Pushing an image of fitness

Protein drinks are helping fuel the growing sales of sports-nutrition products, which now top $2.7 billion.

Teenagers who want to look like the sculpted images they see in fitness magazines are particularly vulnerable to the marketing messages, experts say, because they are easily hooked by the promise of "hope in a can." They tend to overuse the products, assuming that if one scoop is good, four or five would be even better, says Dave Ellis, of Colorado Springs, Colo., who has 28 years' experience as a sports dietitian for college and professional athletic teams. A 2005 study published in Pediatrics, the journal of the American Academy of Pediatrics, found that protein powders and shakes were the supplements most commonly used by those aged 12 to 18.

Andrew Shao, senior vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a supplement industry group, says that protein powders and drinks are a safe option for teenagers and even pregnant women. But we found that some products had labels warning that they are not suitable for people under age 18 or that pregnant women should first consult a physician.

Kathy Burns, a toxicologist and founder of Sciencecorps, a Boston-area nonprofit network of science and medical professionals, was concerned about possible health effects of protein supplements her then high-school-aged son and his friends extensively used. She and her colleagues sent a small sampling of protein supplements to be screened at an independent lab. Burns said what they found worried them, and she contacted Consumer Reports.