"Low in Heavy Metals" on a Pet Food Label: What It Means

The short answer

You may see wording like "low in heavy metals" or "tested for heavy metals" on a bag or a product page. Here's what the sources we reviewed show about it.

Label wording has to be truthful. Under federal law, a food is misbranded if its labeling is false or misleading in any particular, and AAFCO's guidance says pet food claims must be truthful and not misleading. AAFCO also says it has no approval step for claims. Its label guide sets definitions for words like "lite," but heavy metal wording isn't among the descriptors it lists. And the FDA has not set heavy metal limits for animal food.

So "low" needs a comparison, and the brand should be able to show it.

Who checks what's printed on a pet food bag

The FDA says pet food labeling is regulated at two levels. Federal rules require the product's identity, the net quantity, the name and place of business of the maker or distributor, and the ingredients listed from most to least by weight. Some states also enforce their own labeling rules, and many of those are based on a model from AAFCO.

The FDA also reviews certain specific claims. Its examples are "maintains urinary tract health," "low magnesium" and "hairball control." Heavy metal wording isn't among the examples the FDA gives.

Federal misbranding law applies too. In plain words, if any part of a food's labeling is false or misleading, the food is misbranded.

So who decides whether a given label passes? AAFCO's page on marketing claims is direct about it. AAFCO has no steps for a company to get approval to make claims on a pet food label. It is the job of the state feed control official to decide whether a label is acceptable under that state's feed law.

Our post on who regulates heavy metals in pet food explains how the FDA, the states and AAFCO split the work.

Words with definitions, and words without

Some label words have set meanings. AAFCO's guide to reading pet food labels lists descriptors such as "lite," "lean or low fat" and "less or reduced" fat or calories. Each comes with criteria. A "lite" product has a calorie ceiling, for example, and a "reduced" claim has to name the product it's being compared with.

The same guide covers comparisons more broadly. A statement comparing one product's characteristic with another's must be substantiated. It's limited to one year of production, after which the claim must be removed or substantiated again. And any false or misleading comparison to another product is prohibited.

Heavy metal wording isn't in that descriptor list. We searched the guide's text for "heavy metal," "arsenic," "cadmium" and "mercury," and none appeared. That doesn't mean such wording is allowed or forbidden. It means the guide doesn't give "low" a set meaning for metals the way it does for fat or calories.

So the useful question is the one a "reduced" claim already has to answer: low compared to what? Compared to another product, to an earlier recipe, to a lab's reporting limit or to a reference value? Each is a different claim. The FDA's report on heavy metals in animal food says it has not issued guidance, action levels or tolerances for heavy metals in animal food, so there's no official US number for "low" to be measured against.

What a label can tell you, and what it can't

A label tells you what a company says about its food. A test result tells you what a lab measured in a sample. Both are useful, and they answer different questions.

The nutritional adequacy statement is about something else. The FDA explains that the nutritional adequacy statement tells you whether a food is meant to meet a pet's nutritional needs. That's nutrition, not metals. Our post on heavy metals in kitten food covers what that statement means for growing pets.

There is one precedent where the FDA tied a lead claim to testing, and it's about dishes, not pet food. In FDA guidance on imported traditional pottery, the FDA said that if ceramicware labeled as having no lead contains extractable lead when tested, it may consider that wording false and misleading. The point for pet owners is simple: wording on a product isn't a test result. Results are what show amounts.

Five questions that make a claim checkable

A heavy metal claim becomes useful when the brand can answer these:

1. Which metals? A claim should say which were tested, such as lead, arsenic, cadmium or mercury.
2. Which lab? Was it an independent lab, and what method did it use?
3. Which batches, and how often? One result describes one sample.
4. Compared to what? Ask whether the numbers are as fed or dry matter, and what they're being compared with. Our guide on how to read pet food heavy metal test results walks through this.
5. Will you share the results?

For more on what happens in the lab, see our post on how pet food is tested for heavy metals. To fit these questions into choosing a food, see how to check cat food for heavy metals.

Reading a certification mark

A certification mark is also something to read. It tells you a program is involved. The program's own pages should say what it tests, how often, against what and how results are shared with owners.

The same goes for phrases like "third-party tested." Our guide on what third-party tested means explains what that wording does and doesn't tell you. It was written for supplements, but the questions carry over.

FAQ

Is "low in heavy metals" an official term? The descriptor list in AAFCO's label guide doesn't include it. Claims still have to be truthful and not misleading under AAFCO's guidance and federal law.

Does anyone approve pet food claims before they're printed? AAFCO says it has no approval step for claims. State feed control officials decide whether a label is acceptable under state law. The FDA reviews certain specific claims, such as urinary tract health claims.

Can a label tell me how much of a metal is in the food? No. A label isn't a test result. The FDA notes that heavy metals are found in air, water and soil, and that removing them entirely from animal food is not always possible. Test results, with their reporting limits, are what show amounts.

What should a good claim tell me? Which metals were tested, by which lab, in which batches and how often, what the results are compared to and whether the brand will share them.

A note on your pet's health

This article is general information, not veterinary or legal advice. If you have questions about your pet's diet, contact your veterinarian.

Want results you can check?

Heavy Metal Tested is a certification program that helps brands share independent results with owners. Learn how certification works.