HOW PATIENTS MAY BENEFIT
Vitamin D is best known for helping promote bone mass by increasing calcium absorption from the intestines and maintain calcium levels in the blood. Subjects who do not get adequate Vitamin D every day may not adequately absorb calcium from the foods in their diet, leading the body to take calcium from bones.
Vitamin D supplementation is a topic of great interest within the medical and scientific communities because of its role in promoting healthy cellular growth and function.* Food sources of Vitamin D are limited and include egg yolks, liver, and fatty fish; milk is fortified with Vitamin D. The body can produce Vitamin D when the skin is exposed to sunlight. Residents of northern regions, older adults, and people who use sunscreen may produce less Vitamin D and may consider supplementing with high-potency supplements to ensure adequate D status.* A clinical review concluded that daily supplementation with 1000 IU of Vitamin D could have a major positive impact on public health (Garland 2006).
A growing body of evidence suggests that Vitamin D helps promote healthy cellular growth.* Vitamin D also may assist the immune system by helping to regulate T- and B-lymphocytes, supporting the ability of macrophages to defend the body, and promoting the synthesis of mononuclear cells*
STRUCTURE AND FUNCTION
The body synthesizes the active form of Vitamin D, 1,25-dihydroxyvitamin D3, from its two provitamin forms upon exposure to sunlight. The provitamins become active in the body after they are hydroxylated first in the liver and then in the kidney. The active form of Vitamin D has metabolic effects on cells and tissues.
In residents of northern climates, exposure to UV light may be inadequate to synthesize all of the Vitamin D required by the body. This becomes even more of a problem in winter months when there is less available sunlight and because people will have less skin exposed due to cold temperatures. The obvious solution is to increase Vitamin D intake from foods and supplements. Older individuals may especially benefit from higher levels of Vitamin D supplementation since it has been reported that Vitamin D absorption from the gastrointestinal tract decreases as a function of age. Dark-skinned individuals also synthesize relatively less Vitamin D from sun exposure, and are therefore excellent candidates for Vitamin D supplementation.
Mounting clinical evidence suggests that Vitamin D can have a major impact on not only bones but also immune health.* Variations in Vitamin D in the diet, exposure to sunlight, environmental conditions, gastrointestinal absorption, and genetic polymorphisms suggest that most adults should supplement with Vitamin D to ensure adequate intake and plasma concentrations.
For adults, take one (1) softgel or tablet daily, preferably with a meal, or follow the advice of your healthcare professional. As a reminder, discuss the supplements and medications you take with your healthcare providers.
Banwell, CM. 2006;12:2004-13.
Bao, BY, Ting HJ, Hsu JW, Lee YF. 2008 Mar 17; [Epub ahead of print]
Bao, BY, Yao J, Lee YF. 2006;27:1883-93. Epub 2006 Apr 19.
Beer, TM. 2006;12:2812-6.
Broe KE, Chen TC, Weinberg J, et al. J Am Geriatr Soc. 2007;55:234-9.
Chaimuangraj, S. Asian Pac 2006;7:136-9.
Cross HS. 2005;1:415-24.
Garland, C et al. Am J Publ Health. 2006; 96:9-18.
Gorham ED, Garland CF, Garland FC, et al. Am Journal Prevent Med. 2007;32:210-6.
Grant, WB. Prog Biophys Mol Biol. 2006;92:65-79. Epub 2006 Feb 28.
Heaney, R. et al. Am J Clin Nutr. 2003; 77:204-210.
Huth, PJ. J Dairy Sci. 2006; 89:1207-21.
Kemmis, CM. J Nutr. 2006;136:887-92.
Lim HS, Roychoudhuri R, Peto J, et al. 2006;119:1530-6.
McLeod, N. Aust Fam Physician. 2006;35:243-5.
Moan, J. Tidsskr Nor Laegeforen. 2006;126:1048-52.
Moon, S. Ann Hum Genet. 2006;70:226-36.
Ott, CD. 2006;29:21-31, quiz 32-3.
Sweeney, C. 2006;15:744-9.