Low Vitamin D Levels

Vitamin d milkThere has been extensive media coverage of recent studies linking vitamin D deficiencies to many common conditions and diseases, including cancer, osteoporosis, elevated blood pressure, infection, and cardiovascular and autoimmune disorders. The principal source of the vitamin is unprotected exposure of the skin to the sun’s UVB rays – the kind that also cause sunburn, premature aging of the skin, and skin cancer. And because sunscreen inhibits the body’s ability to make vitamin D, many of my patients are asking about getting adequate amounts without risking skin cancer.

A recent report by the International Osteoporosis Foundation shows that people around the world are suffering from low levels of the vitamin, with wide-ranging implications for health. It is important to become more knowledgeable about vitamin D and how to maintain adequate levels, and there are simple blood tests that can be performed by your physician to determine vitamin D levels.

Most fair-skinned people can generate up to 10,000 units of vitamin D in 15 minutes of unprotected exposure to the sun. Darker-skinned people might require up to 40 minutes of exposure to reach those levels because of increased melanin in the skin, a natural UV protector. Because the body self-regulates the production of the vitamin, it is nearly impossible to overdose to toxic levels.

The toxic dose may be in the millions of units, and people who have had side effects usually have been taking over 40,000 units a day. There have been some reports of overdose due to poorly manufactured vitamins containing far more vitamin D than listed on the label.

The established minimum daily requirement for vitamin D is 400 units, but it is estimated that we get only 100 units from food sources, even though a number of common foods, such as milk and orange juice, are fortified with vitamin D. While some dairy products and fatty fish, like salmon, mackerel, tuna, and herring, are rich sources of the vitamin, it is difficult to get enough nutritionally. 

If you have an outdoor-oriented lifestyle, you’re probably getting enough. But if you spend most daylight hours indoors, use sun block consistently, or are dark-skinned, you may need to boost your vitamin D levels through supplements. Patients with abnormal calcium levels or kidney problems should carefully discuss vitamin D supplementation with their doctor.

Dermatologists recommend getting vitamin D through diet and supplements manufactured by reputable sources rather than through unprotected sun exposure. The American Academy of Dermatology (AAD) has recently revised its position on vitamin D, recommending a daily dose of 600 units for most people and suggesting up to 1,000 units a day for those at risk of certain conditions. Given the safety of vitamin D, it would not be surprising that even higher doses may be recommended in the future.

But don’t compromise your skin health with unprotected sun exposure just to get vitamin D. Even “just” 15 minutes a day in the sun, over a lifetime, could severely damage skin and boost the odds of developing skin cancer. And beware of the “Get Your Healthy Tan” ads from tanning salons exploiting news on vitamin D deficiency, hoping to lure customers. The World Health Organization recently deemed tanning beds and UV radiation as human carcinogenic agents.

As we are learning, vitamin D is crucially important to overall health, but the bottom line is this: keep using sunscreen and protecting yourself from UV exposure, and take appropriate vitamin D supplements, which are generally inexpensive and easy to find. 

Published on 08/13/2009 | Last updated on 10/18/2018