Metals

What are heavy metals? Are heavy metals bad for my health?

Scientific Definition

Heavy metals are elements with high atomic weights and densities greater than 5 grams per cubic centimeter (g/cm³). They are characterized by their ability to form cations (positively charged ions) and bond with organic or inorganic molecules. Examples include lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), and chromium (Cr).

While some heavy metals are toxic, others are essential for our biological functions in trace amounts.

Essential (Heavy) Metals

Essential metals are a subset of heavy metals that are necessary for biological processes in humans and other organisms. These include:

• Iron (Fe): Critical for oxygen transport and energy production.
• Zinc (Zn): Supports immune function, cell growth, and wound healing.
• Copper (Cu): Aids in iron metabolism and connective tissue formation.
• Manganese (Mg): Involved in bone formation and metabolic processes.

Heavy Metals in Everyday Conversation

In everyday terms, heavy metals often refer to toxic metals that can accumulate in the body and cause harm, such as lead in paint, mercury in fish, or arsenic in drinking water.

It’s important to distinguish between heavy metals that are harmful (like mercury) and those that are beneficial in small amounts (like zinc).

For most people, the concern lies in limiting exposure to harmful heavy metals while ensuring sufficient intake of essential metals through a balanced diet.

Learn more about Essential Metals and Essential Minerals.

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How do heavy metals get into foods and products?

In general, heavy metals are not intentionally added to foods. Their presence in food is typically unintentional and results from natural sources.

Certain fruits, vegetables, and grains can and do absorb heavy metals during their natural growing process. Even organically grown, non-GMO crops can contain these heavy metals.

This occurs because crops grow in soil, utilize carbon from air, and consume water to thrive. Since soil, air, and water can contain heavy metals both naturally and from industrial activity, the crops are exposed to heavy metals, and the crop takes up the metals during the growing process.

Some crops are more prone to absorbing specific metals than other plants. For example, rice naturally absorbs more arsenic, lettuce and onions accumulate lead more readily, and spinach and carrots accumulate cadmium more easily.

It does not mean all fruits, vegetables, and grains are harmful, and we should avoid eating them—quite the opposite, as fruits and vegetables are essential to a healthy diet.

Remember, the presence of a hazard does not necessarily mean there is a risk. Heavy metals can be present, but at such a low level that they don’t cause harm.

Additionally, we typically consume various fruits, vegetables, and grains grown in different areas, which helps limit our exposure to metals.

Learn more about Heavy Metals in Foods, Heavy Metals in Baby Foods, Heavy Metals in Spices, Essential Metals, and Metals in Tampons.

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Are heavy metals hazardous or risky in foods and products?

Understanding the difference between risk and hazard is crucial in assessing the impact of heavy metals on our health. So, we need to clarify a few concepts:

• Hazard: The inherent property of a substance that makes it capable of causing harm.For example, lead is hazardous because it can damage the nervous system. In cosmetics, lead contamination poses a hazard due to its potential to cause cumulative harm over time.
• Risk: The likelihood of harm occurring under specific conditions of exposure. Risk considers both the hazard and the level of exposure.Risk is calculated using the formula: hazard X exposure = risk.For instance, trace amounts of lead in a cosmetic product may present a low risk if exposure is minimal, whereas chronic exposure to higher levels in contaminated water can significantly elevate the risk of adverse health effects.

Assessing risk

In order to understand risk, researchers and health policy creators use a formalized risk assessment process.

The process of evaluating risk involves:

1. Identifying the Hazard: Determining the harmful properties of the substance.
2. Assessing Exposure: Understanding how much of the substance people are exposed to and through what pathways (e.g., ingestion, inhalation, or skin contact).
3. Characterizing Risk: Estimating the likelihood and severity of adverse effects based on exposure levels. For example, risk assessment in foods considers consumption frequency and contamination levels.

Making risk-informed decisions

Once we know the risk in real terms, we can use our knowledge to make informed decisions.

We know that foods and products often contain naturally occurring heavy metals, but at levels that don’t meaningfully increase the risk of adverse health outcomes. Additionally, we know that without a balanced diet full of fruits and vegetables, we’re likely to experience adverse health outcomes. So, it makes sense to eat nutrient-dense foods even if they contain trace amounts of undesired heavy metals.

Learn more about risk: What is risk?, Using risk to make informed decisions, Zero risk?, Exploring the risk assessment process.

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How do I reduce heavy metal exposure?

Minimizing your exposure to heavy metals involves a few straightforward steps:

• Test your drinking water. Check for heavy metals in your water supply, especially if you rely on well water. Knowing your water’s safety levels helps you take corrective action if needed.
• Assess your home. If you live in an older house, test the paint for lead. This is important to determine if remediation is necessary to protect yourself and your family from potential lead exposure.
• Check your soil. If you’re planning on growing an edible garden, test your soil for heavy metals to ensure it’s safe for cultivating edible plants. If contaminants are present, you can adjust your gardening methods accordingly.
• Diversify your diet. Eating a variety of foods is one of the simplest ways to stay within safe heavy metal levels. A wholesome, balanced diet reduces the risk of consuming excessive amounts of metals (or any nutrient) from a single source.

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What do heavy metals have to do with California AB899?

California AB899 is a law aimed at informing the public about the presence of heavy metals in foods, beverages, and supplements made for babies and toddlers.

This legislation requires manufacturers to:

• Test products for four heavy metals: lead, cadmium, arsenic, and mercury.
• Share the results publicly on a website. Parents can access this information easily via a QR code or URL on the product packaging.

What AB899 does NOT do:

• It does not set safe limits for heavy metals like cadmium, lead, arsenic, or mercury.
• It does not standardize how test results are reported, meaning manufacturers may use different units, which can be confusing.
• It does not provide guidance to help parents understand the results or how they relate to safety.

Why It Matters

Detection does not mean harm, just as hazard does not mean risk. Many nutritious foods naturally contain trace amounts of heavy metals at levels too low to impact safety or nutrition.

Eating a balanced, diverse diet rich in fruits, vegetables, proteins, and healthy fats is essential for overall health. And, the trace amounts of heavy metals in these foods do not change this recommendation.

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Measuring metal levels in foods and products.

Metals can be measured in foods, beverages, personal care products, and household items using different scientific methods. As with most things in science, there isn’t a single way to measure metal content—various units and measurement systems are used. This can sometimes be confusing when you see different readouts.

To make it easier, the tables below provide quick reference charts to help you understand and convert between common measurement units.

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