also have same symptoms which are already ashwin you have given I thought vitamin D only sunlights problems but after read your article only I learned it leads to some more deficiencies and problem
    Am 37 yrs old but now itself I had knee bone problem n giddyness n indigestion pbm
    Now Only I got the reason for my problems
    Thanks ashwin thank you so much for your remedies for my problem also thanks to Fitness savvy for posting this article

  4. Well written article, simple yet comprehensively explains the facts to details. Good luck for the author

    • My blood tests a few years ago showed abysmally low vitD levels. I looked up so many articles online to see how to increase it naturally but nothing (including my doctor) was able to give me a clear idea of how vitD was synthesized, how much was needed and how the body used it. This article very clearly and comprehensively explains all the questions I had. The use of labelled diagrams, charts and tabulation helps a clear picturization of the entire process and let’s us choose a path that will suit our lifestyle best. Amazingly well written article..

      • I always had a different perception about Vitamin D deficiency. This article gave an absolute in-depth view on the subject. A well researched write- up by this bright future Doctor. A very clear submission. Looking forward for more such article from Ashwin. Best wishes!

  5. The article is very informative. It makes reader aware of the importance of Vit D. And the overdose of it.
    When I buy my calcium supplement I will look for one that has Vit D!

    • Well articulated, depth of the matter is there with vivid points, pictography and graphs to ensure simplicity. Usage of references are very much commendable. Continue to write other topics which could be an eye opener for many.

    • The writer has depicted the importance of vitamin D in humans, its effect on good health, symptoms of deficiency, measures to treat avoid improve the intake scientifically and naturally in different environment conditions where humans are habituated their food habits age related requirements etc in a simple and vivid language
      Very useful informative article
      Could be useful for further research and setback for current medical practicing to find the root cause for certain chronic diseases

    • Excellent paper on Vitamin D.Good and excellent way of presentation. Keep it up. Best wishes for a great successful future.
      May God bless you to achieve all your goals

  6. Very informative article on Vit D.
    A lot of effort must have been put in to do such a write out. Surprise to know that Deficiencies of vit D can cause so many effects on one’s health.

  7. Wonderful write up Ashwin????Very informative and in detail??

    • Excellent article and great insight about Vitamin D , here in US primary physicians started routinely monitoring the patients Vitamin D levels but not explaining in detail but Ashwin captured all those details and very helpful. Great job and Good luck.

  8. Great article, Ashwin! Lots of useful information in an easily accessible form.

    • It is well elaborated and descriptive. The references made can show that the writer has put in alot of research and effort.It is also not that complicated to understand the concepts considering the fact that even I could get the insight of the topic.Overall,the write-up was very interesting and informative!!!

  9. A very detailed and interesting explanation on vitamin D. Well incorporated and informative article detailing on deficiency of the vitamin , its sources,treatment and causes of deficiency. Great job.

    • It is very useful for the persons following Paleo Diet.Vitamin D deficiency is common among Paleo Diet followers.Already I am searching for the remedy and it will be useful for us.It is very clear description about vitamin D deficiency.Thank you

    • The article was easy to understand even for people like me, who do not have much information about this topic. The writer had explained his points with depth and a lot of effort was clearly put into writing this article. In conclusion, this was a very comprehensive article. Good job!

    • Article is very informative.Good work Ashwin ???

      • This was an extraordinary article with a very good flow on the topic of Vitamin D deficiency. The first section illustrates the often understated importance of Vitamin D by explaining what can happen when there is insufficient Vitamin D. This then leads on to the following section where the author explains a few ways through which Vitamin D deficiency can be treated. He then ends the article by going through a few risk factors for this condition, ensuring that the discerning reader is forewarned with the knowledge to take care of himself in the best possible way. Tables and graphs lend credibility to what is being presented. Overall, it is a very good article that highlights the prominent role Vitamin D plays in our bodies.

      • In a simple language he made us understand about vitamin D !

      • Detailed information in layman terms awesome !

