Why Vegan Cats need Seaweed – Or – Why Arachidonic Acid is so Important

You have probably heard of Essential Fatty Acids, or EFAs – omega-3’s and omega-6’s. There is one particular omega-6 that’s critical for health of cats and dogs – Arachidonic Acid – and most plants don’t have it.

Arachidonic Acid (AA for short) is an essential component of cell membranes in mammals and it plays an important role in cell signaling and inflammation, and is abundant in the brain, muscles and liver. Like other types of omega-6 fatty acids, AA also contributes to maintenance of healthy skin and coat, reproductive system, and overall energy level. Lack of AA in cats leads to, among other things, poor reproductive performances and improper blood clotting (Biourge, 2001).

Cats cannot make AA, while dogs can. So in this blog post we will focus on cats, since they cannot synthesize their own AA. Cats require a dietary source of AA, especially during the demanding life stages of growth, gestation and lactation.

AA is found in abundant supply in animal tissues, especially organs. Plants, on the other hand, offer limited quantities of AA. So where does this leave cat guardians who wish their cats to stay off of animal tissue and organs?

Seaweed is a good source of Arachidonic Acid

Seaweed – and especially kelp – is the main source of AA in plant-based formulas for companion animals. Many veterinarians and scientists regard seaweed as an extremely healthy addition to our pets' diets.

You might be surprised to discover that seaweed has a very long history of being included in animal food. Early animal caretakers observed that feeding their animals seaweed resulted in advantages such as improved coat shine, greater resistance to infection, as well as increased reproduction in farmed animals.

Nowadays, scientists understand why seaweed is so healthy for animals (as well as humans). It turns out that seaweeds are a rich source of minerals (it contains 10 to 20 times the concentration of minerals found in land plants), in a form that is more easily absorbed. Additionally, seaweeds are a source of omega 3 and omega 6 fatty acids, including arachidonic acid (an omega 6 fatty acid that is essential for cats) and α-linolenic acid (an omega 3 fatty acid required by dogs).

Most recently, seaweeds have been found to be an excellent source of prebiotics, which have been found to help promote growth of many of the good bacteria while at the same time inhibiting growth of certain pathogenic bacteria. The presence of prebiotics is one of the reasons seaweed is thought to help keep animals healthier and more resistant to infection.

Arachidonic Acid in plant-based pet food

Many plant-based formulas use kelp, spirulina or other kinds of seaweed to provide AA (see chart below).

*Ami confirmed that AA is added to Ami Cat food, and explained that the label is shown as per EU regulations.

In cases where we didn’t find kelp/spirulina/seaweed explicitly stated in the list of ingredients, as a precaution, we recommend adding Green Mush™ and VegeYeast. GreenMush is a supplement containing AA, whereas VegeYeast helps maintaining the acidic balance (see section on Maintaining Acidic Balance below).

To supply AA to an adult cat add 4 g of Green Mush™ per day (1 rounded teaspoon or basically two level teaspoons) to meet the National Research Council (NRC) recommended amount.

To maintain acidity (and for a nice cheesy flavour), add 15 g of VegeYeast per day.

Maintaining Acidic Balance

Green superfoods like Green Mush, chlorella, and kelp are alkaline forming (Bass, 2019). Cats should maintain an acid urine pH between 6.0 and 6.5. Using VegeYeast in your cat’s meals will counter the alkalinity of your chosen AA source. Few cats will need additional acidity in the diet. If your cat needs a lower urine pH, vitamin C (ascorbic acid) can be added. The recommendation is often 500mg of vitamin C per day to acidify urine. Your vet can advise further. You can test urine pH at home or at a vet’s office. It is ideal to test urine pH before changing the diet and about 3-weeks after adding a new alkaline or acid forming ingredient to food. Only infrequent testing is needed after the initial transition.

To Summarize

Arachidonic Acid is critical for maintaining good health in cats on a vegan diet. Dogs can synthesize AA, while cats cannot. Most plants don’t have AA, but seaweeds do. Best source of AA for a vegan cat diet is kelp, spirulina, chlorella manna, or other seaweeds. To be on a safe side, add 4g of GreenMush daily to a vegan diet to ensure ample supply of AA, although most commercially available vegan cat foods are already supplemented with kelp. Watch the acidic (pH) balance of your cat's urine, and add VegeYeast, about 15g per day to ensure acidity of 6.0 - 6.5.


  1. Biourge, V. (2001). Feline Nutrition Update - VIN. [online] Vin.com. Available at: https://www.vin.com/apputil/content/defaultadv1.aspx?id=3843764&pid=8708&print=1 [Accessed 23 Feb. 2020].
  2. Bass, A. (2019). Arachidonic Acid. [online] Compassion Circle. Available at: https://compassioncircle.com/vegan-pets/arachidonic-acid/ [Accessed 23 Feb. 2020].

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