Skip to content

Tag: sun exposure

Published on Leave a comment on Are We Looking At Sunlight and Health the Wrong Way?

Are we looking at vitamin D and sunlight the wrong way? Back in 2016 I posted about the results of a long-running Swedish study that made me rethink everything I knew about sunlight and health. (The prevailing view of dermatologists at the time and now is: to always use sunscreen if going outdoors in order to lower the risk of skin cancer. In other words, that sunlight is always harmful.)

The Swedish study followed women for 20 years and found that: Women who had more sunlight exposure experienced a lower mortality rate than women who avoided sun exposure. However, they were at an increased risk of skin cancer. But those with more sun exposure lived longer due to a decrease in heart (cardiovascular) disease and other noncancer reasons. And the most surprising finding: Nonsmokers who avoided sun exposure had a similar life expectancy as smokers with the highest sun exposure. In other words: avoidance of sun exposure = cigarette smoking when looking at life expectancy. And the results of sun exposure was dose-dependent, with the more, the better for longer life expectancy.

The researchers suggested that  a person's vitamin D levels might be just a marker of sun exposure, which other studies and articles now also suggest. So while we measure vitamin D levels in studies, maybe we should instead be looking at sunlight exposure.

Since then I read more studies that found other benefits of sunlight exposure, such as sunlight having low levels of "blue light" which energizes T cells. T cells are a type of white blood cell, are part of the immune system, and help protect the body from infection and cellular abnormalities (cancer). An earlier study found that exposing skin to sunlight may help to reduce blood pressure and thus cut the risk of heart attack and stroke.

This year I read the following two nicely written articles about this whole issue, both a little different - so worth reading both to get a good idea about the research and the debate.

1) From Outside: Is Sunscreen the New Margarine?

2) From Elemental Medium: What If Avoiding the Sun Is Bad for You?

And once again, a link to the 20 year Swedish study, from the Journal of Internal Medicine: Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort

Published on

Another study finding a benefit of coffee consumption - this time linked to a lower rate of MS. Keep in mind that numerous studies have shown a strong association of higher sunlight exposure (especially in childhood), and living at lower latitudes (more sunlight exposure) with lower rates of multiple sclerosis. From Science Daily:

Can coffee reduce your risk of MS?

Drinking coffee may be associated with a lower risk of developing multiple sclerosis (MS), according to a study released today that will be presented at the American Academy of Neurology's 67th Annual Meeting in Washington, DC, April 18 to 25, 2015."Caffeine intake has been associated with a reduced risk of Parkinson's and Alzheimer's diseases, and our study shows that coffee intake may also protect against MS, supporting the idea that the drug may have protective effects for the brain," said study author Ellen Mowry, MD, MCR, with Johns Hopkins University School of Medicine in Baltimore and a member of the American Academy of Neurology.

For the study, researchers looked at a Swedish study of 1,629 people with MS and 2,807 healthy people, and a U.S. study of 1,159 people with MS and 1,172 healthy people. The studies characterized coffee consumption among persons with MS one and five years before MS symptoms began (as well as 10 years before MS symptoms began in the Swedish study) and compared it to coffee consumption of people who did not have MS at similar time periods. The study also accounted for other factors such as age, sex, smoking, body mass index, and sun exposure habits.

The Swedish study found that compared to people who drank at least six cups of coffee per day during the year before symptoms appeared, those who did not drink coffee had about a one and a half times increased risk of developing MS. Drinking large amounts of coffee five or 10 years before symptoms started was similarly protective.

In the US study, people who didn't drink coffee were also about one and a half times more likely to develop the disease than those who drank four or more cups of coffee per day in the year before symptoms started to develop the disease.