Food Safety: Heavy Metals: As They Stand Today

By Tom Jonaitis of EAS Consulting

A plethora of research and headlines have been circulating regarding the presence of detected heavy metals, with a particular focus on lead, cadmium, arsenic, and mercury, in a wide range of foods.

Whether it is chocolate, baby foods, fruit pouches, dairy products, fruit and vegetables, grains, meat products or ocean-derived products (even water and beverages) it seems alarms have been sounding about the dangers of heavy metals showing up in nearly all types of foods.

Food safety is a paramount concern not only for food companies, but also regulators and consumers, and it is important that all of these stakeholders come together to understand the risks of trace levels of heavy metals in foods and put them into proper context.

Whether the product is an apple or a cracker, what does a detection of a metal mean regarding safety? This article provides a brief overview of some of the current safety considerations and data on heavy metals in foods.

For background, heavy metals are naturally occurring elements found in the Earth's crust and soil and can be taken by plants and other agricultural commodities -- ending up in our food in an unavoidable manner. However, their accumulation in foods due to man-made industrial activities, agricultural practices and environmental pollution is of greater concern and can pose increased health risks to consumers worldwide when concentrated not only in certain foods but also when contributing to the aggregate intake across the diet even at minute, trace levels.

The FDA has been monitoring and testing food products for decades to assess the risks of heavy metals in foods. In 2022, the FDA updated its interim reference levels (IRLs) for lead from food by lowering them to 2.2 micrograms/day for children and 8.8 micrograms/day for females of childbearing age. This further reduces the previously published IRLs based on the CDC’s updated blood level reference value (BLRV) of 3.5 micrograms/dL, which is associated with decreases in IQ points in children.

However, it should be noted that the FDA does imply that exposures below the IRLs are “safe,” as no amount of lead is “safe,” and this process is part the FDA’s “Closer to Zero” action plan to limit heavy metals in infant and children’s foods to the greatest extent possible in a step-wise manner.

It should be noted that there are also specific heavy metal limits (action levels) defined for various food types. Given the complexities and practicalities of currently eliminating heavy metals to “zero,” which might not even be possible, the IRLs are there to provide a benchmark for stakeholders to gauge whether a food product is significantly contributing to an individual’s overall lead intake.

Based on current dietary intake estimates, mean intakes of lead by children were just below the IRL for children, while 90th percentile intakes exceeded this limit. This indicates that although lead intake has been decreasing over time, it may still be a health risk for certain populations of children.
Cadmium exposures appear not to be decreasing and may exceed limits, particularly for infants. Other dietary intake surveys also raise concerns about certain populations and exposures to metals in foods.

The Joint World Health Organization’s Food and Agriculture Organization Expert Committee on Food Additives withdrew its original provisional tolerable weekly intake (PTWI) level in 2011, as it concluded that it could not establish a health protective value. Around the same time, the European Food Safety Authority (EFSA) also rejected the PTWI and derived a limit value of 0.5 micrograms/kg bw/day in children for neurodevelopmental effects and slightly higher limits for adults.

In contrast, under California Proposition 65, the Maximum Allowable Dose Level (MADL) for lead was originally set in 1989 at 0.5 micrograms/day (as it relates to any one product) and has been a costly thorn in the side of all industries for decades with the threat of civil litigation and/or costly settlement fees levied against them.

Every single month, dozens of food and supplement companies are targeted for alleged presence of heavy metals, particularly lead, in their products. Even when companies have done the utmost in due diligence, the threat litigation leads many to settle with fees ranging into the tens of thousands of dollars.

Interestingly, there was an attempt by a plaintiff group about a decade ago to modify the MADL, which was not considered protective enough, and update it with newer scientific evidence, including lowering it to 0.2 micrograms/day for single day exposures, plus accounting for products that are less frequently ingested (i.e., these would have a higher MADL). Despite these efforts, this proposal was not accepted and appears to be dead in the water.

Nonetheless, there are some useful aspects that have come out of Proposition 65 regulations and case law that can be useful for companies to better understand the risks associated with the detection of heavy metals in foods.

There is some element of certain foods that establishes that metals are “naturally occurring,” which is prescribed in the regulations. This is an unavoidable amount of certain metals that are present and minimized to the greatest extent possible; however, this is nearly impossible to prove definitively (differentiating between truly natural and that from man-made sources), and therefore few companies have succeeded in using this approach.

At least for rice, there are levels that are captured in the regulations for arsenic. Another aspect is averaging of exposures over time when foods are not consumed daily. This is also consistent with FDA’s approach. However, it can be difficult to establish how often a food item is actually consumed for average consumers.

Heavy metal contamination in foods remains a significant public health concern, particularly as it relates to infants and children. This necessitates ongoing joint efforts from stakeholders across the food industry and regulatory bodies. This is particularly important as it relates not only to individual food items and food companies, but the cumulative exposure across the entire diet.

Most companies in these sectors are well-aware of the safety of their products, including heavy metals, but as consumer, and other stakeholder, awareness continues to hone in on various food products, companies should remain on guard to ensure their sourcing, testing and safety analysis continues to be as robust and accurate as possible.