Heavy Metal Pollution of Protein Powders

Concerns have recently been raised about the presence of heavy metals in protein powder supplements following a Consumer Reports analysis of 15 protein powder products.

The objective of this analysis was to determine whether the heavy metal concentrations reported in protein powder supplements posed any human health risks, based on the reported concentrations of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in the protein powder.

Highlights

Protein powder supplements may contain detectable levels of heavy metals.

• A Consumer Reports study found that the average amounts of heavy metals in three servings of protein powder per day exceeded the maximum limits in dietary supplements proposed by U.S. Pharmacopeia.
• In 2010, the US Consumer Reports measured heavy metal concentrations in 15 commercially available protein powder supplements, and reported that all of the examined products contained “detectable concentrations” of at least one heavy metal.
• In a separate evaluation in 2018, the Clean Label Project tested 133 protein powder supplements, and found that all of the tested products similarly contained “detectable concentrations” of heavy metals
• Specifically, the Clean Label Project reported that 70 % and 74 % of the test products contained “measurable levels” of Pb and Cd, respectively.
• Plant-based protein powder supplements tend to have a higher heavy metal burden than animal-based protein powder supplements.
• The current study concluded that exposure to heavy metals (arsenic [As], cadmium [Cd], mercury [Hg], and lead [Pb] from protein powder supplement ingestion does not increase the non-carcinogenic risk to consumers.
• The exposure concentrations of the studied metals do not pose an increased health risk (Hazard Index < 1).
• Further, no carcinogenic risk was expected from As via ingestion of protein powder supplements. Inorganic As is the only metal in the current study for which an oral cancer slope factor, and therefore, a carcinogenic risk could be estimated.
• The protein powder HI was mainly driven by the As or Cd content in each product. The highest HI levels (which approached 1) were found in ‘mass gain’ type protein powder supplements, whereas the lowest calculated HI levels were in whey protein powders.
• It was noted that the weight-gainer protein powder supplements contained plant-derived protein sources in addition to whey protein.

Background

Heavy metals, including As, Cd, Pb, and Hg, are ubiquitous in the environment, and contamination of food can occur through a variety of anthropogenic and non-anthropogenic sources, including fresh water rivers and lakes, seafood, meats, poultry, dairy products, and cereal.

Natural factors that influence As, Cd, Hg, and Pb levels in food are the specific food type, growing conditions (soil type and water), agricultural and cultivation practices, and meteorological conditions (i.e., rate of atmospheric deposition, areas with geological formations rich heavy in metals).

Plant- and milk-based ingredients, specifically protein powder supplements, may be the primary sources of heavy metal contamination.

Plants readily uptake heavy metals through the air, water, and soil, and these heavy metals may remain in the end product even after processing.

Furthermore, milk whey (the main ingredient in whey protein powder supplements and one of the main ingredients in weight gainer protein powder supplements) is a byproduct of cheese production. Although a direct link has not been established, it is likely that contaminated milk is one of the primary contributors to heavy metal-contaminated whey protein.

The hazard index (HI) for protein powder supplements is driven by the As and Cd concentrations in the products.

The HI for weight gainers was significantly higher than whey protein powder supplements. Specifically, we noted that the weight gainer-type protein powder supplements contained a higher As content.

As and Cd contaminate foodstuffs, and these two heavy metals are commonly detected in various plant, plant-derived, and dairy products. Therefore, plant-based protein powder supplements, or protein powder supplements that are intended for vegan consumers, may contain a higher As and Cd content.

Of note, according to the Clean Label Project, products that relied on a plant-based protein tested “worst” for heavy metal content [1]. Further, the study reported that the sampled “organic” protein powder supplements contained “over 2X the heavy metals” content found in sampled “non-organic” protein powder supplements.

When ingested in sufficient quantities, As, Cd, Hg, and Pb have been associated with adverse human health effects, potentially including carcinogenesis, neurotoxicity, nephrotoxicity, and reproductive issues.

For example, chronic exposure to Cd is associated with renal disease, thyroid disruption, and weakened bones, while chronic exposure to As is associated with dermal lesions and carcinogenic effects.

Additionally, high doses of ingested Pb compete with calcium in the body, affecting neurotransmitter release and heme synthesis, which may result in nervous, hematological, reproductive, and renal effects.

Further, sufficient Hg exposure can elicit neurological, motor, renal, cardiovascular, immune, and reproductive dysfunction.

Optimal Takeaways

• Heavy metals, including arsenic, cadmium, lead, and mercury, contaminate water and food, e.g., from industrial activity.
• Protein powders should be used in moderation, preferably limited to one 30-gram serving per day.
• A Consumer Reports study found that the average amounts of heavy metals in three servings of protein powder per day exceeded the maximum limits in dietary supplements proposed by U.S. Pharmacopeia.
• Plant-based protein powders have a higher heavy metal burden than animal-based ones.

Reference

Bandara, Suren B et al. “A human health risk assessment of heavy metal ingestion among consumers of protein powder supplements.” Toxicology reports vol. 7 1255-1262. 21 Aug. 2020, doi:10.1016/j.toxrep.2020.08.001 This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).