Sunlight is a good source of vitamin D
Stress for Success
March 11, 2008


How much, if any, unprotected sunshine is good for you?

How much sunshine puts you at risk for skin cancer? Does too little rob you of its health-enhancing benefits?

Since most living things require sunshine it only makes sense that our bodies do, too.

"Modern … work routines have curbed our exposure to sunlight," says Daniel Kripke, psychiatry professor, University of California at San Diego. He found San Diegans average less than an hour a day outside, which may be bad for their health.

Edward Giovannucci of Harvard’s School of Public Health worries that "Our scrupulous avoidance of the sun may have inadvertently led to widespread vitamin D deficiencies."

Michael Holick, world-renowned vitamin D expert and professor of medicine at Boston University, adds, "The message from dermatologists never to expose yourself directly to sunlight is itself hazardous to your health. It has put the population at risk for vitamin D deficiency," especially the frail elderly and dark-skinned people living at high latitudes or in cloudy climates.

Last week I wrote about mounting research regarding the role of sunlight and cancer development. Briefly, if you live at high latitudes, you're more likely to suffer and die from cancers of the colon, pancreas, prostate, ovaries and breast. Raising blood levels of vitamin D reduces the incidence of colorectal cancer by half. Also, women with the highest amounts of vitamin D had the lowest risk of breast cancer.

A 2006 study led Holick compared tumor growth in mice with low levels of vitamin D and mice with high levels. "The tumors took off in the vitamin D-deficient mice." By the study's end, they were 80% larger than the ones in the vitamin D-sufficient mice.

The evidence of vitamin D's effects is so strong that some scientists say the best thing to protect against cancer, apart from not smoking and avoiding excessive alcohol, is to get enough vitamin D. Unfiltered sunlight for at least a few minutes daily fights heart disease, cancer, autoimmune disorders and even depression. Some research suggests it may even add seven years to your life!

NIH sponsored a conference on this topic in September. Barbara Gilchrest, chief of dermatology at Boston University said, "There’s still no consensus on the optimal amount. But there’s consensus on how people should get more of the vitamin, through supplements ..."

Holick agrees that supplements would be the easiest solution. He takes 1400 IU per day himself. But he still promotes sunlight because there are at least three other photoproducts not available in supplements. He doesn’t endorse tanning but says, "You can get sufficient vitamin D ... by exposing your arms and legs to the midday sun for only 10 to 15 minutes."

But those who are fair-skinned, tan poorly and freckle easily are vulnerable to burning. Gilchrest says, "For them, even a little sun carries a much greater risk of skin damage. (They’re) already getting all the sun they need from their daily activities.”

Stay tuned for additional research. In the meantime, if you tan well, consider small amounts of daily direct sunlight to function more healthfully and maybe to live longer.

Jacquelyn Ferguson, M. S., of InterAction Associates, is a trainer and a Stress Coach. E-mail her at www.jackieferguson.com with your questions or for information about her workshops (like Slow Down You Move Too Fast at FGCU on March19) on this and other topics and to invite her to speak to your organization.