Colours, palatants and additives in pet food: a guide

Colours: A meat-red chunk, a vegetable-green pellet, a savoury aroma the moment the bag opens: much of what makes a pet food look and smell appealing is added on purpose. Some of it serves the animal, some serves only the human buyer, and a small number of cases are genuinely worth caution. The disciplined way to read these additives is to separate two questions that marketing tends to merge: is it useful, and is it safe? A colourant can be safe yet useless, while a palatant can be both safe and genuinely helpful to a sick animal.

Petipedia · Editorial team

General documentary information. For an individual animal, a veterinarian's advice takes precedence over any online content.

This guide works through colours, palatants and flavourings, sugar and salt, and the technological additives that give wet food its texture. It keeps EU and US status distinct, dates the regulatory cases that are settled, and gives the level of evidence for each. No additive discussed here is shown to be dangerous at authorised doses; the differences lie in utility and in a few open files.

On this page (Colours palatants)

• Do colourants do anything for the animal?
• Are palatants and meat digests a bad sign?
• Natural versus artificial flavourings: does origin change safety?
• Do sugar and salt belong in the bowl?
• Are thickeners such as carrageenan harmful?
• Which colour and additive cases are genuinely settled?
• Comparison: utility versus safety across additive families
• The verdict: ask "useful?" and "safe?" separately

Do colourants do anything for the animal?

Answer capsule. No. Dogs and cats have dichromatic vision, are little sensitive to red and green shades, and choose food by smell and taste, not appearance (WSAVA). A colourant therefore meets no animal need; it serves the human buyer's eye. It remains authorised and shows no demonstrated harm at usual doses, but it offers no nutritional value.

A coloured kibble is, in effect, a presentation argument. The meat-red tone or vegetable-green fleck communicates something to the shopper and nothing to the animal eating it. Removing a colourant changes only the product's appearance, never its nutritional value, which is why the absence of colour is a neutral fact rather than a benefit.

The evidence for harm from authorised colourants at usual doses is weak, and where doubt has appeared the additive has been withdrawn, as with titanium dioxide (Regulation (EU) 2021/2090). For colourants, then, the honest framing is utility and transparency, not hazard: nil value to the animal, low risk at usual doses.

Are palatants and meat digests a bad sign?

Answer capsule. No, not in themselves. A meat digest or hydrolysate is an animal protein pre-digested enzymatically, releasing savoury peptides and amino acids that are sprayed onto the kibble to raise acceptance (FEDIAF, 2024). It is a common, authorised technology with no demonstrated harm at usual doses. Its presence signals work on palatability, not a quality defect.

Unlike a colourant, a palatant can serve the animal directly. Restarting intake in a fussy cat or a convalescent dog is a genuine health goal, and palatability is the lever that does it (WSAVA). A flavour that helps an anorexic cat eat again can matter more to its health than the cosmetic presence or absence of a colour.

A reassuring detail: hydrolysed proteins are also used, in another form, in hypoallergenic veterinary diets, which shows that hydrolysis is a mastered technique rather than a suspect shortcut. The evidence on the safety of hydrolysed palatants at usual doses is solid. The real quality criterion remains the overall balance of the ration, not the presence of a palatant.

Natural versus artificial flavourings: does origin change safety?

Answer capsule. No. A natural flavouring comes from animal or plant matter, such as a poultry digest or a yeast extract; an artificial flavouring is synthesised to reproduce a taste. Both serve palatability, both are governed by EU positive lists assessed by EFSA, and at use doses neither is shown to be dangerous (EFSA). Origin does not predict safety.

This is one of the clearest places where "natural" is read as "safer" without warrant. Safety depends on the toxicological assessment of each specific substance, not on whether it was extracted or synthesised. Some natural compounds can be more chemically reactive than their purified synthetic counterparts, so the natural label is no guarantee in either direction.

For the animal, what matters is that the flavouring is authorised and correctly dosed. The evidence shows safety resting on per-substance assessment, with both natural and synthetic flavourings held to the same positive-list framework. The distinction is one of process and marketing, not of risk.

Do sugar and salt belong in the bowl?

Answer capsule. They differ. Added sugar has no useful nutritional role: it supplies empty calories and dogs and cats have no physiological need for it, though it is not toxic at usual doses (FDA; AAFCO). Salt, by contrast, supplies sodium and chloride, essential electrolytes with requirements set by the NRC and FEDIAF, and is not dangerous to a healthy animal at the levels found in complete foods (NRC, 2006).

For sugar, the issue is energy balance rather than poison. Chronic excess promotes overweight and, indirectly, feline diabetes (WSAVA). Sugar or caramel sometimes appears as a palatant or brown colourant in treats and wet foods, cosmetic uses rather than nutritional ones, and a very sweet treat given daily can be a non-trivial share of a small dog's calories. The useful rule is to keep treats to a small fraction of the daily ration.

