|
|
(HealthNewsDigest.com) – This is the time of year when everyone is worried about gaining weight because of too many holiday parties and too much tempting food. Researchers at the University of Alberta have suggested an intriguing hypothesis for winter weight gain – not too many parties but too little sunlight.
Though this line of research is in its infancy, the concept is fascinating. Dysfunctional white adipose tissue (WAT) is connected to the development of obesity, diabetes and heart disease. Belly fat (intra-abdominal visceral WAT) is thought to increase one’s risk for all of these conditions. But subcutaneous WAT, found directly under the skin, making up 80% of body’s fat, also contributes to the risk for obesity and other chronic diseases. Because subcutaneous WAT is widespread over the body, it is this type of fat that may react to sunlight exposure.
When humans are exposed to ultraviolet light, they are able to make vitamin D and their skin darkens or turns red from sunburn, but little UV light actually penetrates the skin. Blue/green light waves are different. Though as much as 40% of blue/green light is reflected, scattered, or absorbed in the outer skin layers, 1% to 5% of blue/green light is able to pass through the outer skin and reach the subcutaneous fat. This is where Peter Light (no pun intended, it is his real name) and his colleagues discovered some very interesting findings.
When fat cells under the skin are exposed to blue light wavelengths, lipid (fat) droplets reduce in size and are released from the cells. Our fat cells simply don’t store as much fat when the body is regularly exposed to sunlight. In the winter, we typically get insufficient sunlight and even in milder weather wearing clothes reduces skin exposure. If we need sunlight to release fat from cells, limiting sun exposure may be promoting fat storage and contributing to the typical winter weight gain many people complain about.
There is a great deal of population research showing that our current generation weighs more than our parents or grandparents. Changes in the way we work and lead our lives has inadvertently limited the amount of healthy sunshine we are regularly exposed to. Could this be another contributor to our growing obesity epidemic?
Light does regulate our sleep/wake cycle, so it is possible that light may also regulate the amount of fat we burn or store. Our ancestors may have gained more weight in the winter when light was scarce and burned it off in the summer sunshine.
Though this research is in its early stages it did identify a novel sunlight pathway in human subcutaneous fat that is sensitive to light that penetrates into the body on a sunny day. This may open new avenues of understanding of how fat in the body is regulated and may lead to public health recommendations that include sufficient exposure to sunlight. In contrast, too little sunlight could be a contributing factor in weight gain and disease risk.
What does this all mean? Weight gain and obesity are complex problems and there are many contributing factors, one of which may be sunlight.
© NRH Nutrition Consultants, Inc.
Jo-Ann Heslin, MA, RD, CDN is a registered dietitian and the author of 30 books.
Available as eBooks from iTunes and Kindle/Amazon:
Diabetes Counter – the most up-to-date information on managing diabetes
Calorie Counter – a weight loss guide that won’t let you down
Protein Counter – put the latest protein recommendations to work for you
Healthy Wholefoods Counter – planet-friendly eating made easy
Complete Food Counter – food counts and nutrition information at your fingertips
Fat and Cholesterol Counter – newest approach to heart-healthy eating
Available in print from Gallery Books:
Most Complete Food Counter, 3rd Ed.
Your Complete Food Counter App: http://itunes.apple.com/us/app/your-complete-food-counter/id444558777?mt=8
For more information on Jo-Ann and her books, go to: www.TheNutritionExperts.com.