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Adding protein powder to a postrun smoothie is a simple way to boost your intake of this important macronutrient. After all, protein is essential for repairing and building muscle, improving bone strength, and it plays a role in numerous body functions. And many runners struggle to consume enough protein to support their needs, which makes the various guises of protein powders a convenient way to get enough of it.
Protein powders are powdered forms of protein that come from plants (soybeans, peanuts, peas, rice, etc.), eggs, or milk (casein or whey protein). The amount of protein per scoop typically ranges from 15 to 25 grams. And there are many different brands of protein powders out there—now more than ever. The market for protein supplements in the U.S. has reached more than $2 billion, and experts expect this number to keep growing as more people take an interest in higher protein eating.
While using these powders is a good way to up your intake of protein, there might be a hidden risk when you whirl them into a shake or stir some into your morning oats. That’s because they can be compromised by various contaminants. This has led to headlines like “poisonous powders” and “dirty protein,” which may have left users of these supplements wondering if they should give them up to preserve their health.
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Here’s what you need to know about contaminants like heavy metals in protein powders, and if you should reconsider using one of the most popular supplements among athletes.
What the Research on Heavy Metals in Protein Powders Has Uncovered
Concerns started swirling about the presence of heavy metals in protein powder supplements following a 2010 Consumer Reports analysis of 15 protein drink products (ready-to-drink liquids or powders). The Consumer Reports study found that heavy metal exposure, when consuming three or more servings daily of these products, could pose a health risk over time. All of the protein drinks tested by the organization had at least one sample containing one or more of the following contaminants: arsenic, cadmium, lead, and mercury. For most of the drinks tested, levels of contaminants detected were in the low to moderate range.
In a 2018 follow-up, an organization called the Clean Label Project released a widely publicized report about toxins in protein powders. Researchers screened 134 products for 130 types of contaminants and found that many protein powders contained heavy metals (lead, arsenic, cadmium, and mercury), bisphenol-A (BPA), pesticides, or other contaminants—most of which have been linked to certain health conditions, including cancer.
One report on the toxicity of heavy metals says they may lower energy levels and affect functioning of organs, like the heart, brain, and liver, though this is when consumed at high levels. One study also found an association between higher BPA exposure and heart disease risk. (It’s important to note that in trace amounts, heavy metals are required for good health. In larger amounts, however, they’re toxic to humans.)
While you might not open your container of protein powder to discover Iron Maiden, some contaminants were present in significant quantities. For example, one protein powder had 25 times the allowed limit of BPA (also, 55 percent of all products tested contained some amount of BPA). The investigators detected 70 percent of protein powders had lead in them and 74 percent had detectable levels of cadmium, another heavy metal. The contaminant levels were measured based on recommended single serving sizes for each of the products (i.e. “one scoop”).
Why would a protein powder contain contaminants? They can originate from manufacturing processes or the existence of compounds in soil. For example, when something like arsenic is present in soil, it can be absorbed in the plant being grown in this soil which is then concentrated in the protein powder made from said plant.
Indeed, The Clean Label Project report suggests that plant-based (vegan) protein powders, such as soy and hemp, are the worst for containing heavy metals, with 75 percent of plant-based protein powders testing positive for lead.
Of the whey-based products tested, 10 percent had detectable levels of lead with none of the egg-based powders testing for levels of this contaminant. Whey and egg proteins may have lower levels of heavy metals because the source of the contamination would likely be the feed given to the animals. The digestive systems of the animals may diffuse some of the toxins.
For something, like BPA, it’s possible that the compound can leach into the powder from the container it’s stored in.
Worth noting is that buying a product with an “organic” label did not reduce the chances of getting a contaminated product. Certified organic protein powder products had an average of two times more heavy metals compared to the non-organic products tested. Organic fertilizers, including biosolids, have been found to contain heavy metals, which is why plant products (including protein powders) can contain them. Organic powders, however, had 40 percent less BPA than non-organic samples. The reason for this discrepancy was not determined.
Treated as a dietary supplement, the Food and Drug Administration (FDA) leaves it up to manufacturers to evaluate the safety and labeling of protein powders. While a third-party tester, like NSF, can help you ensure you’re getting better products, in many cases, it’s still difficult to know if your powder of choice is at risk.