      • Excellent information and Very informative article in layman terms !
        Keep it up 🙂

        • Great article! Thoroughly examins the topic of Vitamin D deficiency yet is extremely easy to follow even for someone like me with minimal knowledge in biology/chemistry. Author did a great job simplifying complex scientific terms and processes with the clear use of statistics and diagrams. Would highly recommend as reading material for high school and undergraduate students looking to learn more about this field. Author is also thorough in listing his references for those seeking advance readings.

      • Excellent information and Very informative article in layman terms !
        Keep it up 🙂 Ashwin

      • Very informative article in layman terms !
        Keep it up 🙂 Ashwin

        • Sujatha Palaniswamy August 21, 2019 at 6:05 am

          The author has done a masterful job tying in all the different sections. While reading the article I felt like I was directly having a conversation with the author. Whatever questions I had after reading one part of the article were quickly addressed in the next. After reading about the many symptoms of Vitamin D deficiency, I naturally wanted to find out how to avoid or treat this and this was addressed in the next section. The author had explained all the options in detail. After reading how Vitamin D can be obtained so easily by eating specific foods or even by just being under the sun for a very short period of time, I was wondering how will anyone get Vitamin D deficiency. This was again addressed later as I learnt about how impaired body functions and usage of certain drugs can decrease the absorption and metabolisation of vitamin D.Thus I feel that this article flows very well.

  10. Well researched article that is simultaneously comprehensive yet easy to read. Author clearly knows the subject matter well, going in depth into the physiological and biological aspects of vitamin D deficiency. His list of the symptoms, treatments, and causes was concise and helpful for people concerned about this affliction.

    All in all, this article is both a rigorous examination of vitamin D deficiency that will interest any medical professional, but is also digestible enough to serve as a helpful guide for normal people simply interested in the condition.

  11. Article is very informative.Good work Ashwin ???

    • Great wisdom about Vitamin D. Since I am vegetarian this article helped me about to know where we get Vitamin D in veg food. Especially eye opener is Exposure to Sunlight how vitamin D produced. Thanks Ashwin for the great article.

      • This article is pertinent, useful and engaging. The writer really knows how to simplify scientific jargon and make it understandable for dilettantes like me. Great job!

    • The article was very informative and succinct. The author explained the benefits of a necessity of vitamin D, problems with the lack of it, where to acquire vitamin D, and even what happens when there is too much vitamin D.
      The article in conjunction with the diagrams help the reader to gain insight into the benefits of Vitamin D.
      This was a very well researched article.

      • This article Very useful with pictorial presentation to understand.

      • Great wisdom about Vitamin D. Since I am vegetarian this article helped me about to know where we get Vitamin D in veg food. Especially I’m not aware of old age people problem with Vit D and it’s clearly mentioned here.

        • This is a commendable article on Vitamin D, well researched and gives all the necessary information!

  12. Amazing research and very informative article.

    • Learnt a lot about vitamin D and why is it good for humans and bones. Ashwin is such a talented writer and I learnt lots from him.

  13. Very informative article. Interesting to know the effects of vitamin D deficiency.

  14. The article is very informative and succinct. The author explains the necessity and benefits of Vitamin D, the problems when one doesn’t get enough, how to acquire it, and even what happens when one gets too much.
    The article was made even easier to understand through the inclusion of the diagrams. This was a very well researched article.

  15. Reply
    Balaji Veerappan M.D., FACC August 10, 2019 at 4:59 am

    A very thorough and well written review of a topic which many physicians may not have read about in a long time! Thank you

  16. Excellent piece of work. So well written and referenced. Ashwin wishing a bright career in Medicine in london

  17. Good read! I loved how you succinctly explained Vitamin D deficiency and its harmful effects. You seem extremely passionate and driven with regards to diagnosing and treating diseases – important traits for a successful doctor and clinician!

  18. Your article helped us realize that our problems are typical, and we can solve them in constructive ways.

    Well written and keep these good articles coming.

