10 Pet Food Ingredients Vets Wish You'd Avoid

Pet food ingredient lists can run 30–40 items long. Most of them are fine. A handful — the ones on this list — come up repeatedly in veterinary discussions about long-term pet health.

This isn't fearmongering. Most pets eat foods containing these ingredients and live perfectly healthy lives. The goal here is informed awareness: knowing what these ingredients are, what the concerns are, and what to substitute when good alternatives exist.

1. BHA and BHT

Full names: Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) Used as: Synthetic antioxidant preservatives for fats

BHA is listed by the US National Toxicology Program as "reasonably anticipated to be a human carcinogen." BHT has similar concerns at higher doses. Both are still legal in pet food.

The functional alternative — mixed tocopherols (vitamin E) — is widely available, effectively extends shelf life, and has no known safety concerns at dietary levels. Most premium brands switched years ago. If a mid-to-high-price product still lists BHA or BHT, that's a formulation decision worth noting.

2. Ethoxyquin

Used as: Preservative for fish oils and fish meals

Ethoxyquin was developed as a pesticide and rubber stabilizer before being approved as a food preservative at low levels. It's still permitted in pet food in the US and EU at specific concentrations.

The concern isn't acute toxicity at label amounts — it's the precautionary principle. Better-studied and safer alternatives (mixed tocopherols, ascorbic acid) exist and are used by most reputable fish-based pet food manufacturers.

The sneaky issue: ethoxyquin applied to fish meal before delivery to the manufacturer doesn't legally need to appear on the pet food label. You may be getting it even when it's not listed.

3. Carrageenan

Used as: Thickener and gelling agent in wet pet food

Degraded carrageenan (poligeenan) has been shown to cause gastrointestinal inflammation in animal studies. Undegraded carrageenan (the type used in food) is GRAS-rated by the FDA.

The problem: under acidic stomach conditions, undegraded carrageenan can convert to the degraded form. For pets with IBD, chronic GI issues, or sensitive stomachs, many veterinary nutritionists recommend avoiding it — even if the absolute risk for healthy animals is low.

Alternatives: guar gum, locust bean gum, agar-agar. If your pet has chronic GI issues and you see carrageenan in their food, it's worth a trial elimination.

4. Propylene glycol (in cat food specifically)

Used as: Humectant; prevents moisture loss in semi-moist food

The FDA banned propylene glycol from cat food in 1996 after it was shown to cause Heinz body anemia (red blood cell damage) in cats. It is still legal in dog food.

The risk: you may not know if your multi-cat, multi-dog household has products that cross-contaminate. Semi-moist dog treats are common propylene glycol sources. If a cat ingests dog food with propylene glycol regularly, it's a cumulative risk.

Check every semi-moist dog treat in your home if you have cats.

5. Generic "meat meal" and "poultry meal"

Used as: Protein source

Not an additive — a protein quality issue.

As discussed in our chicken meal vs. chicken article, unnamed meals provide no species traceability. "Meat meal" can legally come from any mammal — including 4-D sourced animals (dead, dying, diseased, or disabled before slaughter).

This is less a toxicity concern and more a quality and consistency concern. For pets with protein allergies, unnamed meals make elimination diets impossible. For any pet, named meals (chicken meal, salmon meal) are categorically preferable.

6. Artificial colors (Red 40, Yellow 5, Blue 2)

Used as: Color additives — for human appeal, not pet appeal

Dogs and cats are not particularly responsive to food color. Artificial colors in pet food exist solely to make kibble look more appealing to the person buying it.

Red 40, Yellow 5, and Blue 2 are FDA-approved at permitted levels with limited evidence of harm at typical doses. However, some animal studies have linked them to behavioral changes and hypersensitivity. The European Food Safety Authority requires warning labels on human food containing certain azo dyes.

The rational response: there's no benefit to artificial colors in pet food. A food using them is making a formulation choice that prioritizes aesthetics over cleanliness. Better alternatives — natural colorings from turmeric, beet, etc. — exist.

7. Onion and garlic powder

Used as: Flavoring agents

This one is unambiguous: onion and garlic are toxic to both dogs and cats in any form — raw, cooked, dried, or powdered. They belong to the allium family and cause oxidative damage to red blood cells, leading to hemolytic anemia.

The danger with garlic powder specifically:

It's 5× more potent than raw garlic per gram
Small daily doses accumulate — chronic exposure at "small" amounts is more dangerous than a single large exposure
It appears in some "natural" pet treats marketed as breath fresheners

Garlic and onion powder should never appear in a food or treat you give your dog or cat. If you see them, move on immediately.

8. Corn syrup and added sugars

Used as: Palatability enhancers; binding agents

Corn syrup and other added sugars (molasses, fructose, glucose) in pet food serve the same function as in human processed food: they make a cheaper product taste better. They also contribute to:

Obesity (a major health issue for cats and dogs)
Dental disease
Potential blood sugar instability in diabetic or pre-diabetic animals

Sugars occasionally appear in treats and semi-moist products under names like "cane molasses," "sucrose," or simply "sugar." For any pet with diabetes, obesity, or dental disease, this is a meaningful flag.

9. Sodium nitrate (in treats and processed meat products)

Used as: Preservative and color fixative in processed meat-based treats

Sodium nitrate preserves meat and gives cured products their characteristic red color. The concern: under high-heat cooking, nitrates can convert to nitrosamines — compounds that are carcinogenic in animal studies at high doses.

It's not common in complete pet foods, but it appears in processed meat treats: jerky, sausage rolls, deli-style treats. If treats are a regular part of your pet's diet, check for sodium nitrate.

10. Rendered fat with unspecified source

Used as: Palatability enhancer; energy source

"Animal fat" without a named source is the fat equivalent of "meat meal" — no traceability, variable quality, and potential for inconsistency. "Chicken fat" or "salmon oil" are named alternatives.

The practical concern: rendered fat from mixed sources may have higher contamination risk and is more variable in fatty acid composition. For most healthy pets, it's not a crisis — but for pets with pancreatitis, fat quality and consistency matter.

A note on context

Finding one of these ingredients in your pet's food is not an automatic reason to panic or switch foods abruptly. Most pets eating foods with these ingredients live long, healthy lives. Abrupt food changes cause GI upset. And some of these ingredients (carrageenan, BHA) are present in trace amounts that may carry minimal practical risk for healthy animals.

The goal is to use this list as a tiebreaker — when you're comparing two otherwise equivalent foods, prefer the one without these ingredients. And for pets with existing health conditions, the bar for flagged ingredients is higher.

Pawpoy automates this check: scan any food and we flag every ingredient on this list, along with the specific reason and whether it's relevant to your pet's health profile.

Check your pet's food for these ingredients →

This article is general educational guidance and does not constitute veterinary advice.