By Dial A Vet Veterinary Team
Linseed is marketed to people as a source of omega-3, so it is natural to wonder whether a sprinkle would help a cat with dry skin or a dull coat. Flaxseed is not toxic to cats. The problem is that cats are particularly poor at using the type of omega-3 flax contains. In a cat, flax mostly adds fibre and calories, and it can upset a sensitive stomach.
Key takeaways
- Flaxseed (linseed) is not toxic to cats.
- Its omega-3 is ALA, a plant form. Cats convert very little of it into the EPA and DHA they can actually use.
- Cats need animal-derived fats, including arachidonic acid, which flax does not provide.
- Flax can cause loose stools, wind or vomiting, particularly if a cat eats a lot.
- Skin, coat, joint or kidney concerns need a vet assessment rather than a pantry fix.
- Related: flaxseed for dogs, chia seeds and cats, sesame seeds and cats.
Cats and plant fats
Every species turns dietary fats into the longer-chain forms the body uses for skin, brain, eyes and immune function. Cats have very low activity of one of the key enzymes involved, called delta-6 desaturase. In practice that means:
- They cannot make enough arachidonic acid from plant oils, so they need it ready-made from animal fat.
- They convert only a tiny fraction of ALA from flax into EPA and DHA.
This is part of what makes cats obligate carnivores. It is also why the omega-3 products vets sometimes recommend for cats come from marine sources rather than seeds. Flax looks good on a label for people, but much of its value is lost in a cat.
Is any flax okay?
Many commercial cat foods include a small amount of linseed or flaxseed oil as part of a balanced formula. That is fine. The amounts are controlled and the rest of the diet is designed around it.
Adding extra at home is a different matter. A cat licking a few seeds from your breakfast bowl will come to no harm. Regularly sprinkling ground flax on your cat's food has little upside and some downside: it adds calories to a small animal, can soften stools, and may displace meat-based food a picky cat would otherwise eat.
Possible problems
- Digestive upset. The gel-forming fibre can cause wind, soft stools or vomiting, especially in larger amounts.
- Whole seeds are often vomited back or passed unchanged.
- Rancid flax smells bitter or fishy and can make a cat ill. Ground flax spoils quickly at room temperature.
- Weight gain. Flax is around 40 percent fat by weight, and a cat's daily calorie needs are small.
- Hardware linseed oil, used on timber, is not food and may contain driers and solvents. If your cat licks a freshly oiled surface or chews a soaked rag, call your vet.
If your cat has skin or coat problems
Dry, flaky or greasy skin, a dull coat and overgrooming in cats have many possible causes: fleas, allergies, mites, ringworm, pain that stops grooming, thyroid disease, kidney disease, or a diet that is not complete and balanced. A bowl of linseed will not address any of these. A vet check can, and if a fatty acid supplement is part of the plan, your vet can recommend a product and amount suited to your cat.
What to do if your cat ate flaxseed
- Work out how much and in what form: seeds, ground meal, food oil or hardware oil.
- A few seeds or a lick of meal: no action needed. Watch for vomiting or loose stools.
- A larger amount: offer water and keep an eye on appetite and the litter tray for a day or two.
- Hardware linseed oil or a solvent-based product: call your vet or the Animal Poisons Helpline on 1300 869 738.
- Do not try to make your cat vomit at home.
When it is an emergency
Seek urgent care if your cat vomits repeatedly, refuses food for more than 24 hours, has a painful belly, drools heavily, breathes with effort, or seems weak or wobbly. Any cat straining in the litter tray with little result should be seen urgently, since it can be a urinary blockage.
FAQ
Is flaxseed oil good for cats?
Cats use plant omega-3 poorly. If your vet thinks omega-3s would help, they are likely to suggest a marine-based product made for pets.
Can flaxseed help my cat's constipation?
Constipation in cats often has an underlying cause, such as dehydration or kidney disease. Talk to your vet before adding fibre.
Are golden and brown flax different for cats?
Not in any meaningful way. Neither offers much to a cat.
My cat's food lists linseed. Should I worry?
No. Small amounts in a balanced commercial food are normal and safe.
Talk with a vet
If your cat's coat, skin or stools have changed, a Dial A Vet veterinarian can talk through what you are seeing and help you decide on next steps. Book a Dial A Vet consult.
References
- Bauer JE. Metabolic basis for the essential nature of fatty acids and the unique dietary fatty acid requirements of cats. Journal of the American Veterinary Medical Association. 2006;229(11):1729-1732.
- Merck Veterinary Manual. Nutritional requirements of small animals.
- National Research Council. Nutrient Requirements of Dogs and Cats. Washington DC: National Academies Press; 2006.
- Cornell Feline Health Center. Feeding your cat.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.