The popularity of protein – and the idea that people aren't eating enough of it – has taken off in recent years.
Research shows that getting enough protein helps build muscle, reduce hunger and cravings, strengthen the immune system, increase metabolism and sustain weight loss. Social media influencers have been promoting protein powders as a convenient way to boost protein intake.
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But a new Consumer Reports analysis suggests that many popular protein powders contain high lead levels, and that the dangers of using them probably outweigh any benefit.
"We advise against daily use for most protein powders, since many have high levels of heavy metals and none are necessary to hit your protein goals," Tunde Akinleye, the food safety researcher who led the investigation, told Consumer Reports.
Lead exposure is particularly dangerous to pregnant women and children. It can lead to developmental delays, learning difficulties, lower birth weight and a host of other medical and health problems in children, infants and newborns. Repeated lead exposure at high levels also can put adults at higher risk for mood disorders, high blood pressure and other issues, the Mayo Clinic says.
Out of 23 protein powders and shakes Consumer Reports tested, more than two-thirds had dangerous lead levels in just a single serving. Consumer Reports quantifies a dangerous level of lead as 0.5 micrograms or more a day.
Two of the protein powders tested had between 1,200% and 1,600% of that lead level in a daily serving, and two other products between 400% and 600%.
Protein powders and shakes fall into the category of supplements, which the U.S. Food and Drug Administration does not have a role in approving before they come to market.
People who have been using the powders and shakes the researchers tested should not panic; occasional use of the products is probably OK, the report says.
But people should weigh the risks against the benefits – especially since most people don't really need to supplement their protein intake, the report says. Consumer Reports' findings on specific protein powders and shakes can be found in the report.
How much protein do people really need?
The "vast majority" of people in the United States get sufficient protein from food, Colleen Tewksbury, an assistant professor of nutrition science at the University of Pennsylvania, told The New York Times late last year.
Federal dietary guidelines recommend that adult women get 46 grams per day; men should get 56 grams.
The Mayo Clinic recommends the average sedentary adult get 0.8 grams of protein for every kilogram of body weight, with protein intake increasing with age. People who exercise regularly may need more protein.
The New York Times offers this protein calculator to help people pinpoint their specific protein targets.