  19. Wow the article was written so well. It explained everything one needs to know about vitamin D.

  20. Congratulation Ashwin for the wonderful article on Vit D deficiency state_ the causes, manifestation,nutritional sources,treatment aspects.As you rightly pointed out, it is also important for immunological function. There are studies which shows it’s usefulness in the management of severe
    respiratory ailments.There is another practice of supplementing Vit D drops for all newborn babies up to the age of one year to take care of their increased demand. The nutritional deficiency will manifest only when the pt is growing. So in case of malnourished children, rickets won’t manifest clinically.
    The presence of alopecia in a pt with rickets signifies the possibility of VitD dependent rickets.You have given the beautiful self explanatory pictures. The way you have approached the topic is excellent.
    Keep going.
    Wish you best of luck.

  21. Congratulation Ashwin for your excellent article on Vit D deficiency – the causes, manifestation, nutritional sources ,& treatment aspects. As you have rightly pointed out, it is also important for immunological function. There are studies which support the use of VitD in the management of severe respiratory diseases.
    There is another practice of supplementing VitD to all newborn upto the age age of one year to take care of their increased demand. You have described the complication of excessive intake of VitD beautifully. The alopecia totals is a useful clue for Vit D depended rickets ( a type of hereditary rickets).
    The pictures are self explanatory .
    Well done.
    Keep going
    Wish you good luck.

  22. Congratulations Ashwin. Well done and explained in depth about vitamin D deficiency. I think now in present world many people suffer from this deficiency. Your article really good. Keep going and reach to grow great heights. My best wishes.

  23. Thanks. An eye opener. I’m currently having very low vitamin D levels and undergoing treatment. Surely can relate to most of the symptoms.

  24. Was looking for treatments for vitamin D deficiency. This article provided that and much more. Very well-researched piece. Writer deftly balances his discourse on vitamin D deficiency to include both a comprehensive, analytical examination of the scientific mechanisms of the deficiency, but also a succinct and helpful list of the symptoms, causes, and measures that are meant for laymen like me. Writer conveyed his points clearly and effectively. Thanks to the author and thanks to FitnessSavvy for publishing this article.

  25. Enjoyable read! This article was easy to follow. I only knew vitamin D was important for strong bones but after reading this article, I can now understand just how essential they are. The myriad of issues that can arise when one does not have enough Vitamin D was really surprising to me and has left me with a much greater respect for Vitamin D.

    I was also surprised by the fact that there are so few natural food sources of Vitamin D, especially for vegetarians. I thought such an important vitamin would have been present in nature in much greater abundance.

    This informative article was written in a way that was easy to understand and the accompanying pictures nicely illustrated the points being presented. All this ensured that I could understand the entire article from start to end.

  26. Thanks for citing all your sources! Too many articles like this on the internet are hard to trust, but not this one. It is evident that research was done in its writing.

  27. Since the discovery of vitamins in the early 1900s, the vitamin industry has grown to be multi-billion dollar industry. I was glad to be able to read about the myths and truths of vitamins neatly organised in a well written article. From a Science and Business background, I always found viral marketing around vitamins to have gone too far and would definitely recommend anyone interested in the facts to read this article. Not only does Ashwin reference scientifically-rigorous research but also breaks it down in a way that is easier to understand, with accompanying illustrations.

    It was also interesting to note that someone could actually overdose on Vitamin D (Ashwin writes about Vitamin D toxicity in addition to its deficiency) and thus the supplements should not be taken lightly, rather treated as a any other medicine. I have seen a fair share of companies marketing their supplements as completely harmless/only beneficial and encouraging a “better safe than sorry” mentality just to sell more of their product. Understanding that you should indeed visit a doctor with regards to your vitamin levels should indeed be taught to more people.

    Props to Ashwin for tackling the behemoth of information surrounding vitamins and getting to the bottom of Vitamin D.

  28. This article made me smarter. Well-structured and informative. Clearly a lot of work and time has been dedicated on the good research.

