A few decades ago, people lived and worked outdoors. Children enjoyed playing in parks, clothes were hung outside to dry and people would cycle to nearby places. Almost everybody spent a good amount of time out in the sun.

But today’s world has a different story to tell. Children play on game consoles, clothes are dried indoors, a cab is easily available for even a short distance and the addiction to TV and the internet has limited our outdoor activities. What does this mean? To put it simply, you’re missing out on all the sunshine.

Vitamin D, also known as the ‘sunshine vitamin’, is produced when the ultraviolet rays of the sun strike the skin and trigger the synthesis of vitamin D.

Did you know that vitamin D is actually a pro-hormone and not really a vitamin? This is because vitamins cannot be synthesized by the body and need to be acquired through diet and supplements, whereas the body can make sufficient amounts of vitamin D from sun exposure.

The health benefits of vitamin D are numerous and it’s virtually impossible to list all of them here. However, here are the six most essential ones.

1) Boosts Immunity
Flu, cold and cough are the most common ailments that trouble everyone, from children to adults to the elderly. Illnesses occur when the main line of defense, the immune system, fails to function properly. Vitamin D stimulates the production of specific peptides in white blood cells and in epithelial cells (cells that form the surface of the respiratory tract) that fight infection and protect the lungs.[1]

A study published in the American Journal of Clinical Nutrition showed that school children that received 1200 IU of vitamin D per day had a 42 percent reduction in influenza A during the winter months as compared to children who took a placebo.[2]

2) Improves Brain Health
Over 5 million Americans have Alzheimer’s and it’s predicted that this number could reach 15 million by 2050.[3] Research says that around 90 percent of Alzheimer’s patients have low vitamin D levels.

A clinical study evaluated the effects of vitamin D on Alzheimer’s occurrence in elderly women. It was found that the group of women with the highest intake of vitamin D (20 percent of the total participants) had lower Alzheimer’s disease incidence.[4] Another study done in 300 elderly people found a 250 percent increase in the occurrence of Alzheimer’s in people with low vitamin D levels.[5]

3) Builds Strong Bones
Vitamin D promotes calcium absorption in the gut and maintains optimal calcium and phosphate levels to enable the normal mineralization of bones.

Vitamin D is needed for bone growth and bone re-modeling, a lifelong process in which mature bone tissue is removed by osteoclasts (cells that resorb bone tissue) and replaced with new bone tissue by osteoblasts (cells responsible for the formation of bone tissue).[6,7]

4) Manages Autoimmune Disorders
Autoimmune diseases are ones in which the body and its immune system (such as white blood cells, natural killer T cells, etc) get stimulated or tricked into attacking the body’s healthy tissues, something that doesn’t happen under normal circumstances.

Vitamin D is an immune system modulator. A study showed that adult women taking 400 IU of vitamin D every day had a 40 percent decreased risk of developing rheumatoid arthritis, which is an autoimmune condition.[8]

Another study showed that a high dose of vitamin D supplementation improved the symptoms of rheumatoid arthritis in 89 percent patients and 45 percent of them showed complete remission. This indicates that adequate vitamin D can benefit joints.[9]

5) Reduces The Risk Of Diabetes
Vitamin D promotes calcium absorption and utilization, preventing and curing rickets & osteomalacia (softening of the bones). Calcium is necessary for insulin secretion, which suggests that vitamin D may in a way helps in maintaining insulin secretion.[10]

6) Decreases Risk Of Multiple Sclerosis
The immunomodulatory effects of vitamin D can decrease the risk of multiple sclerosis. Studies show that an increase in vitamin D levels has an inverse relationship with the risk of multiple sclerosis.[11,12,13]

Types Of Vitamin D
Vitamin D2 and vitamin D3 are the two types of vitamin D. While D3 is synthesized in the skin after exposure to sun rays and from food sources such as cod liver oil, vitamin D2 is produced in the lab by exposing a plant sterol (compounds found in plants) to ultraviolet rays. Vitamin D3 is far more effective in preventing diseases than vitamin D2.

Is There A Difference In Vitamin D Obtained From The Sun & Vitamin D Obtained From Foods?
There is no essential difference in  the vitamin D obtained from the sun and that obtained from foods. Vitamin D is produced in the skin from a universally present form of cholesterol, 7-dehydrocholesterol. The ultraviolet B rays (UVB) convert this compound to vitamin D3.