For salt, the fear of dietary-salt hypertension as seen in some humans is not established in dogs and cats, which tolerate a wide sodium range and excrete the surplus through the kidneys (Tufts Petfoodology). The acute risk comes from massive accidental intake, such as salt dough or seawater, not from a kibble's salt level. Restriction is a medical decision in advanced cardiac or renal disease, on prescription, not a routine precaution.

Are thickeners such as carrageenan harmful?

Answer capsule. Not at authorised use doses. Emulsifiers and thickeners such as guar gum, xanthan gum, carrageenan and modified starches give wet food its texture and hold, and are assessed by EFSA before authorisation (FEDIAF, 2024; EFSA). No general harm to cats is shown at the quantities used, although carrageenan specifically remains debated.

The carrageenan debate is worth stating precisely, because it is the one open file in this family. The controversy turns on a confusion between two substances: food carrageenan, of high molecular weight, and poligeenan, its degraded form produced under high heat and acid hydrolysis. It is poligeenan, not the additive in use, that concentrates the irritation signals seen in the laboratory (PubMed literature). Excretion work suggests a large share of intact carrageenan is eliminated without significant degradation.

Agencies maintain food carrageenan's authorised status, GRAS in the United States and authorised in the EU, with targeted restrictions only on certain sensitive human uses such as infant formula, not on foods for domestic carnivores (FDA; EFSA). Guar and xanthan gums raise no comparable controversy. The evidence for harm from these thickeners at use doses is weak, and the one genuinely debated case should not discredit the rest.

Which colour and additive cases are genuinely settled?

Answer capsule. A few, and each is backed by a dated regulation. Titanium dioxide (E171) as a feed colourant was refused in the EU by Regulation (EU) 2021/2090, with stocks withdrawn by 20 March 2022, after EFSA could no longer rule out genotoxicity from nanoparticles in May 2021 (EUR-Lex; EFSA, 2021). Propylene glycol (E490) is banned for cats, where it promotes Heinz bodies and red blood cell damage, while remaining permitted for dogs under conditions (FDA, 21 CFR 589.1001).

These cases share a pattern that distinguishes a real decision from a slogan. Titanium dioxide had been authorised for dogs and cats without a time limit, then was withdrawn not on proof of harm but on the impossibility of guaranteeing safety, a direct application of the precautionary principle. An old authorisation, in other words, is never final.

Propylene glycol illustrates a second pattern: status by species. One molecule can be a legal additive for the dog and a banned adulterant for the cat, because feline red blood cells are more vulnerable to oxidative stress (FDA). The evidence in both cases is regulatory, dated and species-aware, which is precisely what marks a settled concern.

Comparison: utility versus safety across additive families

The table separates the two questions this guide keeps apart. Reading down the "utility" and "risk" columns shows why colourants and palatants should never be lumped together, and where the genuinely settled restrictions sit.

The verdict: ask "useful?" and "safe?" separately

The evidence supports a calm, two-question reading. On safety, no additive in this guide is shown to be harmful to a healthy dog or cat at authorised doses, and the genuinely settled restrictions, titanium dioxide as a feed colourant and propylene glycol for cats, are few, dated and specific (Regulation (EU) 2021/2090; FDA, 21 CFR 589.1001). On utility, the families diverge sharply: colourants do nothing for the animal, palatants and flavourings serve palatability, salt is an essential nutrient, and added sugar is empty calories to moderate.

The recommendation follows from keeping those questions apart. Do not treat the presence of a colourant as a danger, but recognise it adds nothing for your pet. Welcome a palatant if it helps a fussy or recovering animal eat. Moderate sugary treats by the calorie share they represent rather than scrutinising every gram. Leave salt restriction to a veterinary cardiac or renal context. And never feed a dog product containing propylene glycol to a cat. For the one open file, carrageenan, the food form is authorised and no hazard is demonstrated at use doses, so it warrants attention rather than alarm.

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Keep reading

Related questions: Do colourants and palatants added to kibble pose a problem? | Is the carrageenan in cat wet food dangerous? | Is propylene glycol permitted for dogs but banned for cats?

Glossary: Palatants and flavourings | Colourants (US: colorants)

Hub: Controversial ingredients: myths versus evidence

Sources: WSAVA Global Nutrition Guidelines; FEDIAF Nutritional Guidelines 2024; EFSA, sensory and technological additives, re-evaluations of carrageenan (E407) and titanium dioxide (2021); FDA, pet food and 21 CFR 589.1001; Regulation (EU) 2021/2090 and Regulation (EC) 1831/2003 (EUR-Lex); NRC, Nutrient Requirements of Dogs and Cats (2006); Tufts Petfoodology; PubMed literature on poligeenan.