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Omega-6 : omega-3 ratio in dog and cat diets

A short guide to the role of Omega-6 : omega-3 ratio in dog and cat nutrition.

Omega-6 : omega-3 ratio

Omega-6 and omega-3 fatty acids compete for the same enzymes and for space in cell membranes, which is why the inflammatory profile of the diet is decided not by their amount alone, but by their mutual proportion. The optimal omega-6:omega-3 ratio in the dog and cat is taken to be roughly 5:1 – 10:1 [1] [2]. The meat of land animals is dramatically skewed toward omega-6, so without conscious correction the ratio easily reaches 20:1 and higher.

Why the ratio, not the amount alone

Omega-6 (mainly linoleic acid) drive pro-inflammatory pathways, while omega-3 — above all EPA and DHA — act anti-inflammatorily and competitively inhibit the conversion of omega-6 [3]. A diet can have "enough" omega-6 and at the same time be chronically skewed pro-inflammatory if there is too little omega-3. Diets based on poultry and pork (skin, poultry fat) very easily reach a ratio of 20:1 [4]. That's why limiting the excess of omega-6 is just as important as adding omega-3.

What it means in practice

  • Too high a ratio (too much omega-6, too little omega-3) — the most common BARF problem. Long-term: dull coat, a tendency to skin and joint inflammation, in the cat aggravation of IBD and worsening of kidney function; in puppies and kittens impaired brain and vision development [3]. Solution: add EPA/DHA from small fatty sea fish (sardines, sprats, herrings) 2–3× a week or fish oil, and at the same time limit poultry fat. Both the dog and the cat hardly convert plant omega-3 (flaxseed oil) to EPA/DHA — these are not substitutes [5]. More in the article EPA and DHA.
  • Too low a ratio (extremely much omega-3) — a rarity; with extreme doses of fish oil, clotting disorders and diarrhea are possible [6].
  • Any larger supply of polyunsaturated acids increases the requirement for vitamin E — with a poultry-pork diet and with oil supplementation always monitor it [1]. Store fish oil in the refrigerator; throw out rancid oil. More about the omega-6 side in the articles Linoleic acid and Alpha-linolenic acid.

Sources

  1. National Research Council (2006). Nutrient Requirements of Dogs and Cats. National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
  2. FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. https://europeanpetfood.org/self-regulation/nutritional-guidelines/
  3. Bauer JE (2016). The essential nature of dietary omega-3 fatty acids in dogs. JAVMA 249(11):1267. https://doi.org/10.2460/javma.249.11.1267
  4. Burron S, Richards T, et al. (2024). The balance of n-6 and n-3 fatty acids in canine, feline, and equine nutrition. J Anim Sci. https://doi.org/10.1093/jas/skae143
  5. Bauer JE, Dunbar BL, Bigley KE (1998). Dietary flaxseed in dogs results in differential transport and metabolism of (n-3) polyunsaturated fatty acids. https://doi.org/10.1093/jn/128.12.2641S
  6. Lenox CE, Bauer JE (2013). Potential adverse effects of omega-3 fatty acids in dogs and cats. JVIM. https://doi.org/10.1111/jvim.12033