Protecting Your Health With Vitamin D
by Curtis Walcker
This fat-soluble vitamin is best known for its roles in preventing rickets and maintaining proper levels of calcium in the blood. The "sunshine vitamin" is generally acquired by the body in two ways:
• exposure to the sun's ultraviolet (UV) rays
• dietary intake
The latest research reports are announcing ways that vitamin D may be involved in protecting against the development and progression of several common diseases. Unfortunately, many of these new disease connections are being made because of newly found widespread deficiencies of vitamin D in the U.S. population.
The current recommended daily intakes (RDIs) for vitamin D are 200 IU daily for those up to 50 years of age, 400 IU daily for those between 51 and 70, and 600 IU daily for those over 70. It has generally been thought that if you get enough time in the sun and eat a diet with foods like vitamin D-fortified milk, deficiency will not be a problem.
However, many factors come into play when it comes to your body receiving UV exposure to the sun and processing that into vitamin D in the body. Things like time spent in the sun, age, genetics, use of UV-blocking sunscreens, and even where you live can all have an effect.
In fact, much of what is being discovered about vitamin D has come about from population studies that have correlated increased risks of certain diseases to populations living in more northern latitudes that receive less sunshine. In attempts to correct deficiencies, it is being found that the RDIs may not be sufficient. The topic of officially increasing vitamin D intake recommendations is current under review.
A link between vitamin D and several types of cancers has been known since as early as the 1940's, but the mechanisms through which it works are now under rigorous investigation. In a prostate cancer study, researchers found that vitamin D may link to a gene called glucose-6-phosphate dehydrogenase (G6DP), which release antioxidant enzymes that protect against DNA damage (1). A role for vitamin D in combination with calcium has been identified for colon cancer as well. In patients that consumed sufficient amounts of vitamin D and calcium, expression of the biomarkers E-cadherin and betacatenin associated with the disease was significantly different than those with low intakes(2).
A large breast cancer study demonstrated vitamin D's anti- proliferative effects on hormone-receptor-positive cells (3). Higher levels of vitamin D intake were associated with 24 percent risk reductions in these types of tumors. In a study following 3,299 patients with fatal cancers for nearly eight years, those with the highest blood levels of vitamin D were 55 percent less likely to die from their cancer (4).
Research on vitamin D on cardiovascular disease was just as impressive. Vitamin D intake was linked to fewer heart-related deaths, lessened heart attack risks, and better health of the arteries. For the first time ever, it was demonstrated that higher levels of vitamin D are associated with lower all-cause and cardiovascular mortalities (5).
A blood level of 20 ng/mL was advised, and intakes of about 3,000 IU of vitamin D per day were needed to raise a low level to this level. Patients in this study with the lowest average blood levels of vitamin D had 122 percent increase in the risk of cardiovascular mortality compared to the group with the highest average levels.
Potential mechanisms of action were discussed in two other recent studies (6,7). Vitamin D has been proposed to improve smooth muscle health, reduce inflammation, reduce vascular calcification, and improve blood pressure.
Additional new areas of vitamin D research have included diabetes, longevity, skin health, mood, and Parkinson's disease. In two separate studies involving children, development of diabetes was correlated to vitamin D status (8,9).
Further supporting a study published in 2007 regarding vitamin D's association with telomere length and the slowing of the aging process and the onset of age-related diseases (10), a new study looked at data taken from the National Health and Nutritional Examination Survey (NHANES III) (11). This study took into account a population of 13,331 health men and women over 8.7 years, and found that low levels of vitamin D were associated with increased risk for all causes of mortality, as well as a host of other health conditions.
Vitamin D supplementation has been found to improve skin conditions such as itching, redness, and scaling through increased cathelicidin production; an antimicrobial peptide (12).
Also, low levels of vitamin D have been reported on recently to be associated with mood disorders (13) and the development of Parkinson's disease (14).
