What Harmful Ingredients Should You Avoid in Dog & Pet Food? (Science-Backed Guide)

Why Ingredient Quality Matters

Pets don’t choose what they eat... we do. The difference between a “balanced diet” and a diet with hidden harmful additives can show up over the years as chronic inflammation, allergies, digestive issues, or organ stress. Many problematic ingredients are cheap shortcuts like additives or fillers that inflate volume or shelf life but carry potential long-term harm when consumed daily.

Below is a breakdown of key ingredients and classes you should avoid or scrutinize... and the science / reason behind the caution.

⚠️ Ingredient Classes to Avoid (and Why)

1. Artificial Preservatives & Synthetic Antioxidants

Common ones include BHA, BHT, ethoxyquin, propylene glycol, TBHQ, and propyl gallate.

These are used to stabilize fats and prevent spoilage/oxidation, but long-term use has been linked to liver and kidney damage, and even cancer in some animal studies.

For example, Dog Food Advisor warns that one of the more controversial preservatives, ethoxyquin, is still used in some pet foods despite concerns over its safety, and that BHA/BHT are considered “suspicious cancer-causing compounds” by some authorities.

Natural alternatives like mixed tocopherols (vitamin E), rosemary extract, or ascorbic acid are safer choices.

2. Generic “By-Products” & Vague Protein Sources

Terms like “meat by-products,” “animal meal,” “meat meal,” or “poultry by-products” are problematic when they are vague. The source, quality, and parts used are often undisclosed.

Some by-products may include undesirable parts like digestive tracts, organs from unhealthy animals, or low-nutrient tissues.

Transparency is key: specific, named sources (e.g. “chicken meat,” “beef muscle”) are preferable.

3. High Grains, Fillers & Plant Proteins (Soy, Corn, Wheat, etc.)

Fillers like corn, soy, wheat often serve as cheap bulk, but they may provide mainly carbohydrate load with low digestibility and contribute to weight gain, glycemic stress, or allergy triggers.

Soy in pet foods has a complex profile. A recent systematic review (2024) shows that when soy is properly processed, it can be comparable in some roles to animal proteins. However, unprocessed or inadequately processed soy has anti-nutritional factors (e.g., trypsin inhibitors, lectins) that interfere with digestion and nutrient absorption, and can be estrogenic in nature.

Soy is a common allergen in pets.

The issue is not always the presence of grains, but how much and in what ratio versus high-quality protein.

4. Artificial Colours, Dyes & Flavour Enhancers

Bright red, yellow, and blue dyes (e.g. Red 40, Yellow 5/6, Blue 2) add visual appeal for humans—but provide no nutritional benefit and may provoke allergic reactions or sensitivities.

Flavour enhancers or “digests” (e.g. animal digest, hydrolyzed proteins) may be derived from unknown animal sources, sometimes from low-grade or heavily processed tissues.

5. High Sugar / Corn Syrup & Sweeteners

Added sweeteners like high-fructose corn syrup, dextrose, or sucrose may make pet foods or treats more palatable, but contribute empty calories, glycemic stress, obesity, and downstream metabolic issues. Some “sugar-free” sweeteners (e.g. xylitol) are toxic to pets—always check explicitly.

6. Carrageenan (In Some Pet Diets/Treats)

While more common in cat/dog wet foods, carrageenan is a thickener that has been shown in in vitro and animal studies to provoke gastrointestinal inflammation and ulceration. (This is more relevant to dog/cat foods than horse feeds.) Because of these concerns, many premium food formulators avoid carrageenan entirely.

🧠 How to Read a Pet Food Label (Practical Tips)

Shorter ingredient lists usually indicate fewer additives.

Named proteins first (e.g. “chicken,” “salmon”) instead of vague “meat meal.”

Additives far down the list — if dyes, artificial preservatives, or sugars appear among the first 10 ingredients, that’s a red flag.

Watch splitting: sometimes fillers are hidden by listing “corn,” “corn gluten,” “corn meal” separately to dilute perception.

Avoid “proprietary blends” — these may hide ingredient amounts.

Check preservative labels: look for terms like “mixed tocopherols,” “ascorbic acid,” or “natural antioxidant” rather than BHA, BHT, ethoxyquin.

🧩 Harmful Ingredients & Horses

While many of the above are most applicable to canine / pet foods, some carry over to equine feeds or supplements:

By-products or vague “meal” sources may appear in lower-grade equine pellets or feed.

Artificial preservatives or colours are rarely necessary in high-moisture, fresh forage-based feeds.

Excessive starches or sugars in concentrates can upset equine digestion (e.g. hindgut acidosis).

Mineral imbalances or high molasses content, sometimes used in commercial feeds, can challenge gut health.

Trisana always emphasizes ingredient transparency, bioavailability, and avoidance of unnecessary synthetic additives.

✅ Why Choose Trisana Nutrition

Our formulations are Vet-health approved under Health Canada’s Veterinary Health Products regime (i.e. compliant with Health Canada’s veterinary standards)

We carefully exclude soy, artificial preservatives, dyes, corn syrups, vague by-products, and carrageenan from our canine supplements.

Our goal: high-quality, bioavailable, transparent ingredients with science-backed doses that support long-term health—not hidden, harmful additives.