Heavy metals are in your food, water, cookware, and cosmetics. Here's what to actually worry about and what to do.
Lead in baby food. Arsenic in rice. Mercury in fish. Cadmium in chocolate. The headlines are alarming, and they're not wrong. A 2021 Congressional report found that major baby food brands contained dangerous levels of arsenic, lead, cadmium, and mercury—and the companies knew about it.
But the question most people really need answered isn't "are heavy metals everywhere?" (They are.) It's: how much exposure matters, how do I know if I'm affected, and what can I actually do about it?
Both conventional toxicology and functional medicine have answers. They just approach the problem differently.
The Big Four: Which Metals Matter Most
Lead
There is no safe level of lead exposure. The CDC has acknowledged this since 2012. Lead accumulates in bones (half-life of 20-30 years) and damages the nervous system, kidneys, and cardiovascular system. Common sources include old paint and pipes, imported ceramics, some spices (especially from South Asia), and contaminated soil.
Mercury
Methylmercury in large predatory fish (swordfish, shark, king mackerel, tilefish, bigeye tuna) is the primary dietary source. Mercury is also released from dental amalgam fillings—a controversial topic where conventional and functional medicine often diverge. Symptoms include brain fog, tremors, numbness, and mood changes.
Arsenic
Inorganic arsenic (the dangerous form) concentrates in rice, rice products, apple juice, and groundwater in certain regions. Chronic exposure increases risk of bladder cancer, skin lesions, cardiovascular disease, and diabetes. The US has no federal limit for arsenic in most foods.
Cadmium
Found in chocolate, leafy greens grown in contaminated soil, cigarette smoke, and some fertilizers. Cadmium targets the kidneys and bones and has a biological half-life of 10-30 years. Even low-level chronic exposure is linked to kidney dysfunction and osteoporosis.
Symptoms of Chronic Low-Level Exposure
This is where the conventional-functional divide gets interesting. Acute heavy metal poisoning has clear, dramatic symptoms. But chronic low-level exposure—the kind most people actually experience—produces vague, overlapping symptoms that conventional medicine often attributes to other causes:
- Persistent fatigue and brain fog
- Headaches and migraines
- Digestive issues (nausea, constipation, metallic taste)
- Joint and muscle pain
- Mood changes, anxiety, irritability
- Difficulty concentrating and poor memory
- Tingling or numbness in extremities
- Unexplained skin rashes
- Recurrent infections (immune suppression)
A conventional internist seeing this list might order a CBC and thyroid panel. A functional medicine practitioner will also consider environmental exposures and order appropriate testing.
How to Test for Heavy Metals
Testing methodology matters enormously, and this is an area where misinformation abounds:
Blood Testing
Best for: Recent or ongoing exposure to lead and mercury. Blood lead and blood mercury are the gold standard for active exposure assessment. This is what conventional toxicology relies on, and it's reliable for what it measures.
Urine Testing
Unprovoked urine: Useful for arsenic and cadmium. A 24-hour or first-morning urine collection reflects recent intake and kidney excretion. This is accepted by both conventional and functional practitioners.
Provoked urine (chelation challenge): This involves taking a chelating agent (like DMSA or DMPS) and collecting urine afterward. Functional medicine sometimes uses this to assess body burden. Conventional toxicology criticizes this method because chelation mobilizes metals from tissue, producing artificially elevated readings without established reference ranges. Use provoked testing cautiously and only with an experienced practitioner.
Hair Mineral Analysis
Popular in functional medicine circles but controversial. Hair reflects exposure over months, but results can be affected by hair treatments, shampoos, and external contamination. The CDC does not recommend hair testing for clinical decisions. Some functional practitioners find it useful as a screening tool when interpreted by an experienced provider.
Protective Nutrients: Your Daily Defense
Your body has natural detoxification systems. Specific nutrients enhance them:
Selenium
Selenium binds directly to mercury, forming an inert compound (mercury selenide) that your body can safely excrete. Brazil nuts are the richest food source—just 2-3 per day provides adequate selenium. This is one reason why eating selenium-rich foods alongside fish is protective.
Zinc
Zinc competes with cadmium and lead for absorption sites in your intestines. Adequate zinc status literally blocks heavy metal uptake. Oysters, beef, pumpkin seeds, and lentils are top sources. Many Americans are marginally zinc-deficient.
N-Acetyl Cysteine (NAC)
NAC is the precursor to glutathione—your body's master detoxification molecule. Glutathione binds heavy metals and facilitates their excretion through bile. NAC at 600-1200mg daily has been shown to reduce oxidative damage from metal exposure. It's used in emergency rooms for acetaminophen overdose and by functional medicine practitioners as a daily detox support.
Additional Protective Nutrients
- Vitamin C — chelates lead and reduces oxidative damage from metal exposure
- Chlorella — binds metals in the GI tract, reducing reabsorption (modest evidence but low risk)
- Modified citrus pectin — shown in human studies to increase urinary excretion of lead and arsenic
- Alpha-lipoic acid — crosses the blood-brain barrier and chelates mercury (use cautiously and with guidance)
- Fiber — prevents reabsorption of metals excreted through bile into the intestines
Chelation Therapy: When Is It Warranted?
Conventional medicine reserves chelation for acute poisoning with documented elevated blood levels. EDTA, DMSA, and DMPS are FDA-approved chelating agents used in emergency and clinical settings.
Functional medicine sometimes uses low-dose oral chelation for chronic low-level exposure, though evidence for this application is more limited. The important principles:
- Never chelate without confirmed testing showing elevated levels
- Always ensure mineral repletion (chelators can remove beneficial minerals too)
- Support elimination pathways (liver, kidneys, gut) before mobilizing metals
- Work with an experienced provider—improper chelation can redistribute metals into the brain
Practical Steps to Reduce Exposure Today
- Rinse rice thoroughly and cook in excess water (6:1 ratio), draining the excess. This removes up to 60% of inorganic arsenic.
- Vary your grains—don't eat rice at every meal. Rotate with quinoa, millet, buckwheat, and oats.
- Choose smaller fish—sardines, anchovies, wild salmon, and trout are low in mercury and high in omega-3s.
- Filter your water—a reverse osmosis or activated carbon filter removes most heavy metals. NSF-certified filters are your best bet.
- Check your spices—buy from reputable brands that test for heavy metals. Turmeric, chili powder, and paprika are high-risk categories.
- Ditch non-stick and aluminum cookware—use stainless steel, cast iron, or ceramic instead.
The Bottom Line
Heavy metal exposure is a real and underappreciated contributor to chronic disease. The dose makes the poison, but the duration matters too. Low-level exposure over decades accumulates in ways that standard medical testing often misses.
The best approach combines conventional testing for acute concerns with functional medicine's emphasis on prevention, nutritional protection, and root-cause investigation when symptoms don't match standard diagnoses.
You can't avoid every heavy metal in the modern world. But you can dramatically reduce your exposure and give your body the tools it needs to handle what gets through.