  29. Today’s most common problems like fatigue, hair fall and depression have been explained. Almost everyone today has low levels of vitamin D. This article so efficiently explains why and how to correct the problem. Kudos to the author. Such a well researched and well written article.

  30. Very interesting article regarding vitamin D deficiency.
    It is important to understand how we can be affected by vitamin D deficiency based on factors like sunscreen usage or hometown (near of far from the equator).

  31. Excellent article, provides insights on Vitamin D significance to our health. Pictorial illustrations are well structured and clear for readers to understand the benefits/ effects. Highly recommend this one for Vitamin D reference.

    • Was browsing through different articles and came across this one and I had to write a comment even though I rarely do so. This article was highly informative and well put together. It answered all the questions I had about the effects and benefits of vitamin d or lack thereof. I have and will continue to share this article to relatives and friends to inform them about the importance of vitamin.

    • Article was very informative and well-written! The illustrations and charts made it very easy for readers to understand and follow. 🙂

  32. Excellent article, provides insights on Vitamin D significance to our health. Pictorial illustrations are well structured and clear for readers to understand the benefits/ effects. Highly recommend this one for Vitamin D reference.

  33. Nicely written! I really love how the article is well accompanied by apt illustrations, and how the use of superscript numerals for citation gave the article a very clean appearance for reading.

    As someone without a strong scientific background, I was able to learn more about the importance of Vitamin D without being overwhelmed by facts and processes. As such, it has definitely inspired me to be more interested in Vitamin D, and the ways I can employ to improve my overall well-being. Good job!

    • Great article with detailed explanation. Here in US the physicians started monitoring the Vitamin D level for the past few years but they don’t explain much to their patients. Ashwin did a great job proving the insight and it will be a great help. Kudos to him and Good luck.

  34. Very well constructed article explaining the causes and symptoms of Vitamin D deficiency and what we can do to prevent it from happening. I thought there was very good use of diagrams as well as they facilitated the better understanding of the content and concepts being mentioned in the article. Overall and very clear and helpful write up especially considering Vitamin D deficiency might happen to anyone who is not too careful about it. Well done to the author!

    • Great well researched article on vitamin D! It’ll be very useful to plan my diet for a healthier way of living . Hope to see more papers published from this author.

  35. This article is pertinent, useful and engaging. The writer really knows how to simplify scientific jargon and make it understandable for dilettantes like me. Great job!

    • Was browsing through different articles and came across this one and I had to write a comment even though I rarely do so. This article was highly informative and well put together. It answered all the questions I had about the effects and benefits of vitamin d or lack thereof. I have and will continue to share this article to relatives and friends to inform them about the importance of vitamin.

  36. A very interesting, well researched and informative article on Vit D deficiency. Thoroughly enjoyed it. Keep up the good work, Ashwin!

  37. An impressive article explaining Vitamin D deficiency in a clear and understandable manner. The author has surely done extensive research on this matter and yet could simplify all the scientific jargon for the public to understand. The structuring of this article also makes it easy to follow, going straight to the point and yet informing us of all the necessary details. Personally, I do take many supplements and was considering taking Vitamin D supplements. Though I have learned the importance of Vitamin D in aiding our immune system and our general health, I have also learned that through my diet and exposure to sunlight may actually be sufficient. Throughout this article, I could feel the enthusiasm coming from the author. Ashwin has surely been passionate about this topic and has a heart in informing the public about common yet underrated health issues. Keep up the good work and I can foresee a great future for you!

  38. A great read which was easy to follow. Every point was written concisely with clear language, which made the entire article a joy to read and understand. The main points were summarised well before every detail was explained clearly, and the diagrams / images added made the article even better of a read.

  39. Reply
    Balaji Veerappan MD, FACC August 18, 2019 at 10:11 pm

    Fantastic and thorough review! Very well written with a lot of detail! Thanks!

  40. This article really helped me understand the implications and effects of Vitamin D deficiency better. And it also provided helpful measures to take in the case of Vitamin D deficiency. This article really made this condition alarming to me and I would definitely recommend this as a good read.

