Flaxseed

Not always. Whole flaxseeds can pass through the gut without being digested.

Flaxseed is the seed of the flax plant, added to cat food whole or ground for fiber and plant omega-3. Tufts veterinary nutritionists note that flaxseeds are rich in alpha-linolenic acid (ALA), but that cats cannot convert ALA into the omega-3s EPA and DHA. Questions about flaxseed for a cat with a medical condition are best taken to your veterinarian.

Source: sites.tufts.edu

Flaxseed adds fiber and ALA, a plant omega-3, along with a small amount of fat energy. Tufts veterinary nutritionists say the fiber in carbohydrate sources can nourish gut bacteria and improve stool quality. The omega-3 in flaxseed is ALA, though, not the EPA and DHA found in fish oil, so it does a different job from a marine oil.

Source: sites.tufts.edu

No. Flaxseed supplies ALA, while fish oil supplies EPA and DHA directly. Tufts veterinary nutritionists say people and dogs convert ALA into EPA and DHA inefficiently, and cats cannot make the conversion at all. In a food that lists both, the EPA and DHA come from the fish oil, and the flaxseed adds ALA and fiber.

Source: sites.tufts.edu

Yes. Flaxseed and linseed are two names for the seed of the same plant, Linum usitatissimum. In the United States, flaxseed is the usual word on food and pet food labels. Linseed is more common in British English and in industrial uses, such as linseed oil for wood finishing. On a cat food label, both names point to the same seed.

Flaxseed gets 3 out of 5 from Pettings, which files it as a general cat food ingredient. It shows up on 52 of the 149 dry cat foods we list. Each food's page shows how the whole recipe scores, so one ingredient score is only part of the picture.