Vitamin D and Your Health
Vitamin D is a hormone essential to cellular development and immune health; virtually every cell in our bodies makes use of it. Vitamin D is created primarily in our skin during sun exposure, and we can also get it in our diet and with nutritional supplementation. However, because so many of us live at northern latitudes where the sun is low in the winter, work indoors, and don't take adequate nutritional supplementation, most of us are deficient in this vital nutrient.
This is especially true for people of color because those with darker skin need five to ten times longer in the sun to create the same amount of vitamin D as lighter skinned people. I'll write more below about the disturbing racial disparities in Vitamin D deficiency, a public health crisis receiving little attention from our government.
In brief, Vitamin D plays a vital role in the prevention and treatment of
•Cancer
•Heart Disease
•Osteoporosis
•Diabetes
•Multiple Sclerosis
•Learning disabilities
•Depression
•Colds and Flu
•Autoimmune diseases, and more
The Health Protecting Effects of Vitamin D:
Cancer Prevention
•The processes of cell growth and division become imbalanced without adequate Vitamin D. In a summary of existing research, the New England Journal of Medicine reported 30-50% more cancers in Vitamin D deficient people. And the Journal of Clinical Nutrition reported a new, carefully monitored study showing an amazing 60-77% reduction in the development of cancer among post-menopausal women taking Vitamin D. Maintaining adequate levels of Vitamin D in the blood is one of the best steps you can take to prevent cancer.
Heart Disease
•Multiple studies have demonstrated that adequate levels of Vitamin D in the blood lower cholesterol, blood pressure, and the formation of arterial plaques. Also, researchers have found that the further from the equator one lives, the greater the risk of heart attack. This is explained when we remember that the sun is lower farther from the equator, and that natural Vitamin D production in the skin thus lower. Heart attacks surge in the winter, but only in the northern latitudes where the sun is the lowest. Even more, Vitamin D supplementation has been shown to be at least as effective as statin drugs in reducing heart attacks, but without the side effects. To prevent heart disease over your lifetime, eat a healthy diet, exercise, and maintain adequate levels of Vitamin D.
Colds, Flues, and Other Infections
•Vitamin D promotes the health and development of red blood cells and strengthens other immune system cells including natural killer cells, neutrophils, and monocytes. Studies have shown that children with adequate Vitamin D in their blood get fewer respiratory infections, and demonstrated how Vitamin D supports the ability of the body to fight off powerful invaders such as tuberculosis. If you have a skin infection, Vitamin D will help it to heal more quickly; if you want to prevent the transmission of colds and flues, take Vitamin D.
Osteoporosis
•Vitamin D regulates calcium absorption in the bones. Most people get enough calcium in their diet, but not enough Vitamin D to enable that calcium to be well used. A recent study showed that bone loss increased as Vitamin D levels dropped below 45 ng/mL. To support long-term bone health, exercise, eat a balanced diet, and supplement with Vitamin D as needed.
Pregnancy and Preventing Learning Disabilities
•Brain development takes place most quickly during the first half of pregnancy, and depends on adequate levels of Vitamin D. This explains the disparities in learning disabilities in children according to birth month; in Boston, where the sun is low in the winter and Vitamin D levels thus low in pregnant mothers, boys born in July and August were found to be seven times as likely to develop learning disabilities as boys born in the winter. Other studies have shown increased levels of grade level retention and lower standardized test scores in summer-born children. Related research on pregnant rats has shown Vitamin D deficiency to lead to brain abnormalities in offspring. To promote optimal brain development, pregnant women should maintain adequate levels of Vitamin D throughout pregnancy.
Diabetes
•The Journal of the American Medical Association noted significant reductions in both Type II diabetes in adults and Type I diabetes in children among those receiving adequate levels of Vitamin D.
Why we Don't get Enough Vitamin D
The human species evolved near the equator, wearing few clothes, and enjoying abundant sun. As the species began to disperse, those wandering further from the equator developed lighter skin to allow the sun's rays to penetrate and produce the needed Vitamin D. With industrialization and urbanization, most of us work indoors in cities, and cover up extensively with clothing and sunscreen during our rare moments in the sun. All of this blocks the formation of Vitamin D.
In the United States today, Vitamin D deficiency ranges from 36% among healthy young adults, to 57% in the general adult population, to 100% among the elderly. (As we age we become gradually less efficient at producing Vitamin D.) Even in sun-drenched Miami, a 40% deficiency was found in winter .
