If you are a regular weightlifter, you probably know someone who uses sports supplements - you even might have tried them yourself.
It is not just professional athletes anymore who modify their diet with supplements that many say enhance athletic performance and muscle growth.
The sports supplements industry has exploded in response to an increasingly health-conscious public, selling $1 billion worth of products annually in the United States alone.
The Food and Drug Administration does not regulate sports supplements - meaning the claims of many sport supplement companies could be unverified.
This month, the controversy surrounding U.S. Olympic bobsled team member Pavle Stojanovic rekindled interest in the safety, purity and efficiency of such products.
The International Olympic Committee barred Stojanovic from participating in the Salt Lake City games after he tested positive for trace amounts of nandrolone, a muscle-enhancing steroid.
Stojanovic claims he never intended to take the steroid, saying he was especially careful not to take any banned substances.
But separate studies by the IOC and UCLA researchers have found that sports supplements often contain undisclosed substances.
"The problem with supplements is that since there's no regulation, they could be contaminated with any sort of elements that are not on the label," University Exercise Physiology Prof. Glenn Gaesser said.
Among the most popular supplements are energy generating ones like creatine, muscle enhancers like glutamine and hormonal precursors that the body converts into testosterone.
But "the only legal one that seems to be effective is creatine," said Arthur Weltman, director of the University's exercise physiology program.
Many experts have shown that creatine produces a dramatic increase in muscle mass.
Although scientists do not understand the exact mechanisms of its effects, creatine is thought to provide an extra energy source for skeletal muscle. Creatine also might increase the release of growth hormone.
"As of right now there haven't been any reports of any serious side effects" of creatine, Weltman said.
But Weltman also said his research group is studying possible ill effects of the substance on kidney function.
Another popular supplement is glutamine, which is the most abundant free amino acid in skeletal muscle. Amino acids are the building blocks of proteins, which comprise the bulk of muscle tissue.
Based on a number of animal and human studies, some researchers have suggested that glutamine effectively increases muscle mass. Much less is known, however, about the side effects of glutamine relative to creatine.
"There is some danger with taking individual amino acids," which might negatively affect metabolism, Gaesser said.
Prohormones, or testosterone precursors, probably are the most controversial group of sports supplements.
The media widely publicized prohormones after pro baseball player Mark McGuire admitted he used an over-the-counter testosterone precursor that the body produces naturally.
But "most of the testosterone precursors have been shown to have very modest effects," Gaesser said.
Synthetically made testosterone, on the other hand, long has been shown to have a potent effect on fat-free muscle build-up and remains an illegal substance.
Another potential side effect of prohormones is that they might metabolize into estrogen. According to Gaesser, prohormones also could shorten life expectancy.
This "may explain in part why the average NFL football player has a life expectancy of about 55 years, which is about 20 years less than that of the average male," Gaesser said.
No matter how much you spend on supplements, however, you can't get any results without setting foot inside the gym.
"Of things that have been known to produce muscle growth, far and away, the most important would be actually lifting weights," Gaesser said.
Read More
Student Council votes to relocate Hereford orchard and basketball hoop
By Lauren Seeliger | 7 hours agoStudent Council passed a resolution Tuesday to relocate the orchard and basketball hoop of Hereford Residential College due to construction in the surrounding area.
Dean Rucker honored with Z Society’s highest honor, Pale Z Award
By Brendon Bordwine | YesterdayThe Society has a storied history of honoring University leaders with the Pale Z.
Students receive free STI testing through U.Va. Health and Wellness
By Jackie Bond | YesterdayThrough funding from Student Council, students are now able to receive free STI testing with SHW which includes tests for HIV, Syphilis, Gonorrhea, Chlamydia and Hepatitis C.