Vitamin D is found in very few foods naturally. Fatty fish is the main source of vitamin D. Mushrooms and egg yolk are other good sources. Milk doesn’t naturally contain the vitamin, but is fortified with it.

For more interesting stories, visit our Health page. Read more about Diseases & Conditions here.

Read More:
Vitamin D Check: 5 Signs That Could Mean A Deficiency
4 Reasons To Optimize Your Vitamin D Levels (& How You Can Do It)
Vitamin D Foods: When The Sun Isn’t Enough
Hair Loss? Here’s A Much-Needed Dose Of Vitamin D To Strengthen Your Locks

1. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 May;91(5):1255-60. doi: 10.3945/ajcn.2009.29094. Epub 2010 Mar 10. PubMed PMID: 20219962.

2. Ginde AA, Mansbach JM, Camargo CA Jr. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009 Feb 23;169(4):384-90. doi: 10.1001/archinternmed.2008.560. PubMed PMID: 19237723; PubMed Central PMCID: PMC3447082.

3. Alzheimer’s Association. Alzheimer’s Facts and Figures. Fact Sheet. site: http://www.alz.org/facts/overview.asp. Accessed on 18 Aug 2015.

4. Annweiler C, Rolland Y, Schott AM, Blain H, Vellas B, Herrmann FR, Beauchet O. Higher vitamin D dietary intake is associated with lower risk of alzheimer’s disease: a 7-year follow-up. J Gerontol A Biol Sci Med Sci. 2012 Nov;67(11):1205-11. doi: 10.1093/gerona/gls107. Epub 2012 Apr 13. PubMed PMID: 22503994.

5. Annweiler C, Llewellyn DJ, Beauchet O. Low serum vitamin D concentrations in Alzheimer’s disease: a systematic review and meta-analysis. J Alzheimers Dis. 2013;33(3):659-74. doi: 10.3233/JAD-2012-121432. Review. PubMed PMID: 23042216.

6. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.

7. Cranney A, Horsley T, O’Donnell S, Weiler H, Puil L, Ooi D, Atkinson S, Ward L, Moher D, Hanley D, Fang M, Yazdi F, Garritty C, Sampson M, Barrowman N, Tsertsvadze A, Mamaladze V. Effectiveness and safety of vitamin D in relation to bone health. Evid Rep Technol Assess (Full Rep). 2007 Aug;(158):1-235. Review. PubMed PMID: 18088161.

8. Racovan M, Walitt B, Collins CE, Pettinger M, Parks CG, Shikany JM, Wactawski-Wende J, Manson JE, Moreland L, Wright N, Jackson R, Howard BV. Calcium and vitamin D supplementation and incident rheumatoid arthritis: the Women’s Health Initiative Calcium plus Vitamin D trial. Rheumatol Int. 2012 Dec;32(12):3823-30. doi: 10.1007/s00296-011-2268-1. Epub 2011 Dec 22. PubMed PMID: 22190273.

9. Schwalfenberg GK. Solar radiation and vitamin D: mitigating environmental factors in autoimmune disease. J Environ Public Health. 2012;2012:619381. doi: 10.1155/2012/619381. Epub 2012 Jan 11. Review. PubMed PMID: 22523507; PubMed Central PMCID: PMC3317188.

10. Boucher BJ. Vitamin D insufficiency and diabetes risks. Curr Drug Targets. 2011 Jan;12(1):61-87. Review. PubMed PMID: 20795936.

11. Ascherio A, Munger KL, Simon KC. Vitamin D and multiple sclerosis. Lancet Neurol. 2010 Jun;9(6):599-612. doi: 10.1016/S1474-4422(10)70086-7. Review. PubMed PMID: 20494325.

12. Munger KL, Zhang SM, O’Reilly E, Hernán MA, Olek MJ, Willett WC, Ascherio A. Vitamin D intake and incidence of multiple sclerosis. Neurology. 2004 Jan 13;62(1):60-5. PubMed PMID: 14718698.

13. Weinstock-Guttman B, Mehta BK, Ramanathan M, Karmon Y, Henson LJ, Halper J, Riskind P. Vitamin D and multiple sclerosis. Neurologist. 2012 Jul;18(4):179-83. doi: 10.1097/NRL.0b013e31825bbf35. Review. PubMed PMID: 22735240.