Grains May Be a Staple, but What About Those Heavy Metals?

Originally published by A Voice For Choice Advocacy on January 23, 2025.

EDITOR’S SUMMARY: Change can be hard, especially when it comes to giving up foods you love, or rely on for satiety. And while moderation works in some cases, you will have to parse out the details to make your most informed decisions. Navigating a diet is tricky when so many toxins are present, as is the case with heavy metals seeping into crops in a variety of ways. When health symptoms arise that cannot be accounted for or put to rest, heavy metal toxicity may be an area to explore to explain cause and effect.

Written by Carter Trent

Edited by Nicki Steinberger, Ph.D.

Grains are a dominant food source in cultures around the globe. Rice, corn, and wheat make up a staggering 60% of the world's food energy intake. Rice alone is eaten by nearly half of humanity. Yet although grains play a significant role in today’s food supply, they come with a downside. They contain elements called heavy metals, which can be toxic to your health, and are in all types of crops, including wheat, barley, rice, millet, and corn. Heavy metals are naturally occurring elements found in the earth’s crust. They possess a density at least five times greater than water, which is why this class of metals are described as “heavy.” They also accumulate in soil as a result of human pollution. Sources include industrial waste due to mining and manufacturing, and leaching from trash, such as from discarded batteries.

A wide variety of minerals are grouped as heavy metals. Examples are cadmium, mercury, iron, zinc, copper, and arsenic. They enter your body when you eat grains and other foods containing them. Some heavy metals are essential nutrients in small doses. These include selenium, iron, copper, and zinc. They provide benefits, such as immune system support, antioxidants important to reducing your cancer risk, and in the case of iron, are essential for healthy blood. Nonetheless, if you consume too much of these “beneficial metals,” they can be toxic for you. For instance, while your body needs small amounts of iron, too much can create health issues, including constipation, nausea, abdominal pain, and vomiting. How much iron you need depends on several factors, such as age, gender, and whether you’re pregnant or breastfeeding.

As an example, the recommended daily allowance (RDA) of iron for an adult female over the age of 50 is 8 milligrams. You can easily get this amount from including grass-fed/finished red meat, organ meat, pastured, organic eggs, and legumes in your diet. But once you exceed 25 milligrams, the iron can start to impact your health by blocking your body’s ability to absorb zinc. And though wild seafood can also be a good source of iron, be aware that fish are also at high risk for containing heavy metals due to marine pollution. Keep in mind that these toxins can be transported over extremely long distances. In the article, “Assessment of health risks associated with heavy metal contamination in selected fish and crustacean species from Temsah Lake, Suez Canal,” it is stated:

“Marine pollution with heavy metals is a significant environmental issue that has garnered increasing attention in recent years. Heavy metals, such as cadmium, nickel, lead, mercury, and tin can accumulate in the tissues of marine organisms over time, posing a serious threat to the health of both marine ecosystems and human populations that rely on seafood as a primary source of nutrition.

Routinely ingesting too much iron results in the excess getting deposited into your organs, a condition called iron overload. This can cause the aforementioned health issues, up to and including organ failure and death. Heavy metals not needed for nutrition, such as arsenic, cadmium, and lead, are toxic at any level. To help distinguish these from the beneficial ones, the U.S. Food and Drug Administration (FDA) has taken to calling this group “toxic elements.” If you’re eating grains on a regular basis, these heavy metals can accumulate in your body over time. Some, such as lead, can take years for your body to eliminate. Not only are you getting them from eating wheat, rice, and other grains, you’re also exposed to them from products using grain as an ingredient. Examples include packaged foods such as energy bars, rice milk, cereal, and baby food. All of these contain grain, and hence, heavy metals. The impact of these toxic elements on your body varies based on many factors. This includes which heavy metals you’re exposed to, for how long, how much you consume over time, your overall health and body’s effectiveness at purging the toxins, and genetic factors, such as sensitivity to a specific metal.

Some of the health issues that can develop from heavy metal toxicity include kidney disorders, nervous system damage, immune system dysfunction, heart disease, and cancer. Chronic exposure over many years can also lead to subtle, insidious effects, such as damage to your brain, and mental health imbalances, including anxiety and depression. One study, “Low-level lead exposure and mortality in US adults: a population-based cohort study,” published in The Lancet, looked at the levels of lead in the blood of more than 14,000 adults over a 20-year period. The amount of lead in the blood required to trigger cardiovascular disease was determined to be less than 5 micrograms per deciliter, where a microgram is one-millionth of a gram, and a deciliter is one-tenth of a liter.

