Vitamin D might be one of the world's most ancient vitamins, with traces found in million-year-old fossils, according to "Nutrition Review." The ability of your body to convert sunshine into vitamin D3 is well established. Also accepted is vitamin D3's role in maintaining healthy bones and teeth, and that deficiencies might cause serious medical issues. But, as of 2011, the verdict is out on how much vitamin D3 you really need.
Role of Vitamin D3
Before vitamin D3 can be used by your body, it goes through several complex changes involving the liver and kidneys. The kidneys excrete the amount of the active form of vitamin D3 your body needs, according to the serum levels of calcium and phosphorus in your blood. Calcium and phosphorus are vital in maintaining the right amount of mineralization in your bones and teeth. Without vitamin D3, demineralization would occur, causing possible disease or pain. Many of the body's cells have vitamin D3 receptors, suggesting that vitamin D3 also plays roles in many other functions in the body, such as insulin secretion, immunity, cell differentiation, blood pressure regulation and many others not yet established, according to the Linus Pauling Institute.
Vitamin D3 Deficiencies
Vitamin D3 deficiency might result from numerous conditions, including rickets, which is softening of the bones, mainly seen in children; osteomalacia, or bone pain caused by loss of bone mass, mainly in adults; osteoarthritis, the breakdown of cartilage due to low levels of vitamin D3; rheumatoid arthritis, an autoimmune disease in which the body sees the linings of joints as foreign bodies and attacks them due to low levels of vitamin D3; and muscle pain and weakness, also linked to low vitamin D3 levels.
Dosage Dilemma
The current recommended dietary allowance for vitamin D is 600 IU per day for ages 1 through 70. For infants, the RDA is 400 IU per day, and for the elderly, it is 800 IU per day. However, it is felt that these recommendations require review as they might not be sufficient to maintain adequate levels. An article in the "Journal of Nutrition" says full-body exposure in the sun at its peak, such as in the summer at noon, for 10 to 15 minutes, will produce around 20,000 IU of circulating vitamin D3. The article goes further to say that circulating levels of vitamin D3 below 1,200 IU might be considered deficient. As with all supplements, consult your doctor first.
Vitamin D3 and Pregnancy
Another dilemma appears with pregnant women, according to a study in "The American Journal of Clinical Nutrition." Currently, the RDA for pregnant women is 400 to 600 IU per day. However, if you already have low levels of vitamin D3, as the study says is quite common, these suggested daily amounts are not sufficient to keep up with the daily needs of you and your growing baby. This might lead to deficiencies. The article recommends that before taking vitamin D3 supplements during pregnancy, ask your doctor to test your levels before prescribing an adequate vitamin D3 dosage.
References
- "Nutrition Reviews"; "Vitamin D -- a D-Lightful Health Perspective"; Michael Holick; September 2008
- Linus Pauling Institute: Micronutrient Information Center
- Wiley.com: Arthritis and Rheumatism -- Vitamin D intake is inversely associated with rheumatoid arthritis -- Results from the Iowa Women's Health Study
- "Annals of Internal Medicine"; "Relation of Dietary Intake and Serum Levels of Vitamin D to Progression of Osteoarthritis of the Knee among Participants in the Framingham Study"; Timothy McAlindon et al; September 1996
- "Journal of Nutrition"; "Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D"; B.W. Hollis; February 2005
- "American Journal of Clinical Nutrition"; "Assessment of dietary vitamin D requirements during pregnancy and lactation"; Bruce Hollis et al; May 2004
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