Heavy Metals 101
According to the FDA, environmental contaminants can be present in foods because they are in the soil, water, or air where foods are grown, raised, or processed.
Environmental contaminants include:
Arsenic, Lead, Mercury, and Cadmium, sometimes referred to as heavy metals or toxic elements, may occur naturally in the environment and are often at higher levels from past industrial uses and pollution.
You can read more about other environmental contaminants here.
The effects of heavy metal exposure often occur gradually, accumulating in the body over time, potentially causing damage that may not be immediately noticeable. Children are especially vulnerable to lead, mercury, arsenic, and cadmium as their bodies are still developing.
Heavy metals exist naturally in the environment. Deep within the Earth’s crust lie pockets of these elements. Volcanic eruptions spew them into the air, and wind can carry these tiny particles for long distances before they settle on soil or water. Even dust storms can contribute, lifting and spreading these naturally occurring heavy metals. Plants growing in this soil might absorb these metals alongside the very nutrients people need to grow and maintain their physical health. Levels of naturally occurring heavy metals in soil are often very low and unlikely to pose a health risk. However, if high levels of heavy metals are present, foods may have higher concentrations.
Not all plants are equal when it comes to absorbing heavy metals. The peels of fruits act as a barrier, limiting the amount of heavy metal that can reach the edible part. However, some fruits with thin skin or those grown in contaminated soil may still contain trace amounts. It’s also important to be aware that plants absorb heavy metals differently. For example, rice naturally absorbs more arsenic, lettuce and onions accumulate lead more readily, and spinach and carrots accumulate cadmium present in the soil more easily.
Fish are another potential source of heavy metal exposure. Larger, predatory fish like tuna, swordfish, and king mackerel can accumulate heavy metals through their diet. As smaller fish eat contaminated plants or animals, the heavy metals become more concentrated as they move up the food chain, which means large fish may contain much higher levels of heavy metals compared to the smaller fish it eats. Generally, animals raised on contaminated feed or grazing on polluted land can also contain traces of heavy metals in their meat.
Human activities can significantly increase the amount of heavy metals in the environment. Mining operations extract these metals from the Earth, but the process isn’t always clean. Dust from mining sites or improperly stored waste can release heavy metals into the air. This industrial pollution can travel long distances before settling on soil or water, contaminating areas far from the source.
Lead has entered the environment from past widespread use of lead in paint, gasoline, and plumbing materials, as well as many other products. While many commercial and industrial uses of lead have been phased out, there are still some products used or made in the U.S. that contain lead, and it is still used in some products made in other countries.
The methods used to manufacture can also play a major role in limiting the heavy metals in food. Certain types of packaging or processing equipment might leach small amounts of metals into foods with which they come into contact. In the past, heavy metals have been components of inks, labels, dyes, pigments, adhesives, stabilizers, and other packaging additives. These metals can leach into the food, especially if it’s acidic (like tomatoes) or stored for extended periods.
Economically Motivated Adulteration (EMA), when a producer intentionally leaves out, takes out, or substitutes a valuable ingredient or part of a food in order to reduce costs can result in a number of health issues including introducing allergens and the inclusion of heavy metals in food. For example, lead-based dyes can be added to give spices a certain color, especially when the color strongly impacts the perception of quality. These and other industrial dyes can cause adverse health problems and have been found in spices such as chili powder, turmeric, and cumin.
Heavy metal contamination in food is a concern, and ongoing efforts are crucial to minimize exposure and associated health risks. Manufacturers can play a significant role by scrutinizing their supply chains to limit heavy metal exposure in crops and animals. Additionally, they can explore processing methods that don’t inadvertently concentrate naturally occurring metals in food. Furthermore, collaborating with farmers and suppliers to source ingredients with lower baseline levels of heavy metals can contribute to a reduction in overall risk.
However, it’s important to understand the limitations of completely eliminating heavy metals from our food system. These elements exist naturally in the environment, absorbed and sometimes concentrated by plants and animals. While striving to minimize exposure, especially for vulnerable populations like children, complete eradication is neither practical nor necessarily desirable.
Here’s why: Aiming for zero heavy metals might lead to an unintended consequence – a drastic shift in our food choices. Imagine a scenario where readily available options consist primarily of highly processed products. These might be formulated with deionized water, added sugars and other isolated nutrients for fortification, and artificial flavors and colorings. This approach would remove whole fruits, vegetables, and whole grains from our plates, along with their wealth of known and yet-to-be-discovered health benefits.
Therefore, striking a balance is key. Rigorous testing, vigilant monitoring of producers and manufacturers, and ongoing research into reducing heavy metal contamination are crucial. By focusing on these areas, we can ensure a food system that prioritizes safety while still offering the rich diversity and nutritional value of whole foods.
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