Grain-free dog food: who needs it and who does not

Grain-free food is needed by a dog with a confirmed reaction to cereals specifically, and there are few such dogs. Food allergy affects 1–2 % of dogs brought to a vet (Olivry, Mueller, 2017), and among 297 dogs with a confirmed diagnosis a cereal was the allergen in 19 % of cases (Mueller, Olivry, Prélaud, 2016): recalculated, that is 2–4 dogs in 1,000 against 8–16 in 1,000 for animal protein. Between 2014 and November 2022 the US regulator FDA received 1,382 reports of dilated cardiomyopathy in dogs: in the report of 27 June 2019, over 90 % of those foods were grain-free and 93 % contained peas or lentils.

Key points

• Any cereal is an allergen for 2–4 dogs in 1,000 seen by a vet (own recalculation).
• Beef accounts for 34 % of confirmed food allergy cases, chicken 15 %, wheat 13 %, rice 2 % (Mueller, Olivry, Prélaud, 2016).
• In the FDA reports on cardiomyopathy, over 90 % of the foods were grain-free and 93 % contained peas or lentils; the regulator established no causal link.
• The Vet-LIRN laboratory found no difference between grain-free and grain-inclusive foods in protein, fat and taurine on a dry matter basis.
• Starch digestibility after extrusion exceeds 98 % for rice and corn (Carciofi et al., 2008).

Who actually needs grain-free food?

Grain-free food is food without corn, soy, wheat, rice, barley or other cereals: that is exactly how FDA defines the term. It is needed in two cases: when a vet has confirmed a reaction to a specific cereal, and when cereals are removed for the duration of an elimination diet.

Food allergy is a reaction to a protein in food, and only an elimination diet with the food reintroduced confirms it. A blood test does not, and neither does the label on the bag.

The word “hypoallergenic” and the claim “grain-free” are not related. The FEDIAF Code of Good Labelling Practice of 2019 (clause 5.2.2.2) requires a “free from Y” claim to mean the absence of even traces of Y, and adds that such claims must not give the impression that foods containing that substance are unsafe.

How many dogs are allergic to cereals specifically?

Roughly 2–4 dogs in 1,000 brought to a vet are allergic to any cereal. Among 297 dogs with a confirmed diagnosis, wheat was the allergen in 38, corn in 13, rice in 5 and beef in 102 (Mueller, Olivry, Prélaud, 2016).

The share from Mueller, Olivry, Prélaud (2016) multiplied by the 1–2 % prevalence from Olivry, Mueller (2017), own calculation. Upper-bound estimate: some dogs reacted to several foods.

FEDIAF (2025, clause 7.6.4) cautions that a high frequency of individual allergens may simply reflect the fact that dogs eat those proteins most often.

The myth that cereals are the main allergen: what does the arithmetic show?

The claim that cereals are the main allergen and that grain-free food therefore works as prevention does not survive the arithmetic. Take a Border Collie of 3 years, 18 kg, healthy, with no confirmed reaction to food. The chance that cereals are her problem, per the table above, is 0.2–0.4 %.

Now the owner picks a grain-free bag based on chicken. The food removes rice, which 2 % of dogs with allergy react to, and keeps chicken, which 15 % react to.

The claim breaks down where a cereal is swapped for another protein: the rarer allergen is gone and the more common one stays. If a reaction is already there, the order is different: examination, diet, and only then the choice of composition. The signs are covered in the article on symptoms of food allergy in dogs.

Now a different dog, one with a confirmed reaction to wheat. A “grain-free” bag based on peas removes both wheat and rice, which only 2 % of dogs with allergy react to. A food without wheat, with the cereals left in, is enough.

What replaces cereals, and does the food end up with more meat?

Cereals are replaced with legumes and potato, and that does not add protein. The Vet-LIRN laboratory, commissioned by FDA, compared grain-free and grain-inclusive foods: protein, fat, taurine and resistant starch on a dry matter basis “were similar”.

Legumes are peas, lentils, beans and chickpeas. In the FEDIAF labelling code of 2019 they fall under the “Vegetables” category and cereals under “Cereals”, so a pea-based food is formally grain-free. According to FDA, such foods usually contain more legumes.

DELICATE is a manufacturer of dry food for adult dogs from Dnipro: by the label, meat and animal by-products make up at least 60 % of the mix, followed by rice and corn, crude protein is 32 %, and energy is 397 kcal per 100 g (calculated per NRC 2006). There is no wheat, pea, lentil or potato in the composition, so the chicken food is not grain-free as FDA defines it. A 10 kg bag costs UAH 1,188 with delivery: for an 18 kg Border Collie that is 246 g a day, about UAH 29 per day and 40 days per bag. It suits a healthy adult dog from 10 months of age; with a confirmed reaction to chicken or beef the composition is chosen without that protein.
See the food — UAH 1,188

What did FDA find about grain-free foods and dogs' hearts?

FDA established no causal link, but it did collect figures. In July 2018 the regulator announced an investigation into reports of dilated cardiomyopathy in dogs that ate foods with a high share of peas, lentils or potato among the first ten ingredients. The report of 27 June 2019 recorded 524 reports for 2014–2019: 560 dogs and 119 deaths.

Figures from the Q&A of the FDA Center for Veterinary Medicine (current as of 19.08.2024); reports per month are our own calculation. FDA does not name a cause for the spike.

The regulator's position verbatim: “FDA has no definitive information indicating that the diets are inherently unsafe”. The independent data are contradictory: a 2025 narrative review sees the clearest link with legumes, peas above all (Mornard et al., 2025), while an 18-month trial in 60 dogs found no difference in cardiac biomarkers (Morris et al., 2025; funded by Hill's). Questions about a dog's heart are for a vet.

Does a dog digest rice and corn?

Starch digestibility after extrusion exceeds 98 % in all six diets tested by Carciofi et al. (2008): on rice, corn, sorghum, cassava, peas and lentils. Dogs absorbed dry matter and energy best from rice and cassava, and worst from peas and lentils.

The ability to digest starch is inherited. In 392 dogs the median was 10 diploid copies of the pancreatic amylase gene AMY2B against 2 copies in 51 wolves, and each extra copy adds about 5.4 % of serum amylase activity (Arendt et al., 2016). There are exceptions: the Siberian Husky has a median of 3 copies, the Greenland Dog 2.5 and the dingo 2.

How to read a bag labelled “grain-free”?

A food is judged by its ingredient list, and the claim on the front of the bag does not do that job. Three things worth looking at.

• “grain-free” does not equal “wheat-free” and does not equal “hypoallergenic”: there are no thresholds behind those words;
• the first ten ingredients: peas, lentils, chickpeas, beans and potato stood exactly there in 93 % of the foods from the FDA reports;
• with a confirmed reaction to wheat, a food without wheat is enough: there is no need to remove rice and corn along with it.

What to do if you are choosing a bag right now?

• If nobody has confirmed a reaction to cereals, you do not need grain-free food: the chance that cereals are the problem is 2–4 in 1,000.
• If the dog is itching, start with an examination and an elimination diet; swapping bags at random will prove nothing.
• If you are switching to another food, work out the portion: an 18 kg Border Collie needs 246 g a day, and the figure for your dog comes from the portion calculator or the table in the article on how much to feed a dog.

Questions and answers