A Public Health Crisis Among People of Color
Vitamin D deficiency is especially prominent among people of color. As melanin pigments in the skin slow the formation of Vitamin D, those with dark skin are even more disadvantaged than their light-skinned counterparts when living at northern latitudes. Studies within the past four years have shown that African Americans in the United States are more than ten times as likely as Caucasians to be Vitamin D deficient. African American women of childbearing age are 20 times as likely to be Vitamin D deficient. Diseases that have a higher level of prevalence among the African American population are also linked to Vitamin D deficiency, including heart disease, hypertension, type two diabetes, colorectal cancer, prostate cancer, cervical cancer, multiple sclerosis, obesity, and periodontal disease. Even breast cancer, which has a lower incidence among blacks, has a higher mortality rate among blacks.
These findings amount to a public health crisis, and current government standards for Vitamin D supplementation are woefully inadequate to meet the challenge. Many physicians today are unaware of the high level of Vitamin D deficiency in the African American community, or how supplementation with Vitamin D could effectively reduce mortality and the incidence of many prominent diseases in this community.
How Much Vitamin D to Take
How much Vitamin D is natural to the body? Twenty minutes summer sun, with arms and legs exposed, provides a light-skinned person 10,000 or more IUs of Vitamin D. (A dark-skinned person would receive the same amount in one and a half to three hours.) Based on this number, we can assume that such a dosage is safe for most people. Indeed, scientists have recently found that daily supplementation up to 10,000 IUs does not promote toxicity.
For most people, I find that 3000 IUs per day of vitamin D in the form of vitamin D3 is a good starting dosage for winter, with less in the summer depending on sun exposure. If you are heavy, dark-skinned, or a senior you will need more. However, the only way to know if you are getting the correct amount is to have a simple lab test done to determine Vitamin D blood levels.
Ask your doctor to test for Vitamin D (25-Hydroxy Vitamin D), or ask me to refer you to a lab. In reading your test results I like to see levels of 45-65 ng /mL in alignment with the research noted in this article. Most labs lag behind current research in their expectations for optimal Vitamin D. Test again after three months to assure adequate levels have been attained.
You may already be receiving small amounts of Vitamin D in your diet. Vitamin D is found in oily fish such as salmon, sardines, or cod liver oil. Also, milk and some cereals are supplemented with Vitamin D. Supplementation is low and inconsistent however, and many people avoid milk due to lactose intolerance. Cheese and yogurt are not supplemented. Also, the Vitamin D in milk is Vitamin D2 (ergocalciferol), which is 70% less effective than Vitamin D3 (cholecalciferol). For health optimization, we need adequate levels of D3.
The American Journal of Clinical Nutrition (and many others) criticize U.S. government standards for Vitamin D as "woefully inadequate," noting the substantial health benefits of Vitamin D supplementation. I agree with their criticism.
In Conclusion
While repeated sunburns raise the risk of skin cancer, depriving the body of Vitamin D by staying out of the sun completely or constantly applying suncreen, raises overall cancer risk by an even greater amount. When in the sun I like to protect my face with a hat, but allow arms and legs to receive a short sun-bath, then cover up with light clothing.
Enjoy the benefits of Mother Nature through sensible sun exposure, and supplement with Vitamin D to make sure you are getting what you need. I am available to answer personal questions regarding your Vitamin D intake and other health concerns in my office.
By Dr. James Otis, with Laura Cornell, PhD
References:
Badian, N. Journal of Learning Disabilities. 1984 March: 17(3): 129-36.
Davis, W. Vitamin D's crucial role in cardiovascular protection. Life Extension. 2007 September; 7 - 17.
Faloon, W. Should the president declare a national emergency? Life Extension. 2007 October 2007; 27 - 33.
Hollick, MF. Vitamin D deficiency. New England Journal of Medicine. 2007 July 19; 357(3): 266-81.
Lappe, JM, Travers-Gustafson D, Davies KM, Recker RR, Heanne RP. Vitamin D and calcium supplementation reduces cancer risk; results of a randomized trial. American Journal of Clinical Nutrition. 2007 June; 85(6): 1586-91.
McGrath, J. Journal of Steroid Biochemistry and Molecular Biology. 2004 March; 89-90 (1-5): 557 - 60.
American Journal of Clinical Nutrition. 2004 December; 80 (6 Supple): 1763S-6S.
American Journal of Clinical Nutrition. 2002 July; 76(1): 187-92.