1. Bao BY, Ting HJ, Hsu JW, Lee YF. "Protective role of 1 alpha, 25-dihydroxyvitamin D3 against oxidative stress in nonmalignant human prostate epithelial cells." Bao BY, Ting HJ, Hsu JW, Lee YF. Int J Cancer. 2008 Jun 15;122(12): 2699-706.
2. A. Thomas, C. Dash, R.M. Bostick, Associations of calcium and vitamin D with E-cadherin and β-catenin expression in normal- appearing rectal tissue; markers of adenomatous polyps II (MAP II) case-control study, American Association for Cancer Research Annual Meeting, 13 April 2008, Abstract 565.
3. Blackmore KM, Lesosky M, Barnett H, Raboud JM, Vieth R, Knight JA. "Vitamin D from dietary intake and sunlight exposure and the risk of hormonereceptor-defined breast cancer." Am J Epidemiol. 2008 Oct 15;168(8):915-24. Epub 2008 Aug 27.
4. Pilz S, Dobnig H, Winklhofer-Roob B, Riedmüller G, Fischer JE, Seelhorst U, Wellnitz B, Boehm BO, März W. "Low serum levels of 25- hydroxyvitamin D predict fatal cancer in patients referred to coronary angiography." Cancer Epidemiol Biomarkers Prev. 2008 May;17 (5):1228-33. Epub 2008 May 7.
5. Dobnig H, Pilz S, Scharnagl H, Renner W, Seelhorst U, Wellnitz B, Kinkeldei J, Boehm BO, Weihrauch G, Maerz W. "Independent association of low serum 25-hydroxyvitamin d and 1,25- dihydroxyvitamin d levels with all-cause and cardiovascular mortality." Arch Intern Med. 2008 Jun 23;168(12):1340-9.
6. Giovannucci E, Liu Y, Hollis BW, Rimm EB. "25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study." Arch Intern Med. 2008 Jun 9;168(11):1174-80.
7. Melamed ML, Muntner P, Michos ED, Uribarri J, Weber C, Sharma J, Raggi P. "Serum 25-hydroxyvitamin D levels and the prevalence of peripheral arterial disease: results from NHANES 2001 to 2004." Arterioscler Thromb Vasc Biol. 2008 Jun;28(6):1179-85. Epub 2008 Apr 16.
8. Zipitis CS, Akobeng AK. "Vitamin D supplementation in early childhood and risk of type 1 diabetes: a systematic review and meta- analysis." Arch Dis Child. 2008 Jun;93(6):512-7. Epub 2008 Mar 13. Review.
9. Svoren BM, Volkening LK, Wood JR, Laffel LMB. "Significant Vitamin D Deficiency in Youth with Type 1 Diabetes Mellitus." Journal of Pediatrics. 2009;154:132-134.
10. Richards, B. et al. "Higher Serum Vitamin D Concentrations are Associated with Longer Leukocyte Telomere Length in Women." American Journal of Clinical Nutrition 2007;86:1420-1425.
11. Melamed ML, Michos ED, Post W, Astor B. "25-hydroxyvitamin D levels and the risk of mortality in the general population." Arch Intern Med. 2008 Aug 11;168(15):1629-37.
12. Hata TR, Kotol P, Jackson M, Nguyen M, Paik A, Udall D, Kanada K, Yamasaki K, Alexandrescu D, Gallo RL. "Administration of oral vitamin D induces cathelicidin production in atopic individuals." J Allergy Clin Immunol. 2008 Oct;122(4):829-31.
13. Hoogendijk WJ, Lips P, Dik MG, Deeg DJ, Beekman AT, Penninx BW. "Depression is associated with decreased 25-hydroxyvitamin D and increased parathyroid hormone levels in older adults." Arch Gen Psychiatry. 2008 May;65(5):508-12.
14. Evatt ML, Delong MR, Khazai N, Rosen A, Triche S, Tangpricha V. "Prevalence of vitamin d insufficiency in patients with Parkinson disease and Alzheimer disease." Arch Neurol. 2008 Oct;65(10): 1348-52.