What to Know Before You Buy Protein Powder
So does this mean you should ditch your protein powder for good? Not exactly. Keep these points in mind:
We don’t know if there are any health effects.
Arsenic, mercury, lead, and cadmium are all naturally occurring in the environment and merely detecting a compound in a food doesn’t mean it’s present in an unsafe level or that there is a problem. It means the testing instruments are sensitive enough to detect contaminants at a certain level, which might be quite low. In many cases, levels detected in powders are below federal safety guidelines.
However, contaminants like heavy metals can build up in our cells in a process called bioaccumulation causing problems to our nervous system, brain and heart, amongst other things. But we don’t have enough data to show that the amount of exposure that comes with typical protein powder usage over time is problematic. (The levels are not so high that they cause acute health effects, but only potentially problematic in the long term.)
A study in the journal Toxicology Reports, which based their conclusions on levels of heavy metals previously reported in protein powders, found that you are not likely to experience health problems from contaminant exposure if you consume protein powders in reasonable amounts. For what it’s worth, among various powders, whey protein posed the least risk, according to the investigation.
We also need to consider if the benefits of obtaining enough protein in your diet outweigh the risks of the contaminants you are getting in these powders. And we don’t know the answer to that yet.
Research is limited and potentially misleading.
To date, there have not been any studies on contaminant levels in protein powders published in peer-reviewed scientific publications. This is an important limitation, as it doesn’t allow us to grasp of the extent of the problem. It’s worth noting that the Clean Label Project is a for-profit organization and protein powder brands can pay to be certified by them to show they are below a certain benchmark for contaminant levels.
There is also some pushback from the protein powder industry, as manufacturers say the data was presented in a way to make levels of trace contaminants in powders (“detectable levels”) look especially troubling (their infographic is quite alarming, especially related to plant powders) and that funding for the group is opaque, so it’s not clear who stands to benefit from the findings.
Levels are always going to vary.
How many contaminants like heavy metals end up in a protein powder will depend on many factors, including the geographic region where the plant is grown and local soil acidity. Amounts in one batch of a protein powder could be quite different than in another batch. And there are hundreds of powders now on the market so a blanket statement about contaminant levels in these products is never going to be possible.
Not everyone faces the same risk.
Developing children are at a much greater risk of experiencing health hazards from toxins, such as lead and cadmium. Pregnant women should also be diligent to reduce exposure. Healthy adult athletes likely have more leeway concerning the consumption of these contaminants before their health takes a hit.
Protein powders aren’t the only source.
You need to know if you eat a varied diet you are almost certainly getting contaminants from other sources, as well. Rice can contain arsenic, spinach may have cadmium, and a variety of seafood will possess some mercury. Cocoa is also frequently a source of lead. Your favorite canned craft beer could give you a dose of BPA. (This chemical is still used in the lining of some canned drinks and foods.) That’s not to scare you, it’s just to say that if you simply avoid protein powders, there’s no guarantee you’ll be in the clear for contaminant exposure. Or that because there may be detectable amounts of heavy metals in these foods they aren’t safe or healthy to consume.
The Take-Home Message on Protein Powders
The reality is that it would be very difficult to create a production system where protein powders contained absolutely no trace of any potentially dangerous heavy metals and other contaminants. But it’s too premature to make a blanket statement that using them can lead to health risks or that you should skip them altogether. However, there are a few steps you can take to mitigate the risk:
- The risk of going overboard on contaminants likely increases as daily servings of protein powders go up. Consider limiting servings to two a day. You should still prioritize getting most of your protein from whole foods.
- If you’re not a solely plant-based eater consider using milk-based protein powders, such as whey, as these seem to carry a lower contaminant risk. Or use one serving of animal-based and one serving of plant-based protein during the day as a way to potentially lower exposure.
- Look for brands that regularly batch-test their products for contaminants using an independent third party. You should be able to find this information on the brand website. For some consumers, this transparency is important and allows you to make an educated choice regarding the products you choose. Remember, finding products with zero contaminant levels is not likely, but third-party testers can help you feel better about what’s in your product.
- Chocolate-flavored protein powder may have higher heavy metal counts than other flavors like vanilla because of the use of cocoa powder, which has been shown to contain varying levels of contaminants, including lead. So choose your flavors wisely.