  41. Covers all the bases.. good one

  42. This article was wonderful. I love how you have organised it so well. Firstly, you talked about the symptoms, then the treatments and finally the causes. I feel that I have heard a lot about vitamin D over the years, however, this seems to be one of the few articles I have come across that really discusses the issue very well. You have made wonderful use of images and honestly this was such an enjoyable read. Can’t wait to see more of your articles!

  43. Very informative passage, with clear diagrams interlaced with the content. For an incredibly complex issue, the author has presented his key points well with good balance of detailed technical knowledge and summaries. As someone about to live abroad in Europe for several years away from my equatorial home, vitamin D deficiency is definitely a condition I should pay more attention to in terms of my nutrition/lifestyle. This article definitely helps in giving me a better understanding of vitamin D’s role in the human body as well as related medical topics.

  44. Very informative passage, with clear diagrams interlaced with the content. For an incredibly complex issue, the author has presented his key points well with good balance of detailed technical knowledge and summaries. As someone about to live abroad in Europe for several years away from my equatorial home, vitamin D deficiency is definitely a condition I should pay more attention to in terms of my nutrition/lifestyle. This article really helps in giving me a better understanding of vitamin D’s role in the human body as well as related medical topics.

  45. Great work! This is The Vitamin D 101 guide that we have all been waiting for. The article comprehensively summarizes many of the current medical opinions and research on the various aspects of Vitamin D deficiencies, such as its symptoms, treatment and pathophysiology. In doing so, the author aims to highlight the importance of Vitamin D in our lives and inform us on how to maintain healthy levels of Vitamin D to combat its possible deficiency.

    While the article is largely written in an easy-to-understand and approachable tone, Ashwin’s appropriate citations of established journals to substantiate his points makes it highly scientific and credible. For example, he cites data and statistics from research papers [19,20] from The Journal of Endocrinology and Metabolism in discussing the biochemical efficacy of Vitamin D2 and D3 as Vitamin D precursors. In the article, Graph 1 also clearly visualizes the difference in subsequent serum level activity while Table 1 also provides an overview comparison of biological activity in Vitamin D2 and D3 intakes. This distinguishes the article from many others that tend to oversimplify the logical flow from the intake of Vitamin D sources to its actual biological activity and lends a great deal of trustworthiness to the subsequent recommendation of daily dietary allowance of Vitamin D.

    On the other hand, the author also makes the effort to avoid a mindless regurgitation of technical information, by tying in specific and practical medical advice he logically concludes from his scientific references, while presenting it in a relatable daily context to emphasize its importance. For example, in his discussion of the treatment options available for Vitamin D deficiency, he mentions that while fish and seafood are excellent natural food sources of Vitamin D, eggs and mushroom are a good alternative for people who may practice some sort of veganism. He also acknowledges that the recommended dosages for Vitamin D supplements should be carefully considered with the patient’s BMI and thus opines that the natural synthesis of Vitamin D by the human body in sunlight is a safer alternative to avoid any form of toxicity. This provides a well-balanced perspective to article and also encourages the audience to understand the medical information presented and interpret it suitably into their various lifestyles.

    All in all, Ashwin Venkatakrishnan concludes that Vitamin D is a natural hormone that is crucial to the healthy functioning of our bodies, and while there may be several risk factors that predisposes one to its deficiency, we are fortunate that there are simple and effective means to treat it. He has done an amazing job in terms of writing a highly scientific and balanced article by drawing well-informed conclusions from reliable sources to put forth his point.

    Keep up the good work and wish you all the best in Med school!

  46. Very informative and well written. The material is covered very thoroughly and the images and diagrams made understanding the topic a lot easier. Kudos to the writer

  47. A very well-written article with relevant references which simplifies the topic for readers to understand it easier. The content is very informative and the use of diagrams are appropriate in aiding the visualisation of the elaborated content.

