Not long ago, vitamin D was only considered essential for strong bones and teeth. Now it’s known to have wide-ranging functions throughout the body – hence the importance of getting regular sun exposure or taking vitamin D supplements.
But relying only on D supplements and avoiding the sun could be a big mistake, because the sun’s benefits go well beyond vitamin D.
In the most recent discovery, researchers from Georgetown University have found a new mechanism triggered by the sun which helps boost the immune system. . .
The new benefit doesn’t come from the sun’s ultraviolet rays, but from its blue rays.
Sunlight Turbocharges T Cells
The team of scientists led by Dr. George Ahern subjected blood cell cultures from mice and humans to blue light. Then they traced the molecular paths and configurations the cells followed.
They found blue light caused T cells to move faster. These cells play a crucial role in the immune system, seeking out pathogens and killing them.
Dr. Ahern explains, “T cells, whether helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response. This study shows that sunlight directly activates key immune cells by increasing their movement.”
He went on to describe how the mechanism works.
“We found that sunlight makes hydrogen peroxide in T cells, which makes the cells move. And we know that an immune response also uses hydrogen peroxide to make T cells move to the damage.”
A large proportion of the body’s T cells are found in the skin — twice as many as those circulating in the blood. Blue light is able to reach the second layer of the skin, the dermis, to activate these cells.
This new immune system connection is not the only benefit of sunlight not related to vitamin D.
Avoiding The Sun is as Dangerous as Smoking
Twenty-year data was collected on the sunbathing habits of 29,518 Swedish women. The research, published last October, found those subjected to the most sun exposure had half the death rate of those who avoided the sun.
The researchers wrote that, “Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking.”
If true, this is frontpage news.
Pelle Lindqvist, M.D., the lead author of the study, put it like this: “We know in our population, there are three big lifestyle factors [that endanger health]: smoking, being overweight, and inactivity. Now we know there is a fourth — avoiding sun exposure.”
Slows Weight Gain and Development of Diabetes
Consultant dermatologist Dr. Richard Weller and his research team from the University of Edinburgh have conducted a number of studies on the benefits of sunlight.
In 2016 he published a paper called Sunlight Has Cardiovascular Benefits Independently of Vitamin D.
He writes that sun exposure can trigger the release of nitric oxide. This dilates blood vessels, lowers blood pressure and reduces the risk of heart attacks and stroke.
Dr. Weller was also part of a collaborative research effort that tested ultraviolet exposure on obese mice. Natural sunlight contains large amounts of UV rays, as you probably know. Dr. Weller’s group found that UV exposure slowed weight gain and the development of type 2 diabetes. These benefits were independent of vitamin D.
The researchers again believed that increased nitric oxide production explained the results.
According to one of the scientists, Dr. Martin Feelisch of Southampton University, “Our observations indicate that the amounts of nitric oxide released from the skin may have beneficial effects not only on heart and blood vessels but also on the way our body regulates metabolism.”
Sunlight Affects Our Genes
In 2015, researchers from Cambridge University found that the expression of over a quarter of our genes varies from one season to the next.
In the winter, inflammatory immune-system genes are up-regulated, whereas in the summer, anti-inflammatory genes are increased.
Since inflammation is connected to almost every chronic health condition, it’s possible that exposure to sunlight prompts an anti-inflammatory response.
Back to Dr. Weller:
“As well as nitric oxide, it also appears that sunlight alters the way that our genes behave. I think there will be other factors that we have yet to discover. There is a correlation between more sun and less disease in a variety of conditions.”
Many researchers now believe the “keep out of the sun” mantra has been overdone. We all need to be regularly exposed to the sun for overall good health. Just make sure you do this safely and don’t burn.