Based on the participants who died during the study period, the researchers estimated 400,000 deaths per year in the U.S. are due to cardiovascular issues caused by lead exposure from food. Lead can damage your brain, resulting in memory loss, and intelligence quotient (IQ) reduction. “Low-level environmental lead exposure in childhood and adult intellectual function: a follow-up study,” published in the scientific journal Environmental Health, showed lead exposure in childhood affects brain development, resulting in irreversible injury to intellectual functioning in adulthood. In addition, lead exposure through food can injure your nervous system and kidney function, and cause cancer. It can also impact the fetus in a pregnant woman, causing low birth weight, as well as hurting the baby’s cognitive function.

A 2021 study, “Lead Toxicity in Cereals: Mechanistic Insight Into Toxicity, Mode of Action, and Management,” looked at lead in barley, corn, rice, millet, oats, sorghum, and wheat. The research found levels as high as 300 times the maximum permissible limit of 0.2 milligrams per kilogram established by the World Health Organization (WHO). In the U.S., the FDA has not defined a limit to the amount of allowable lead in grains, except in baby food. In 2023, they set new guidelines to reduce the levels of lead in baby food to 10 parts per billion (ppb) for grain-based mixtures, and 20 ppb for dry cereals. This comes two years after a congressional report found dangerous levels of lead, arsenic, mercury, and cadmium in baby food. Cadmium is another dangerous heavy metal. Bread and other wheat-based foods, from pasta to pastries, are a major source of this metal in the American diet. Cadmium can cause bone demineralization, cardiovascular disease, kidney failure, and cancer.

Arsenic is a toxic heavy metal to be aware of if you consume rice or products containing the grain, such as rice milk or rice-based breads. It’s found naturally in groundwater, which is why rice tends to contain this particular toxic element. Rice is grown in flooded fields, where it is exposed to arsenic, and absorbs it. Arsenic is a known human carcinogen. Governments have spent millions of dollars to reduce arsenic levels in water. Yet Americans ingest twice as much arsenic from food than what’s present in drinking water. “Rice consumption contributes to arsenic exposure in US women,” published in the Proceedings of the National Academy of Sciences, revealed that pregnant women could consume more arsenic from a half cup of rice than from a liter of water containing the maximum allowable safe limit for arsenic under federal law. The limit for bottled water is 10 ppb, but the FDA does not have a legal limit on the amount of arsenic allowed in food. Arsenic accumulates in your body, with cancer and skin lesions being common outcomes. Arsenic also causes neurological damage, resulting in lower IQ, as well as learning and behavior difficulties, particularly in children because their bodies are still developing.

Organics and Heavy Metal Exposure

Heavy metals end up in grains because plants absorb them from the soil. As a result, choosing organic over conventionally-grown grains does not mean you’ll avoid the toxic elements. Many factors influence whether an organic farm has high levels of heavy metals. These include how much was present in the soil before the farm was established, and whether it’s near a source of heavy metal contamination. An example would be a location close to a factory or conventional farm where pesticides and fertilizers spill over to the organic farm from water runoff or wind. An organic farmer would need to test their soil to determine the level of dangerous metals present before planting. However, no law mandates such testing be done. In its regulations related to organic farming, the U.S. Department of Agriculture (USDA) merely stipulates:

“[The farmer] must manage plant and animal materials to maintain or improve soil organic matter content in a manner that does not contribute to contamination of crops, soil, or water by plant nutrients, pathogenic organisms, heavy metals, or residues of prohibited substances.”

This means if heavy metals were already present in the soil before the organic farm was established, the farmer is not obligated to test for or remove them. The best way to determine if organic food contains toxic elements is to call the business producing it to ask whether they conduct heavy metal tests, and inquire about the results. Nonetheless, the advantage of organic grains is that pesticides and synthetic fertilizers are not used, meaning less toxins for your body to process. Research found phosphate fertilizer employed by conventional farms contained up to nearly 40 times more lead than farmyard manure used in organic agriculture, increasing the level of heavy metals present in the soil. In addition, studies have shown organic grains contain far lower cadmium levels than grains grown with conventional farming techniques. A scientific analysis, “A Systematic Review of Organic Versus Conventional Food Consumption: Is There a Measurable Benefit on Human Health?” comparing organically-grown food to conventional methods published in the journal, Nutrients, succinctly explained the difference by stating:

“Likely to be of more importance than compositional differences between the two, is what organic foods do not contain. Organic foods have been shown to have lower levels of toxic metabolites, including heavy metals such as cadmium, and synthetic fertilizer and pesticide residues.”

