Protein drinks may not do your body good, our tests find

Jun 14, 2010 11:43 AM

Protein drinks now are attracting not just athletes and body builders, but also baby boomers, pregnant women, and teens looking for a shortcut to a buff body. 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 among those ages 12 to 18.

However, our recent investigation—including tests at an outside laboratory of 15 protein drinks, a review of government documents, and interviews with health and fitness experts—found that adding extra protein via these products is unnecessary for most people, and some of the drinks can even pose health risks, including exposure to potentially harmful heavy metals, if they are consumed frequently.

All of the drinks in our tests had at least one sample containing one or more of these contaminants: arsenic, cadmium, lead and mercury. For most drinks we tested, levels of those contaminants were in the low to moderate range when we could detect them at all. But with three of the products we tested, consumers who have three servings daily could be exposed to levels that exceed the maximum limits for one or two of those contaminants proposed by U.S. Pharmacopeia, a federally recognized authority that sets voluntary standards to cover dietary supplements. Nutritionists and trainers say they commonly see people who consume three servings a day, and directions for a few of the products we tested could encourage users to drink up to twice that amount daily.

Excessive protein intake over the long term can lead to further complications for diabetics or others with kidney problems. What’s more, some products had labels warning that they aren’t suitable for people under age 18 or that pregnant women should first consult a physician. And there is greater concern for these groups when it comes to exposure to heavy metals—cadmium accumulates in and can damage the kidneys, the same organs that can be damaged by excessive protein intake. Federal regulations do not generally require that protein drinks and other dietary supplements be tested before they are sold to ensure that they’re safe, effective, and free of contaminants, as the rules require for prescription drugs.

Meeting your protein requirements through a balanced diet is generally best for both your health and your wallet. You can roughly calculate how many grams of protein you need daily by multiplying your body weight by 0.4. If you’re an athlete, the general rule of thumb is about 1 gram of protein per pound of body weight per day. A sandwich with 3 ounces of chicken and an 8-ounce glass of whole milk provides about 40 grams of protein, which is more than half the 72 grams required by the average 180-pound person and nearly all of the 48 grams required by someone weighing 120 pounds.

Some foods also can be a significant source of exposure to heavy metals. For instance, shellfish and liver can be high in cadmium, and plant foods such as sunflower seeds, rice, and spinach can take in significant amounts of the metal from the environment, due in large part to the use of cadmium-containing phosphate fertilizers, according to a researcher at the federal Agency for Toxic Substances and Disease Registry. View this U.S. Food and Drug Administration list* for a sense of the concentration of metals in different foods. The Department of Agriculture* provides protein content for a wide range of foods. Choices such as milk, yogurt, eggs, poultry, and red meats are generally good protein sources that seem to contain little or no cadmium, lead, arsenic, or mercury.

—Andrea Rock, senior editor

Take a look at the extra ingredients that could be lurking in your protein drink, and read more about our tests and what the government is doing to address supplement safety on the Safety blog.

*links to PDF