Improved
6112 HealthChanged
3786 LivesSaved
3568 Lives0 lives impacted in the last 24 hrs Learn More
I think most of us wash our hands about the same amount in summer and winter. But we're much more likely to get sick in the winter, especially from colds and flu. So all that hand sanitizer and all the advice to “Wash your hands, wash your hands, wash your hands” does not appear to be the whole story.
What's different in summer? Well, one obvious factor is more exposure to sunlight. And all that advice about “sunscreen, sunscreen, sunscreen” is not the whole story either. Sunlight converts cholesterol into Vitamin D. Northern Europeans evolved skin with very little pigment because in the days before dietary supplements, they needed all the sunlight they could absorb. Dr. Sharon Moalem points out in his best-selling book that the Innuit people of the subarctic have relatively dark skin even though they get minimal sunlight, but their diet contains large quantities of fatty fish, rich in Vitamin D. Europeans without this dietary advantage had to lose their pigment to survive.
Dr. Moalem also notes that northern Europeans, with little sunlight, and sub-Saharan Africans, with dark skin, are both at increased risk for high cholesterol. He concludes that people at risk for Vitamin D deficiency evolved high cholesterol levels to increase the production of the vitamin from sun exposure.
Vitamin D is traditionally known for its effects on bone growth. But over the last 25 years, the role of this vitamin in the immune system has come into focus. The innate immune response is our first line of defense against infection, and is particularly important in fighting germs that mutate quickly, such as the viruses that cause colds and flu. Vitamin D boosts the production of antimicrobial peptides in this response.
The adaptive immune response is a slower but more powerful process. When something goes wrong, this is the source of autoimmune disease. Vitamin D plays a role in regulating adaptive immunity. Vitamin D deficiency is associated with type 1 diabetes mellitus, multiple sclerosis, Crohn's disease, and asthma.
Vitamin D is available as a dietary supplement, but the sunlight-generated version has an additional advantage: according to Dr. Moalem, sunlight can lower our cholesterol by converting it to Vitamin D. It's the UVB rays that do the job. Too much can cause skin cancer and folic acid deficiency, but this does not mean the optimum UVB is zero. So I'm personally taking another look at tanning booths for the dark winter months.
References:
Dr. Sharon Moalem, “Survival of the Sickest”, Harper, 2007.
Bikle D, “Nonclassic actions of Vitamin D”, J Clin Endocrinol Metab. 2009 Jan; 94(1): 26-34.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.
Add a Comment3 Comments
Vitamin D3:
NOW Vitamin D softgels supply this key vitamin in a highly-absorbable liquid softgel form. Vitamin D is normally obtained from the diet or produced by the skin from the ultraviolet energy of the sun. However, it is not abundant in food. As more people avoid sun exposure, Vitamin D supplementation becomes even more necessary to ensure that your body receives an adequate supply. Vitamin D3 on discount at NutroVita.com.
For more details please visit:
July 28, 2010 - 11:09pmhttp://www.nutrovita.com/32760/now-foods/vitamin-d-3-2-000-iu.htm
This Comment
There are new hand sanitizers that kill 3 times the germs, work up to 30 minutes, and they are safer for kids than the ones that contain alcohol. This one is my favorite: http://www.cleanphirst.com/store/alcohol_free_foam_hand_sanitizer.asp
January 27, 2010 - 10:01amThis Comment
I've had Crohn's for 30 years. I always experience a massive increase in quality of life when there is bright sunshine.
I had a bad flare-up about 5 years back, in the middle of winter. I started sunbeds (only 3 times a week, for 3 minutes each time) and experienced a marked improvement. I've been following that sunbed regime every winter since then. Although I prefer to get the real thing, and try to take a week's sun-holiday in winter, if I can.
Thanks for the article, more people should know about vitamin d3.
January 27, 2010 - 3:00amThis Comment