Vitamin D deficiency is associated with obesity among children and adults. It's not clear whether the deficiency is part of the cause of obesity or a result of it. Studies have found, for example, that children who don't get enough vitamin D have more abdominal fat, gain weight faster and have higher body mass index when compared with children with adequate vitamin D. Obese adults tend to have low levels of vitamin D, too. Although there are many factors contributing to growing rates of obesity in the United States, the main culprit behind obesity is eating more calories than your body uses. Vitamin D, along with calcium, has been studied as part of a treatment plan for obesity, but see your doctor to plan the most appropriate weight-control regimen for you.
Vitamin D and Its Role in Weight Control
Vitamin D comes in two major forms, ergocalciferol, known as vitamin D-2, and cholecalciferol, or vitamin D-3. Plants make D-2, and you get D-3 when your skin is exposed to ultraviolet-B sun rays. Vitamin D can be manufactured and added to foods. Fatty fish like salmon and tuna, and fish oil, have some vitamin D. The major role of vitamin D is to maintain your levels of calcium and phosphorus, and it also provides protection against osteoporosis and high blood pressure. Its work with calcium absorption and metabolism plays a significant role in your body weight and fat. Having high levels of calcium helps to burn fat and prevent weight gain. When you have a vitamin D deficiency, you lose this protection against body fat and weight gain.
Vitamin D Deficiency and Obesity
Research, such as that reported in the September 2000 "American Journal of Clinical Nutrition," says vitamin D deficiency can be caused when the vitamin circulating through your blood is taken up by fat tissue. That means less of it is available to do its work with calcium metabolism, putting you at greater risk of weight gain. In the study, obese participants had 57 percent less vitamin D than their healthy weight counterparts. In the December 2010 issue of the journal, researchers reported that children's body mass index, waist circumference and skin-fold measurements grew faster over time when they were deficient in vitamin D. These and other studies conclude that BMI is inversely related to how much vitamin D you have coursing through you veins. That is, the lower your vitamin D, the higher your BMI and the more risk you have for obesity.
Winter Response
Because your body has several systems designed to achieve a balance of energy in and energy out, one researcher in the March 2009 "Medical Hypotheses" suggests that obesity happens as a survival adaptation that raises your so-called set point and allows for the accumulation of fat. In the past, this was an advantage. During long winters and food shortages, people got bigger, storing more energy in the form of fat mass and experienced increases in their heat-producing ability. In more modern terms, your body might react with this strange "winter metabolism" whenever you experience a shortage in vitamin D, for example, if you go outside less and get less sunlight. Researchers writing in the January 2008 "Obesity" say that the sedentary lifestyles of obese people could be related to fewer outdoor activities and reduced sunlight exposure, which may lead to a compromised vitamin D status. The "Medical Hypotheses" researcher says vitamin D deficiency can explain much of the prevalence of common obesity and that obesity rates might be reduced by improving people's vitamin D status.
Get More Vitamin D
In December 2010, public health authorities from the Institute of Medicine updated the amount of vitamin D you should get each day. From birth until about age 50, you need 5mcg daily, and then 10 to 15mcg thereafter. That's roughly 200 to 400 IU. If you get the right exposure to sunlight for about 20 minutes each day, you'd generate approximately 20,000 IU of vitamin D, according to the International and American Associations of Clinical Nutritionists.
References
- American Journal of Clinical Nutrition: Vitamin D Deficiency and Anthropometric Indicators of Adiposity in School-Age Children: A Prospective Study
- British Journal of Nutrition: Calcium Plus Vitamin D Supplementation and Fat Mass Loss in Female Very Low Calcium Consumers: Potential Link With a Calcium-Specifc Appetite Control
- American Journal of Clinical Nutrition: Decreased Bioavailability of Vitamin D in Obesity
- Obesity: Vitamin D Status and Response to Vitamin D3 in Obese vs. Non-obese African American Children
- Medical Hypotheses: Vitamin D Deficiency is the Cause of Common Obesity
- ournal of Applied Nutrition: Cholecalciferol
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