Consumer’s Reports published a report on health risks associated with protein powders, including a discussion of the risks associated with heavy metal contaminants found in some brands of powders. I’ve commented previously on the shortcomings in their reporting of the risks from the heavy metal contaminants, which I predict will do more to alarm and confuse people than inform them.
However, far be it for me to simply criticize CR’s work without making the attempt to try and communicate health risk issues with heavy metals in protein powders more clearly. So, I’ll take a run at talking about cadmium, because I kind of ran arsenic into the ground with the last post (Note that an expanded version of this post, providing a more detailed discussion of cadmium risks from protein powders, can be found here).
Cadmium is naturally occurring in soil and water, and can accumulate into the food chain. For nonsmokers, dietary exposure to cadmium is the most likely route of exposure, with nuts, grains and vegetables providing the largest contributions to dietary exposure. The toxic effects of cadmium on humans have been extensively studied, and evidence in humans indicates that the kidneys and bones are important target organs for cadmium toxicity. Scientific studies of adverse effects to the kidney have been used by government agencies to estimate the limits on cadmium ingestion that do not have an appreciable risk of adverse effects; these limits are based on the most sensitive indication of adverse kidney effects, and include a margin of safety. Authorities responsible for assessing the safety of dietary supplements, such as the U.S. Pharmacopeia (USP) use these very same limits. The article in CR uses these USP limits to draw attention to cadmium levels in protein powders and drinks.
But is your risk from cadmium really different with protein powders? In general, the amount of cadmium exposure and risk from protein powders used as meal replacements probably is not appreciably different from meals prepared from ordinary foods. This is not to say that protein powders (or foods for that matter) are free of risk. Some recent scientific papers (examples here and here) argue that the margins of safety on cadmium exposure are either very small or inadequate. However, it is arguable that one’s risk is no different with or without protein powders or drinks in the diet (some of the homework supporting this assertion is here).
The article in CR could lead you to think that in general everyone using protein powders are at risk of kidney disease from cadmium. There are people who are at increased risk of adverse effects from cadmium exposure: age, general health and nutritional status, whether one is a smoker (smoking makes a substantial contribution to cadmium exposure) and the presence of pre-existing kidney disease, are key risk factors. I tried to think of an example of someone who might be at an increased risk of cadmium-related adverse effects from using protein powders. Here’s what I came up with:
A skinny hard-gainer teen-aged kid who, in addition to consuming a lot of protein powder also eats a lot of spinach, sunflower seeds, whole-wheat bread and oatmeal. He or she would either be employed or have well-off parents in order to afford all of the protein powder being consumed. He or she also would have kidney problems related to diabetes or some other preexisting condition. Bonus points for being a smoker.
Keep all of this up through middle-age, and this individual might be at an appreciable risk of kidney toxicity or osteoporosis from cadmium exposure. The take-away point, for me at least, is that normally healthy people including protein powders and drinks in conjunction with a healthy diet (and not smoking. . .) shouldn’t appreciably be increasing exposure or risk from cadmium.
Ultimately, it’s up to you what you do to maintain and enhance your health. What people need to do that is information that explains as clearly as possible what the risks from heavy metals might be, and provide the information balancing benefits versus risks of using protein powders. The sound-bites that were supplied in the article in CR generally were pretty un-informative for users of protein powders about the relative benefits and risks.