Fortunately, you can take action to thwart the impact of toxic heavy metals to your body. For instance, one step you can take to reduce your exposure to arsenic is to wash rice before cooking. You can also limit your consumption of rice-based products, including rice milk, energy bars made from rice, bread and pastries that contain rich starch, and rice cereal. Where you source your rice plays a role as well. The soil in some regions contain lower levels of heavy metals compared to other locations. Rice varieties from California and Southeast Asia have lower levels of arsenic versus those grown in other parts of the U.S. For example, rice from Arkansas, Louisiana, and Texas have 38% more arsenic than crops from California. Another option is to eat white rice, as it contains 80% less arsenic than brown rice. This is because the toxin tends to accumulate in the bran, which is removed during the production of white rice. On top of that, basmati, jasmine, and sushi rice were found to have lower arsenic levels than other rice types. You can also opt for grains low in arsenic. In the analysis, “How much arsenic is in your rice? Consumer Reports' new data and guidelines are important for everyone but especially for gluten avoiders,” amaranth, buckwheat, millet, bulgur, barley, farro, and polenta contained very little arsenic.

Detoxification

Along with reducing grain consumption and choosing those with lower heavy metal content, you can protect and detoxify your body of these toxic elements. This can be done by absorbing the right nutrients to reduce toxicity. Magnesium helps to decrease the level of cadmium in the kidneys. Vitamins A, C, and E, as well as the minerals selenium, calcium, and magnesium, protect your body from arsenic’s toxic effects. Garlic has been known to possess medicinal properties for centuries. This herb contains sulfur, which detoxifies your liver, helping it eliminate the arsenic in your body. Broccoli, cauliflower, and turnips are also sulfur-containing sources. Consuming foods high in vitamin C, such as citrus, green bell peppers, and all types of berries, is also beneficial. Vitamin C reduces the damage caused by heavy metals by stimulating your body’s production of the antioxidant glutathione. Glutathione detoxifies your body by binding to the heavy metals, so that you can flush them out through your excretory system. From Dr. Axe, “Glutathione Benefits for Longevity & Cancer Fighting: How to Boost?”:

“The key to understanding why glutathione is so crucial for health is that every cell in our bodies produces it. In the words of Gustavo Bounous, MD, retired professor of surgery at McGill University in Montreal, ‘“It’s the [body’s] most important antioxidant because it’s within the cell.”’

Along with alpha lipoic acid, N-acetylcysteine (NAC), sulfur-containing foods, and milk thistle, beef liver is an excellent source of glutathione, and easily absorbable:

“Not only is beef liver a top selenium food, but it has been shown to boost selenium and glutathione production better than supplements. Studies have shown that because the nutrition has been concentrated in the liver, eating this organ from a local grass-fed, organic cow is a highly effective way to boost glutathione levels — plus the levels of selenium in beef and in beef liver are far more bioavailable than supplements.”

In addition, polyphenols, which are naturally occurring micronutrients found in plants, assist against arsenic, and reduce your overall risk of chronic disease. You can get polyphenols from berries, nuts, olives, extra virgin olive oil, and flaxseed. You can also detoxify grains through the use of fermentation. Moreover, fermented foods house probiotics, which help to remove toxic heavy metals from your system by promoting the growth of healthy microbes in your body. Probiotics can be found in yogurt, sauerkraut, kimchi, olives, kombucha, kefir, and pickles. You can also use exercise and/or saunas to sweat out heavy metal toxins. Although sweat is often associated with keeping your body temperature regulated, in Ayurvedic medicine, it has been used as a detoxification tool for centuries. Now, scientific research is validating how sweat acts as a mechanism to cleanse your body. A study published in 2022, “Excretion of Ni, Pb, Cu, As, and Hg in Sweat under Two Sweating Conditions,” analyzed sweat from research participants, and found that metals, such as lead and arsenic, were excreted after exercise. In fact, higher levels of heavy metals were found in sweat than in urine, indicating the former is more effective at eliminating these toxic elements.

If you’re experiencing symptoms such as digestive issues, fatigue, mood swings, or chronic inflammation, these could be signs of heavy metal toxicity. You can partner with a functional medicine doctor to get tested, to help you evaluate the levels of heavy metals in your body, and determine if any are too high. The test is referred to as a heavy metal panel, toxic metals testing, or heavy metal toxicity test. Your healthcare provider must order the test, and will obtain a sample of your blood, urine, fingernails, or hair, depending on which metals they are testing for. If the presence of heavy metals in your body is deemed high, you can work with your integrative practitioner to help you cleanse your body, and to change your diet as needed. One study published in the journal, Nutrients, stated:

“Grains feed the world. However, along with being our main energy and carbohydrate source, grains are also a noteworthy source of dietary contaminants… The complete elimination of such contaminants from grains or any other food product by processing can rarely, if ever, be achieved; hence prevention is more efficient than treatment.”

