Vitamin D is actually a prohormone, and its presence affects many organs, such as brain, heart, skin, testicles and ovaries, prostate gland, and breast tissue. In the parathyroid glands, active metabolites of vitamin D are responsible for calcium uptake. Therefore, vitamin D is vital in calcium metabolism and bone strength, regardless of the amount of calcium we take. Vitamin D deficiency results in rickets (with bowed legs) and increased risk of bone fractures. Vitamin D insufficiency will result in osteomalacia, characterized by softening of the bones and muscle pain. Chronic vitamin D deficiency will lead to secondary hyperparathyroidism (the gland will work over-time, trying to compensate for the low vitamin D level in the body). This eventually will lead to osteoporosis.
There are two forms of vitamin D measured in the blood: 25(OH) D (calcidiol) and 1,25 hydroxyvitamin D (1,25{OH} 2D) (calcitrol). Because of its greater reliability, 25(OH)D (calcidiol) is now the favored form of measurement of vitamin D in the body. The optimal level of serum 25(OH)D is 35-55 ng/ml. Some physicians recommend a higher range.
It is now believed toxicity due to excess vitamin D is unlikely in most patients without health issues, with daily consumption of 40,000 IU/day (international units) leading to toxicity. The best source of vitamin D is sunlight, with daily sunlight exposure of 15 minutes recommended. In places such as Southern California, sunlight exposure can active vitamin D year around. However in colder areas, sunlight exposure is insufficient from November through February.
The longtime government recommendation for vitamin D intake for adults was set arbitrarily at 400 IU/day. This is perhaps due to historical precedent that a teaspoon of cod liver oil, a traditional source of vitamin D, delivers approximately 400 IU of vitamin D. We now know this recommendation is inadequate for almost every one. Unfortunately, the amount of vitamin D in dairy products is not high enough. One may get enough calcium from dairy products (and that is hard to do), but almost impossible with regular food intake of dairy products. The best source of natural vitamin D is cod liver oil, with one table spoon delivering 1360 IU. Yuck!
Please note vitamin D supplements are available in two forms: vitamin D2 (ergocalciferol) and D3 (cholecalciferol). The current theory is vitamin D3 is a better form of supplementation than vitamin D2.
These are the current recommendations for vitamin D supplementation:
Vitamin D deficiency (rare) (25(OH)D level below 20) vitamin D 50,000 IU/day once a week for three months with repeat level
Vitamin D insufficiency (common) (levels between 20-30) vitamin D 2000- 5000 IU/day until levels reach 40-50 ng/ml. This is a general guide line and considerable variability in response to vitamin D supplementation exists between patients. However, the current RDA of 400 IU/day, found in most daily vitamin supplements, is clearly inadequate.
Of course every patient is different, and the regimen should be customized to each person. My goal is to educate you about this important vitamin and the current thinking about supplementation.
Please have your physician obtain a vitamin D level and see what your levels are. You may be surprised!
Michael A. Jazayeri, M.D. is a board certified plastic surgeon in Santa Ana with over 10 years of experience in both cosmetic and reconstructive surgery. His office is located in Orange County, California. To schedule a consultation, please call (714) 834-0101.