    • Very informative article with detailed explanation of Vit D and its relevance to human body. Simple language yet covers all the aspects. Diagrams makes it all the more easier to comprehend. I have Vit D deficiency and have done some reading around. However, Ashwin’s article sums up everything and is an eye opener of sorts. Thanks, and I leave with more insight and determination to follow some of the recommendations!

  48. A very well-organised and detailed article! The use of diagrams and graphs made the article a much easier read. The use of scientific jargon also shows the author’s deep understanding of this topic, while the use of simpler english also allows easier understanding of the article for people of all education levels. The details presented also shows the thorough research done by the author.

    Personally, I learnt a lot about the symptoms of Vitamin D deficiency, which will definitely help me with early detection of this problem if it ever occurs to me.

  49. This is a wonderful article that explains everything one needs to know about Vitamin D. There are so many things that I have learnt from this article. I was surprised when I realised that there are actually two types of Vitamin D (D2 and D3), and they both have different biological effects, with D3 clearly being more effective than D2, as shown by Graph 1. Given that D2 is the vitamin more readily available to vegetarians and vegans as it is the one found in plant sources, I can understand how it is all the more important that they get adequate exposure to sunlight for alternative means of obtaining vitamin D. I also learnt for the first time that just because you ingest a certain amount of vitamin D does not mean that you absorb all of it and the fat content of the food you are eating actually makes a difference to how much is absorbed. Overall, this was a long and informative article that was made easier to read and understand because of engaging visuals.

  50. This is a wonderful article that I really enjoyed as it explains everything one needs to know about Vitamin D. There are so many things that I have learnt from this article. I was surprised when I realised that there are actually two types of Vitamin D (D2 and D3), and they both have different biological effects, with D3 clearly being more effective than D2, as shown by Graph 1. Given that D2 is the vitamin more readily available to vegetarians and vegans as it is the one found in plant sources, I can understand how it is all the more important that they get adequate exposure to sunlight for alternative means of obtaining vitamin D. I also learnt for the first time that just because you ingest a certain amount of vitamin D does not mean that you absorb all of it and the fat content of the food you are eating actually makes a difference to how much is absorbed. Overall, this was a long and informative article that was made easier to read and understand because of engaging visuals.

  51. Fantastic article on the importance of vitamin D to humans. I’ve learnt a lot from reading it. Ashwin has done a really good job with the scientific rigour and the large amount of references provided, while keeping the article understandable to a layperson. The article is also organised in a really easy to read fashion with clear sections and pointers. This is the best article online on vitamin D and issues relating to vitamin D deficiency. Good job Ashwin and all the best in medical school!

  52. Very informative and thorough. I first like the way this article was organized. Symptoms and treatments section, rather more practical, were placed before the causes section, helping the readers find what they want or what are they more interested in. This article was typically attractive on the way it develops from information on basic medicine to clinical medicine. Starting with covering biochemistry, immunology, and anatomy to applying into clinical situations makes it helpful for both non-med students and med students. Great work!

    • This article is systematically organised as it goes through the symptoms, treatment and causes of Vitamin D deficiency in order, allowing the reader to better understand the relations of the three aspects. Furthermore, the author also explains the key concepts of Vitamin D deficiency very thoroughly with the use of scientific terms, but at the same time making it easy to understand for the average reader with little chemistry and biology background. Overall, this is a very well-written and informative article that enriches our understanding of Vitamin D deficiency, its relevance to our daily lives and what we can do about it. Great job!

  53. With the amount of information accessible on nutrition and the role played by vitamins in our health, Mr. Venkatakrishnan’s article stands out as an incisive and thorough survey on Vitamin D deficiency. The selling point of this article is how it manages to present scientifically supported information, while staying very much true to its mission of communicating the symptoms, treatment, and causes of Vitamin D deficiency in an accessible manner. This article has something to offer to readers at all levels—for the uninitiated, there is sufficiently engaging content, backed up by well-curated visuals, to keep their attention; for the expert, the presentation of the content follows a logically sound sequence, and does not skimp on technical details. The meticulous management of sources, in the context of the text, ensures that this text can serve as a launchpad for further reading should the reader like to do so.

