Sunlight Slows Weight Gain And Diabetes
As reported by ScienceDaily (10/14) - Sunshine May Slow Weight Gain, Diabetes Onset, Study Suggests
Exposure to moderate amounts of sunshine may slow the development of obesity and
diabetes, a study suggests. Scientists who looked at the effect of sunlight on
mice say further research will be needed to confirm whether it has the same
effect on people. The researchers showed that shining UV light at overfed mice
slowed their weight gain. The mice displayed fewer of the warning signs linked
to diabetes, such as abnormal glucose levels and resistance to insulin.
The beneficial effects of UV treatment were linked to a compound called nitric
oxide, which is released by the skin after exposure to sunlight. Applying a
cream containing nitric oxide to the skin of the overfed mice had the same
effect of curbing weight gain as exposure to UV light, the team found.
Vitamin D is produced by the body in response to sunlight and often lauded for
its health benefits -- did not play a role, the study found. The team says the
new findings add to the growing body of evidence that supports the health
benefits of moderate exposure to the sun's rays. Previous studies in people
have shown that nitric oxide can lower blood pressure after exposure to UV
lamps. The results should be interpreted cautiously, the researchers say, as
mice are nocturnal animals covered in fur and not usually exposed to much
sunlight. Studies are needed to confirm whether sunshine exposure has the same
effect on weight gain and risk of diabetes in people.
Researchers at the Telethon Kids Institute in Perth, Western Australia, led the
study in collaboration with the Universities of Edinburgh and Southampton. Dr
Shelley Gorman, of the Telethon Kids Institute and lead author of the study,
said: "Our findings are important as they suggest that casual skin exposure to
sunlight, together with plenty of exercise and a healthy diet, may help prevent
the development of obesity in children." "These observations further 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," Dr Martin Feelisch, Professor of Experimental Medicine
and Integrative Biology at the University of Southampton, added.
Dr Richard Weller, Senior Lecturer in Dermatology at the University of
Edinburgh, said: "We know from epidemiology studies that sun-seekers live
longer than those who spend their lives in the shade. Studies such as this one
are helping us to understand how the sun can be good for us. We need to
remember that skin cancer is not the only disease that can kill us and should
perhaps balance our advice on sun exposure."
The research is published in the journal Diabetes.
The above story is based on materials provided by University of Edinburgh
Mixed Messages On Sun Exposure
Vitamin D is a steroid vitamin, a group of fat-soluble prohormones, which
encourages the absorption and metabolism of calcium and phosphorous. People who
are exposed to normal quantities of sunlight do not need vitamin D supplements
because sunlight promotes sufficient vitamin D synthesis in the skin.
For decades we have been told to stay out of the sun, to wear hats and cover
ourselves with sun block to protect against skin cancer and also significantly
reducing our levels of vitamin D. Add to that a growingly sedentary lifestyle
where we and our children spend more time indoors either watching TV or in
front of a computer monitor, and it is not surprising that millions of people
have excessively low levels of vitamin D in our system.
Then we are told that sunlight can rapidly make up for any vitamin D shortfall,
while at the same time the American Academy of Dermatology continues to
recommend that the public obtain vitamin D from nutritional sources and dietary
supplements, and not from unprotected exposure to ultraviolet radiation because
of the skin cancer risk, and we despair.
Telling people to get their vitamin D from just food and supplements obviously
does not work. People have been told that for the last twenty years and vitamin
D deficiency or insufficiency has increased significantly. It is estimated that
50% of American elderly women consume far less vitamin D in their diet than
recommended. Consequently, vitamin D deficiency is a serious problem among the
elderly in the USA.
It is understandable why a dermatologist, who is in direct contact with skin
cancer patients, advises people to stay out of the sun. However, millions of
people are and will develop other very serious diseases because their vitamin D
levels are too low. Skin cancer is one factor, but there are many other
• Why is the current policy of telling people to get just their vitamin D from
nutritional sources not working?
• Is the current vitamin D problem greater than the skin cancer problem?
• Is it possible to estimate what the impact of recommending 15 minutes twice a
week of sun exposure would be on skin cancer numbers, and the health benefits
from a resulting lower incidence of vitamin D deficiency in the population?
Some health authorities are starting to change their recommendations. Here is a
quote from the Cancer Council, Australia (2009): "Sun exposure is the cause of
around 99% of non-melanoma skin cancers and 95% of melanomas in Australia.
However, exposure to small amounts of sunlight is also essential to good
health. A balance is required between avoiding an increase in the risk of skin
cancer by excessive sun exposure and achieving enough exposure to maintain
adequate vitamin D levels."
Info from Medical News Today 8/09