The paper went on to explain:

“Refining grains will reduce the presence of many contaminants but it also removes 50 to 80% of phytonutrients from whole grains. The observational and preclinical evidence presented here suggests that it is these phytonutrients, (vitamins, minerals and fibres) that may exert a potentially protective effect against mycotoxins and toxic metals in particular. Further, the consumer also has a choice in mitigating any risk from contaminants, and to do so best by continuing to eat a healthy balanced diet, rich in nutrient dense foods. Such a diet will ensure adequate trace mineral status and sufficient intakes of nutrients, antioxidant compounds, phenolics and dietary fibres.”

The current Recommended Dietary Allowance (RDA) for grains is six ounces per day based on a 2,000-calorie diet. Eating different types of grains can be used as a tactic to help you minimize accumulating too much of any one type of heavy metal, while allowing you to eat these starches if you are so inclined. How much grain you eat isn't the only factor in managing the risk of heavy metal toxicity. Unfortunately, grains are not the only foods hosting heavy metals; they can also be found in concentrated fruit juices, dark chocolate, coffee, salt (including sea salt), leafy greens, tea, protein powder, spices, and more. For example, in a 2022 study, “Dietary Intake of Toxic Heavy Metals with Major Groups of Food Products—Results of Analytical Determinations,” black tea infusions were “considered a significant source of toxic heavy metals” for those who regularly drank the beverage.

Stepping Outside the Mainstream

A positive sign is society’s growing awareness of the dangers of heavy metal exposure. In 2024, a new law in California—AB 899 ”Food safety: baby food”—went into effect, requiring the testing of baby food for the presence of heavy metals. It’s the first of its kind in the country. Maryland followed suit in April 2024, becoming the second state to pass such a law—HB 97 “Baby Food – Toxic Heavy Metals – Testing and Labeling,” a.k.a. “Rudy’s Law.” These changes signal forward motion toward establishing accountability and safety in the food supply. While the reality is that you may not be able to completely eliminate the threat of toxic heavy metals, you may consider managing your exposure, and helping your body detoxify through techniques such as boosting polyphenols, to help minimize toxicity. There is no exact science to determine whether or not you’ll build up toxic levels of metals following your current protocol or lifestyle. There are factors, however, to ponder, and take into consideration from here on out: the amount of heavy metals you’ve consumed over time from all food sources, the particular metals you’ve been exposed to, and how well your body flushes them out.

Food for thought: Though there is no one-size-fits-all approach in nutrition, and most would argue there is not one “perfect diet” for every person on the planet, consuming grains is not essential for human health. In “The Problem with Plant Proteins: Grains, Beans, Nuts and Seeds,” Dr. Georgia Ede, M.D., from Diagnosis:Diet exclaims the following:

“For the 2 million years before agriculture was invented, our hunter-gatherer ancestors likely ate few, if any grains, so they are clearly not essential. There have been numerous cultures throughout history (the Inuit Eskimo is a good example) who, even well into the 20th century, ate a completely grain-free diet and were healthy.”

Grains, which incidentally are high in carbohydrates, are known to contain “antinutrients,”—lectins, phytic acid, gluten—proven to cause inflammation and pain, and create a host of health imbalances, particularly in the gut microbiome. Associations have been made from extensive research, linking grain consumption to irritable bowel syndrome (IBS), leaky gut, rheumatoid arthritis, type 2 diabetes, obesity, and heart disease. You can see where this is going … In case you never considered it an option, it’s not such a wild idea to think about letting go of grains altogether, or decreasing your consumption to a large extent. In regards to gluten intolerance, from Dr. Kiltz, “Why Are Grains Bad for You & List of Grains to Avoid”:

“Within 15 hours of consuming glutinous grains, bits of gliadin enter the bloodstream, thus spreading inflammatory damage to other body tissues.

Where then will you get your carbohydrates? They are plentiful in organic fruit (berries are the lowest glycemic)—including squash—raw milk and kefir, raw, local honey (consider your blood sugar), and vegetables, including root veggies such as sweet potatoes, carrots, and beets. By raising your awareness, and staying open to the possibility of change, you’ll be empowered to make decisions from a place of strength and curiosity. If you listen to the cues from your body, they will lead you to your highest fruition in navigating your health. Staying close to the research and making smart choices daily can assist you in alleviating the burden of heavy metal toxicity.

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