Archive for April, 2010

Vitamin D – Maintains Health & Athletic Performance . . .

Fitness, performance, Recovery - Repair | Posted by admin April 16th, 2010

Vitamin D is an often overlooked nutritional element in athletic achievement, a sleeper nutrient, says John Anderson, a professor emeritus of nutrition at the University of North Carolina regarding Vitamin D and athletic performance. Vitamin D once was thought to be primarily involved in bone development. But a growing body of research suggests that it’s vital in multiple different bodily functions, including allowing body cells to utilize calcium (which is essential for cell metabolism), muscle fibers to develop and grow normally, and the immune system to function properly. Almost every cell in the body has receptors for Vitamin D, Anderson says.  It can up-regulate and down-regulate hundreds, maybe even thousands of genes.   D. Enette Larson-Meyer, an assistant professor in the Department of Family and Consumer Sciences at the University of Wyoming says we’re only at the start of understanding how important it is.

But many of us, it seems, no matter how active and scrupulous we are about health, don’t get enough Vitamin D. Nowadays, many people aren’t going outside very much and most of us assiduously apply sunscreen and take other precautions when we do.

Meanwhile, dietary sources of Vitamin D are meager. Cod-liver oil provides a whopping dose. But a glass of fortified milk provides a fraction of what scientists now think we need per day. A study published online in the journal Pediatrics in 2009 concluded that more than 60 percent of American children, or almost 51 million kids, have insufficient levels of Vitamin D and another 9 percent, or 7.6 million children, are clinically deficient, a serious condition. Cases of childhood rickets, a bone disease caused by lack of Vitamin D, have been rising in the U.S. in recent years.

Although few studies have looked closely at the issue of Vitamin D and athletic performance, those that have are suggestive. A series of strange but evocative studies undertaken decades ago in Russia and Germany, for instance, hint that the Eastern Bloc nations may have depended in part on sunlamps and Vitamin D to produce their preternaturally well-muscled and world-beating athletes. In one of the studies, four Russian sprinters were doused with artificial, ultraviolet light. Another group wasn’t. Both trained identically for the 100-meter dash. The control group lowered their sprint times by 1.7 percent. The radiated runners, by comparison, improved by an impressive 7.4 percent.

More recently, when researchers tested the vertical jumping ability of a small group of adolescent athletes, Larson-Meyer says, they found that those who had the lowest levels of Vitamin D tended not to jump as high, intimating that too little of the nutrient may impair muscle power. Low levels might also contribute to sports injuries, in part because Vitamin D is so important for bone and muscle health. In a Creighton University study of female naval recruits, stress fractures were reduced significantly after the women started taking supplements of Vitamin D and calcium.

Recent studies have shown that, among athletes who train outside year-round, maximal oxygen intake tends to be highest in late summer. The athletes, in other words, are fittest in August, when ultraviolet radiation from the sun is near its zenith. They often then experience an abrupt drop in maximal oxygen intake, beginning as early as September, even though they continue to train just as hard. This decline coincides with the autumnal lengthening of the angle of sunlight. Less ultraviolet radiation reaches the earth and, apparently, sports performance suffers.

Can Vitamin D Improve Athletic Performance?

The active form of vitamin D is a steroid (actually a secosteroid) in the same way that testosterone is a steroid. It is also a hormone (hormone: Greek, meaning: to set in motion) in the same way that growth hormone is a hormone. Steroid hormones are substances made from cholesterol that circulate in the body and work at distant sites by setting in motion genetic protein transcription. That is, both vitamin D and testosterone set in motion your genome, the stuff of life. While testosterone is a sex steroid hormone, vitamin D is a pleomorphic steroid hormone.

If you are vitamin D deficient, the medical literature indicates that the right amount of vitamin D will make you faster, stronger, improve your balance and timing, etc. How much it will improve your athletic ability depends on how deficient you are to begin with. How good an athlete you will be depends on your innate ability, training, and dedication?

However, peak athletic performance also depends upon the neuromuscular cells in your body and brain having unfettered access to the steroid hormone, activated vitamin D. How much activated vitamin D is available to your brain, muscle, and nerves depends on the amount of 25-hydroxyvitamin D in your residual stores. In turn, how much 25-hydroxyvitamin D is in your residual stores depends on how much vitamin D you put in your mouth or how often you expose your skin to UVB light?

References: 

The New York Times, Health – Fitness & Nutrition, 09/23/2009
Vitamin D Council: http://www.vitamindcouncil.org

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