    Mr. Venkatakrishnan is clearly enthusiastic and knowledgeable in the field he has chosen to write about. Moreover, his attention to detail as well as to organization ensures that this article is, if nothing else, a pure joy to read.

  54. Well researched article …

  55. Well articulated, depth of the matter is there with vivid points, pictography and graphs to ensure simplicity. Usage of references are very much commendable. Continue to write other topics which could be an eye opener for many.

  56. Very well written and informative article. Learnt so many things and understood the importance of vitamin D. We have skipped several days on Vitamin D supplement for our daughter and now I see how big of a mistake it is.

  57. Before the article I knew that older people were more likely to have Vitamin D deficiency and if any one had a deficiency the #1 answer was to be in the sun more. However, there is a lot more information to be known about it and the article has educated me. It is well written and in simple terms so that anyone can understand it. Since I am a visual learner, the pictures and diagrams also helped. Of the new knowledge I have, 2 main takeaways I have will be to share the information related to how gastric bypass surgery can impair your body’s natural processing (as I have family and friends that have had this surgery) and how vitamin d deficiency can be related to depression.

  58. A well analysed article giving elaborate details on importance of Vitamin D. Wasn’t aware that Vit D helps in absorption of calcium and phosphorus and many other such facts. Kudos Ashwin and keep up the good work.

  59. This article is very systematically organised as it describes the symptoms, treatments and causes of Vitamin D deficiency in order, allowing the reader to better follow and understand the relations of the three aspects. The author has also explained the key concepts of Vitamin D deficiency very well, incorporating scientific terms but also making it easy to understand for the average reader with little chemistry or biology background. Overall, I feel that this is a very informative article that enriched our understanding of Vitamin D deficiency, its relevance to our daily lives and what we can do about it. Great job Ashwin!

  60. This article is systematically organised as it goes through the symptoms, treatment and causes of Vitamin D deficiency in order, allowing the reader to better understand the relations of the three aspects. Furthermore, the author also explains the key concepts of Vitamin D deficiency very thoroughly with the use of scientific terms, but at the same time making it easy to understand for the average reader with little chemistry and biology background. Overall, this is a very well-written and informative article that enriches our understanding of Vitamin D deficiency, its relevance to our daily lives and what we can do about it. Great job!

  61. Awesome article written @Ashwin. I feel that it is very easy to follow as it covers both breadth and width to give a comprehensive introduction into Vitamin D, through apt simplifications of the matter. Also, being a visual learner, the diagrams are very helpful when the biological processes mentioned gets too complicated as it allows readers to easily visualise the concepts. Great Job on that!

    In addition, being an engineer, units conversion is important to me as it is confusing and meaningless if values are provided but not the units. Hence, it is commendable that the author place emphasis to explain this conversion simply, so that further research could be done on it. Besides, I was genuinely surprised that a short 13 mins exposure in the sun is able to provide you with the vitamin D one needs, or that UVB rays cannot penetrate though glass as I have always been trying to sit near windows to increase my time spent “outdoors”. Thank you for clearing my misconception! I like how you include bits and pieces of fun facts around to make the article more engaging.

    With the amount of citations done, I am truly impressed at the amount of hard work and effort placed into writing this essay. Thank you for such an enlightening article. It really made me aware of the importance of vitamin D in our body.

  62. The article is well written and in formative. Recently I started hearing about Vitamin D deficiency. This article gives a lot insider understanding of the Vitman D. Very good work by Ashwin… best wishes for him.

  63. An informative and well-articulated piece which is easily digestible by a layman such as myself. I’ve always heard that the Sun provides us with vitamin D but now I understand why that is the case. This article attempts to maintain technical accuracy while making the concepts more readable and succeeds at both admirably. Reading this article has greatly increased my understanding of the importance of vitamin D, the various causes of vitamin D deficiency and their remedies. Good job Ashwin!

