It was supposed to be a routine study.
At the University of Minnesota 2 years ago, Shalamar Sibley, M.D., was examining how calorie reduction might affect hormone pathways. On a hunch, she decided to test one more variable: vitamin D. “Researchers have been tracking the relationship between low vitamin D and obesity,” says Dr. Sibley. “So I wondered if people’s baseline vitamin D levels would predict their ability to lose weight when cutting calories.”
Her hunch paid off—big time. People with adequate vitamin D levels at the start of the study tended to lose more weight than those with low levels, even though everyone reduced their calorie intake equally. In fact, even a minuscule increase in a key D precursor caused the study participants to incinerate an additional half pound of flab.
Dr. Sibley’s study is just the latest indication that vitamin D could be our special ops agent in the war against body fat. For example, a study at Laval University in Quebec City found that people who consumed more dietary vitamin D had less belly fat than people who ate less.
“Vitamin D deficiency is one of the most commonly unrecognized medical conditions,” says Michael F. Holick, M.D., Ph.D., a professor of medicine at Boston University medical center and author of The Vitamin D Solution. “And that deficiency negatively affects every cell in your body—including your fat cells.”
One reason vitamin D has flown under the research radar for so long is because it’s more than just a vitamin—it’s also a hormone, one that plays a role in a remarkable range of body processes. Studies show that D can combat high blood pressure and diabetes, too. Now add to this list of the potential to ward off memory loss, certain cancers, and even the common cold, and it should come as no surprise that D may also help solve the riddle of your expanding middle. Here’s the rundown on the many benefits of boosting your vitamin D.
1. You’ll eat less but feel more satisfied.
When you have adequate vitamin D levels, your body releases more leptin, the hormone that conveys a “we’re full, stop eating” message to your brain. Conversely, less D means less leptin and more frequent visits to the line at the Chinese buffet. In fact, an Australian study showed that people who ate a breakfast high in D and calcium (a mineral that works hand in hand with D) blunted their appetites for the next 24 hours. Vitamin D deficiency is also linked to insulin resistance, which leads to hunger and overeating, says Liz Applegate, Ph.D., director of sports nutrition at the University of California at Davis.
2. You’ll store less fat.
When your D is low, levels of parathyroid hormone (PTH) and a second hormone, calcitrol, rise, and that’s bad: High levels of these hormones turn your body into a fat miser, encouraging it to hoard fat instead of burning it, says Michael B. Zemel, Ph.D., director of the nutrition institute at the University of Tennessee.
3. You’ll burn more fat—especially belly fat.
Vitamin D can help you lose lard all over, but it’s particularly helpful for the pounds above your belt. Studies at the University of Minnesota and Laval University found that D triggers weight loss primarily in the belly. One explanation: The nutrient may work with calcium to reduce production of cortisol, a stress hormone that causes you to store belly fat, says Zemel.
4. You’ll lose weight—and help your heart.
One of Zemel’s studies found that a diet high in dairy (which means plenty of calcium and vitamin D) helped people lose 70 percent more weight than a diet with the same number of calories but without high levels of those nutrients. What’s more, a German study showed that high levels of vitamin D actually increased the benefits of weight loss, improving cardiovascular risk markers like triglycerides.
Why Not Just Step Outside?
When sunlight hits your skin, your body’s built-in vitamin D factory kicks into operation, producing a form of the nutrient that lasts twice as long in your bloodstream as when you consume it through food or a supplement. The problem, of course, is a little thing called skin cancer: In order to manufacture enough D, you’d need to be in the sun during the peak hours of 10 a.m. to 3 p.m. without sunscreen, says Dr. Holick. But even if you could take cancer out of the equation, the amount of sunlight-derived D your body can produce depends on your location. People who live north of the equator probably make only 10 to 20 percent as much D in April as they do in June. And come December, a northerner’s skin can produce hardly any D, says Dr. Holick. Even living in a sunny city is no guarantee of adequate natural D. Air pollution filters UVB rays, so less of them are able to reach your skin. That’s one reason folks who live in Los Angeles and Atlanta tend to be deficient despite their sunny locations.
Are Supplements the Answer?
Supplementing is a good idea. In fact, the Institute of Medicine recently unveiled a new D recommendation for food and/or supplements: 600 international units (IU) a day. But even that might not be enough. The Endocrine Society recently released a revised recommendation of 1,500 to 2,000 IU a day for good health.
The other problem with trying to ingest all that D from a handful of pills is that you may not reap the fat-burning benefits you were hoping for. “Dietary sources of D usually contain complementary nutrients that also contribute to weight loss,” says Dr. Holick. Bottom line: A supplement is just that.
Source: Men’s Health: http://www.menshealth.com