Holistic Health Hub

The Science of Fatty Acid Conversion in Dogs and Cats

Fatty acids are essential nutrients for both dogs and cats, but not all fatty acids act the same way in the body. In animal nutrition, much attention is given to how efficiently certain plant-based fatty acids are converted into their biologically active forms. Two common examples are:

  • The conversion of alpha-linolenic acid (ALA, an omega-3) into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

  • The conversion of linoleic acid (LA, an omega-6) into arachidonic acid (AA).

Because these conversions are often inefficient, it is important to recognise ALA and LA as essential fatty acids in their own right — not just as precursors to EPA, DHA, or AA.

Conversion Pathways

  • ALA (omega-3) is converted into EPA at an efficiency of around 1–10%, and into DPA (docosapentaenoic acid) at less than 1%. Conversion into DHA is extremely limited. This pathway relies on the enzymes delta-6 and delta-5 desaturase.

  • LA (omega-6) also uses the same enzymatic pathway to produce gamma-linolenic acid (GLA) and AA. Because these conversions share the same enzymes, competition occurs. If LA is high in relation to ALA, it can reduce the production of DHA precursors from ALA.

This means that diets low in animal sources of EPA, DHA, and AA cannot rely solely on ALA and LA to meet a pet’s omega-3 and omega-6 requirements.

Beneficial Fatty Acids from LA (Omega-6)

  • Linoleic Acid (LA) – supports skin, coat, and reproductive health when fed in the correct balance.

  • Gamma-Linolenic Acid (GLA) – supports hormone function, skin integrity, and acts as a precursor to anti-inflammatory dihomo-gamma-linolenic acid (DGLA).

Plant-based oils such as hempseed, evening primrose, or ahiflower oil can supply GLA and encourage the body to produce more DGLA.

Beneficial Fatty Acids from ALA (Omega-3)

  • Alpha-Linolenic Acid (ALA) – helps maintain healthy skin and coat by supporting the skin’s moisture barrier.

  • Stearidonic Acid (SDA) – anti-inflammatory, supports cardiovascular health.

  • Eicosatetraenoic Acid (ETA) – powerful anti-inflammatory, may support cartilage repair and immune balance.

  • Eicosapentaenoic Acid (EPA) – key anti-inflammatory fatty acid with an important role in immune function.

Although conversion is inefficient, ALA contributes to overall anti-inflammatory support, especially when supported by cofactors such as zinc, magnesium, vitamin C, and vitamin B6.

Conversion in Cats

Cats are unique because they have very little delta-6 desaturase activity:

  • AA (arachidonic acid) was once considered fully essential for cats, since they cannot convert LA efficiently. Research shows they may use alternative pathways, allowing adult cats to produce small amounts of AA for maintenance — but not enough for reproduction.

  • ALA to DHA conversion is essentially absent. Cats can produce only trace amounts of EPA and DPA, but not DHA. Therefore, cats must receive EPA, DHA, and AA directly from animal sources such as fish oil, egg yolk, or organ meats.

  • These limitations are especially pronounced in kittens, who have a conditionally essential requirement for preformed AA, EPA, and DHA.

Anti-Inflammatory Roles of ALA and LA

  • ALA – while conversion to DHA is poor, ALA-derived metabolites like SDA and ETA have direct anti-inflammatory benefits. Supporting their production with cofactors (zinc, magnesium, vitamin C, B6) enhances these effects.

  • LA – when balanced correctly, LA helps produce GLA and ultimately DGLA, which are anti-inflammatory. However, when excessive LA is present without sufficient EPA, DHA, or ETA, it may instead be directed toward AA production, which can promote inflammation.

Practical Feeding Considerations

  • Dogs – benefit from both plant and animal sources of fatty acids. Plant oils high in SDA, GLA, or ETA complement animal sources of EPA and DHA.

  • Cats – must receive EPA, DHA, and AA from animal sources; plant-based fatty acids like ALA and LA play a secondary role in their nutrition.

  • Balance matters – the ratio of omega-6 to omega-3 should be carefully managed, ideally between ~5:1 and 1:1, depending on the diet. Excess omega-6 relative to omega-3 promotes inflammation.

Conclusion

ALA and LA should not be dismissed simply because they convert poorly into DHA or AA. Instead, they should be valued for their direct contributions to skin, coat, immune, and anti-inflammatory health.

The key is balance:

  • Animal sources (fish oil, organ meats, eggs) provide essential preformed EPA, DHA, and AA.

  • Plant sources (hempseed, flax, chia, evening primrose, ahiflower) provide ALA, LA, SDA, and GLA, which offer their own unique benefits.

When thoughtfully combined, these fatty acids form a powerful nutritional foundation to support skin, coat, joint, hormonal, and immune health in both dogs and cats.

Research Links

Metabolism of LA in cats
https://pubmed.ncbi.nlm.nih.gov/513981/

Fatty acid metabolism in cats and dogs
https://www.scielo.br/j/rbz/a/NFGKjxhZXdwJVCfJsSCdgyr/

EPA and DHA conversion in dogs
https://www.dvm360.com/.../exploring-the-role-of-omega-3...#

Effect of high and low LA in ALA conversion
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0057463

Gamma-linoleic acid pathways
https://www.sciencedirect.com/.../gamma-linolenic-acid#

Overview of fatty acids for cats and dogs
https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.12033

Jackie Gowland