  64. An informative and well-articulated piece which is easily digestible by a layman such as myself. I’ve always heard that the Sun provides us with vitamin D but now I understand why that is the case. This article attempts to maintain technical accuracy while making the concepts more readable and succeeds at both admirably. Reading this article has greatly increased my understanding of the importance of vitamin D, the various causes of vitamin D deficiency and their remedies. Good job Ashwin!

  65. Reply
    Senthilkumar Ramaswamy August 26, 2019 at 6:34 am

    Ashwin this article is very nicely written its very informative and interesting.

    Below I have listed few information that was useful and new facts for me

    1. You simplified figure (fig 1) shows how vitamin D goes into the body, easy to understand.
    2. D2 & D3 details was a new information for me, I’m now searching for D2 vitamin rich vegetables & plants for eating.
    3. I did not know that free range eggs had 4 time more nutrition that the caged one.
    4. I learnt from you that mushroom has Vitamin D, I like mushrooms a lot
    5. Learnt about UVA, UVB, & UVC, did not know that early morning sun had UVB and why (UVB rays have low penetrating power) you should be in direct sun to get it into your body.

    I just highlighted only few points from your research but you have more information. It gave me enough information to enhance my Vitamin D intake. I also found your references more helpful and I could see you had done a thorough study of Vitamin D.

    Keep up your good work and do this a lot & don’t forget to send me your next research.

  66. An excellent in-depth analysis on vitamin D highlighting it’s nature, availability and importance for the human body. A great read for the health conscious public, medical students as well as the medical specialist for examining and presenting the science behind vitamin D and problems caused by its deficiency. The author has scientifically presented the issue whilst at the same time explaining it in simple terms and avoiding medical jargon. There is clear explanation of the science behind vitamin D synthesis and problems caused by its deficiency and details of corrective measures needed with excellent illustrations and logical presentation of facts. As a medical specialist myself, I had a great opportunity to refresh my knowledge on vitamin D. I was pleasantly surprised that this high quality article was written by a medical student. It is clear that Ashwin has set high standards for himself and I wish him the very best for his future medical career.

  67. Great insights into the topic of vitamin D. The paper is written in a very rigorous way, all facts and evidence are well supported with qualitative and quantitative research. This is also a very interesting academic paper to read. The information about deficiency and benefits of Vitamin D is laid out in a very logical format and is supplemented by interesting graphs and pictures. Thus, the article is very straightforward and is very entertaining to read. No wonder my mom always asked me to eat cog liver oil to help me grow more hair. Now I understand the reason behind.

    Thank you for composing such a great paper! Great job Ashwin!

  68. Great insights into the topic of vitamin D. The paper is written in a very rigorous way, all facts and evidence are well supported with qualitative and quantitative research. This is also a very interesting academic paper to read. The information about deficiency and benefits of Vitamin D is laid out in a very logical format and is supplemented by interesting graphs and pictures. Thus, the article is very straightforward and is very entertaining to read. No wonder my mom always asked me to eat cog liver oil to help me grow more hair hahaha. Now I understand the reason behind.

    Thank you for composing such a great paper!

  69. This article is an outcome of fantastic research on Vitamin D. The author has well-articulated with great coherence. He has presented the content precisely which helps the readers to understand the facts without much prior knowledge. The article is well narrated citing the references clearly. The list of figures used were very appropriate especially the figure 1, which depicts the methods of Vitamin D intake. The side effects of Vitamin D deficiency are elucidated with scary figures. Vitamin D2 and D3 are compared and Table 1 clearly shows that Vitamin D3 has more biological activity.
    The author has succinctly described the causes of Vitamin D deficiency. Normally we think that the supplements would help us increase Vitamin D level without knowing the risk of vitamin D toxicity. The author has even pointed out the symptoms of vitamin D toxicity and suggested thirteen minutes of sunlight exposure in midday to maintain healthy level. It is surprising to note that obese people have to take in more Vitamin D to raise their serum level.
    This article would definitely be a great resource for researchers.
    Personally I understood that Vitamin D deficiency is not to be taken lightly.

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