Skip to comments.Losing more than 15 percent of body weight significantly boosts vitamin D levels in overweight women
Posted on 05/25/2011 2:37:08 PM PDT by decimon
Obesity and low vitamin D are linked to risk of cancer and other diseases
SEATTLE Overweight or obese women with less-than-optimal levels of vitamin D who lose more than 15 percent of their body weight experience significant increases in circulating levels of this fat-soluble nutrient, according to a new study by researchers at Fred Hutchinson Cancer Research Center.
"Since vitamin D is generally lower in persons with obesity, it is possible that low vitamin D could account, in part, for the link between obesity and diseases such as cancer, heart disease and diabetes," said Caitlin Mason, Ph.D., lead author of the paper, published online May 25 in the American Journal of Clinical Nutrition. "Determining whether weight loss helps change vitamin D status is important for understanding potential avenues for disease prevention," said Mason, a postdoctoral research fellow in the Hutchinson Center's Public Health Sciences Division.
According to the National Institutes of Health, vitamin D plays many important roles in the body. It promotes calcium absorption and is needed for bone growth and bone healing. Along with calcium, vitamin D helps protect older adults from osteoporosis. The nutrient also influences cell growth, neuromuscular and immune function, and reduces inflammation. Many gene-encoding proteins that regulate cell proliferation, differentiation, and apoptosis (programmed cell death) are modulated in part by the vitamin.
The year-long study one of the largest ever conducted to assess the effect of weight loss on vitamin D involved 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups: exercise only, diet only, exercise plus diet and no intervention.
Those who lost 5 percent to 10 percent of their body weight equivalent to approximately 10 to 20 pounds for most of the women in the study through diet and/or exercise saw a relatively small increase in blood levels of vitamin D (about 2.7 nanograms per milliliter, or ng/mL), whereas women who lost more than 15 percent of their weight experienced a nearly threefold increase in vitamin D (about 7.7 ng/mL), independent of dietary intake of the nutrient.
"We were surprised at the effect of weight loss greater than 15 percent on blood vitamin D levels," said senior author Anne McTiernan, M.D., Ph.D., director of the Hutchinson Center's Prevention Center and principal investigator of the study. "It appears that the relationship between weight loss and blood vitamin D is not linear but goes up dramatically with more weight loss. While weight loss of 5 percent to 10 percent is generally recommended to improve risk factors such as blood pressure, cholesterol and blood sugars, our findings suggest that more weight loss might be necessary to meaningfully raise blood vitamin D levels."
About 70 percent of the participants had less-than-optimal levels of vitamin D when the study began; at baseline, the mean blood level of vitamin D among the study participants was 22.5 ng/mL. In addition, 12 percent of the women were at risk of vitamin D deficiency (blood levels of less than 12 ng/mL).
The optimal circulating range of vitamin D is thought to be between 20 and 50 ng/mL, according to a recent data review conducted by the Institute of Medicine, which found that blood levels under 20 ng/mL are inadequate for bone health and levels over 50 ng/mL are associated with potential adverse effects, such as an increased risk of developing kidney stones.
Vitamin D is naturally found in some foods, such as fatty fish, and is produced within the body when skin is exposed to sunlight. According to the Institute of Medicine, just 10 minutes of sun a day is enough to trigger adequate vitamin D production. The estimated average requirement via diet or supplementation is 400 international units per day for most adults.
"It is always best to discuss supplementation with your doctor, because circulating levels can vary a lot depending on factors such as age, weight, where you live, and how much time you spend outdoors," Mason said. Vitamin D levels tend to decrease as people age and are generally lower among those with dark skin.
It is thought that obese and overweight people have lower levels of vitamin D because the nutrient is stored in fat deposits. During weight loss, it is suspected that the vitamin D that is trapped in the fat tissue is released into the blood and available for use throughout the body.
"Vitamin D is found in several different forms in the body and its pathways of action are very complex, so the degree to which vitamin D becomes available to the body as a result of weight loss is not well understood," Mason cautioned.
A possible link between vitamin D deficiency and chronic diseases, including cancer and heart disease, is also not well established. "More targeted research ongoing at the Hutchinson Center and elsewhere aims to better understand whether vitamin D plays a specific role in the prevention of these chronic diseases," McTiernan said. To that end, McTiernan is recruiting Seattle-area obese and overweight postmenopausal women for a separate new study to assess the impact of vitamin D on weight loss and breast cancer risk factors.
The National Institutes of Health, the National Cancer Institute and the Canadian Institutes of Health funded the research reported in the American Journal of Clinical Nutrition. The study also included investigators at the University of Washington, the University of Illinois at Chicago, the University of British Columbia, Case Western Reserve University, the University of Minnesota, the National Cancer Institute and Harvard Medical School.
At Fred Hutchinson Cancer Research Center, our interdisciplinary teams of world-renowned scientists and humanitarians work together to prevent, diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers, including three Nobel laureates, bring a relentless pursuit and passion for health, knowledge and hope to their work and to the world. www.fhcrc.org
Makes me wonder if the whole SPF addiction started the obesity epidemic in this country.
It certainly put toxins into the bloodstream. They are saying that for the few cancers that the Sun causes....it prevents hundreds of other cancers. How natural is it to put some toxins on the skin—esp. on skins of young children whose sensitivity is much greater to toxins.
Some of the healthiest, longest living peoples on earth are those who have few toxins in their environment and food supply—not less sunshine or stuff on their skins to prevent the natural rays of the sun from preforming their natural function. They have no “sunscreen”. You protect yourself from the sun with clothing.
Thanks for posting. I was not aware of this issue until recently when my doctor mentioned it and prescribed Vitamin D for me, although my deficiency is borderline.
There have been many vitamin D posts here. Some within the past few days.
May I ask how much vitamin D your doctor recommended?
Someone who never used sunscreen.
Lifespan always had a lot to do with the availability and quality of food and water. Sure, clean water, etc., has always been a problem, but now you have intentional additives (advertised for our good and safety and for profit) that are known to be poisonous and toxic intentionally inserted into sunscreens, vaccines, water, hair dyes, plastics, foods, medicines, cleaners, fertilizers, light bulbs, etc. The results of these are not benign and government and companies know it, but intelligent information and debate is suppressed by crony capitalism.
My point is that nature (when not contaminated) is the best. The sunshine is a good—not evil—and it is all about balance. Sunscreens have known toxins in them and it is not known the long term impact on young children who are the most vulnerable to toxins. They are guinea pigs used for profit. I intentionally and successfully avoided sunscreen on my children and we lived in the Bay Area.
The object in nature is for balance. Either extreme is destructive—not denying that.
Truly free markets have always been the answer, but if you think we have free markets today, refer back to Ayn Rands writings and commentary—and that was before the sixties. Even back in the 19th century....Free markets? In your dreams. With corruption and human nature, we can never have free markets until we are a “virtuous” nation and we are dropping into the sewer as I speak.
Legal system is so corrupt in the US there can be no free markets. It is all crony capitalism.
I think you are discounting that man is a rational creature and, as such, has had a tremendous power over nature to form and shape it in ways that other animals have no chance at doing.
Manipulation of nature (and carcinogens), within reason, has always been possible and has been done since the time of the caveman.
Well, I definitely agree with that.
I am just pointing out that greed and corruption in people and corporations will inject toxins into the environment unsuspectingly and intentionally for profit (and some for nefarious ends), and with corruption and ineptness in government agencies, there will and can be a cover up. It happens all the time.
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