The Princeton Longevity Center Medical News
Tip # 6- Get Some Sun
Vitamin fads come and go. Most of the claims that are made for them just don’t stand up to scientific scrutiny. The one exception appears to be Vitamin D.
Vitamin D deficiency is increasingly linked to a wide range of medical problems. People with low levels have twice the risk of dying from a heart attack or strokes. Low vitamin D can cause kidney stones, raise the blood pressure and is associated with Metabolic Syndrome, a pre-diabetic condition. High levels of vitamin D have been associated with protection against some cancers and Alzheimer’s Disease.
Vitamin D is also crucial for maintaining good bone health. The leading cause of admissions to nursing home in the US is osteoporosis. At Princeton Longevity Center, we find that more than 35% of BOTH men and women over the age of 40 have low bone density (osteopenia) and are at risk for osteoporosis. Virtually all of these people have low blood levels of Vitamin D. Some studies have found that as much as 70% of the population in the US is vitamin D deficient.
Vitamin D comes from both our diet and from sun exposure. Very few foods contain significant levels of Vitamin D. Current recommendations for daily Vitamin D intake are usually in the range of 200 to 600 units per day. Fish such as salmon, mackerel and tuna, along with fish liver oils are excellent sources of Vitamin D. A serving of fish may have 300 to 400 units of Vitamin D and a tablespoon of Cod Liver Oil has about 1300 units. Vitamin D is often added to certain foods such as dairy, yogurts, orange juice or cereal. These are usually labeled as “fortified with Vitamin D”. Even so, the usual dose of Vitamin D in a glass of milk is only about 100 units. So it would take more than a quart of milk per day or a steady diet of fish just to maintain a minimal blood level of vitamin D.
Vitamin D is synthesized in the skin with exposure to the UV-B rays in sunlight. This is normally our major source of Vitamin D. In general, it takes about 10-30 minutes of exposure to midday sunlight to make the Vitamin D you need each day. Of course, this also affected by other factors such as latitude, cloud cover, clothing and wearing sunblock. UV-B does not penetrate glass. So exposure to sunlight inside your house or car will not result in Vitamin D production. Those who live in higher latitudes where sun exposure is weaker, or those who are rarely outdoors during daylight hours, may need even more exposure to maintain adequate levels. If you live north of Boston you can not get sufficient sunlight, regardless of time spent outside, to maintain normal Vitamin D levels from November through February. Only those living south of South Carolina are able to get adequate sun exposure throughout all 12 months of the year.
Taking a daily supplement of 400-800 units of Vitamin D will help you maintain an adequate level of this crucial nutrient.