Millions of people in the U.S. take protein powder to boost athletic performance or manage their weight. But a new study says many forms of the supplement also come with an unhealthy dose of heavy metals.
Popular protein powders often contain high levels of lead and cadmium, according to a new report from the Clean Label Project.
In a test of 160 protein powders:
- Plant-based protein powders had three times the level of lead and five times the level of cadmium found in products based on whey.
- Organic protein powders had three times more lead and two times as much cadmium as non-organic powders.
- Protein powders flavored with chocolate had four times as much lead and a whopping 110 times more cadmium than vanilla-flavored powders.
Overall, 47% of the tested protein powders exceeded the threshold levels of lead established by California’s Proposition 65 regularly limits. More than one-fifth of powders — 21% — had levels of lead that were twice the limit established by the threshold.
It is normal for plants to absorb some heavy metals from soil and water, but the problem can grow worse when the plants are grown in tainted soil.
Why heavy metals are dangerous
The heavy metals found in protein powders theoretically could pose health risks to people who consume these supplements.
Any amount of exposure to lead is potentially dangerous to humans, according to the Centers for Disease Control and Prevention. When exposed to high levels of lead, humans face a higher risk of being diagnosed with:
- Anemia
- Kidney and brain damage
- Infertility
In a worst-case scenario, high levels of exposure to lead can result in death.
Exposure to cadmium can damage a person’s kidneys, lungs and bones. Cadmium is also a known carcinogen that can cause cancer in humans.
Heavy metals in protein powder: What the study’s results mean for you
The Clean Label Project’s report is likely to raise concerns for those who regularly use protein powders.
However, it’s important to understand the report in its full context, says Lindsay Cohen, a Missouri-based registered dietitian nutritionist and founder of Mama-Betes, a blog for moms with diabetes.
“The study found elevated levels of contaminants in some products, not all protein powders,” Cohen says.
Cohen — who was not involved with the study – also notes that other research has not found a link between exposure to heavy metals in protein powders and specific types of health risks.
For example, a 2020 study published in the journal Toxicology Reports found that exposure to heavy metals in protein powder supplements “does not pose an increased non-carcinogenic risk to human health.”
Although Cohen says the Clean Label Project’s findings are concerning and underscore the need for stricter regulation and testing within the supplement industry, she cautions against overreacting to the study’s findings.
“Based on this study alone, people should not feel the need to avoid protein powder,” Cohen says. “However, it may be best to do some research and consider the type of protein powder that you are using if it is a regular part of your diet.”
The pros and cons of using protein powders
Protein powders offer an easy and quick way to boost protein intake, Cohen says, “especially for people with specific dietary needs.” Such folks include:
- Athletes
- Vegans
- People recovering from surgery
- Those who struggle to meet their protein requirements through whole foods alone
However, protein powders can be expensive. In addition, Cohen says whole-food sources of protein offer a wider range of nutrients and can be more healthful.
“Protein powders are processed foods, and some may contain artificial sweeteners, flavors and other additives,” Cohen says.
Protein powders also may add high levels of calories to your diet. Harvard Medical School notes that some protein powders can have up to 23 grams of added sugar per scoop.
That could mean adding more than 1,200 calories to a simple glass of milk.
Buying safer protein powders
Because protein powders are dietary supplements, the U.S. Food and Drug Administration does not test their safety or evaluate their labels.
If you plan to purchase protein powder, Cohen suggests using a little extra care when you shop.
She recommends looking for brands with a good reputation for quality and transparency, and researching the company’s testing practices. Cohen notes that some companies may publish their own results after testing for heavy metals.
Also, look for products tested by organizations such as NSF International or ConsumerLab.
“These organizations verify label claims and test for contaminants,” Cohen says.
The Clean Label Project’s report lists more than a half-dozen companies that produce protein powders safe enough to earn recognition as being Clean Label Project Certified.
Discuss protein powder use with your doctor or a registered dietitian, especially if you have any health concerns, Cohen adds.
Alternatives to using protein powders
Those who are concerned about the presence of heavy metals in powders can still get their fix of protein in other ways.
Cohen says alternatives to protein powders include using whole food sources of protein, such as:
“It’s important to remember that protein powder is a supplement, not a replacement for a healthy, balanced diet,” Cohen says.
She urges folks to prioritize getting protein from whole-food sources whenever possible.
“Make sure not to rely solely on protein powder to meet your protein needs,” Cohen says.
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