Why and how much Vitamin D do you need to take?

Our bodies convert ultraviolet B rays into Vitamin D. But, most people, except for residents of Florida and Hawaii, do not get enough sun exposure. Lack of exposure to sun due to sun screen usage, skin pigmentation, higher latitudes, clothing , spending many hours at home and pollution has created a wide spread vitamin D deficiency. Even in sunny Northern California, more than 80% of our patients had lower than normal levels of vitamin D. Vitamin D deficiency has been linked to many chronic illnesses, such as depression, heart disease, multiple sclerosis, diabetes and cancers. A lack of vitamin D is also notorious for causing rickets. Remember when we were forced to take cod liver oil every day as kids? Yuck! Since then, milk has been fortified with vitamin D and the practice of the force-feeding of the stinky cod liver oil been rendered obsolete.

Food sources of vitamin D are fish liver oil, the flesh of fatty fish, the fat from seals and polar bears (yummy!), and fortified milk. Unfortunately, many people do not drink enough milk and avoid eating polar bears, plus it’s not clear that even if you do, you’ll get a sufficient level in the blood. So, it’s obvious that we need to supplement vitamin D but then how much?

The official recommendation is 200 to 600 units per day, depending on age. However, most people who take that much vitamin D still have levels below normal. While officials of the US Advisory Board are waiting for more data to support increasing the recommended dosage, we suggest people take at least 1000 units, and up to 2000 units in the winter months. It is cheap and safe and those doses do not have any side effects. In the last several years, the market for vitamin D skyrocketed from 50 million to 250 million. Clearly, I’m not the only doctor who recommends taking adequate vitamin D daily to normalize its level in the bloodstream.

I know this advice can be confusing. For years, we were told that going under the sun unprotected would give us skin cancer, and now we’re hearing that protection will give us a vitamin D deficiency. The best solution is to continue with the precautionary measures, but to take supplements with meals.
--Dr M