Histidine Amino Acid & Symptoms of Deficiency

Histidine is one of the essential amino acids recognized by AAFCO and pet food manufacturers are required to formulate a pet diet that includes Histidine. There are reasons for this recognition as essential amino acid and in this article, I’ll explain the benefits, sources, and deficiency symptoms for dogs and cats.

Why we evaluate protein sources of pet food by amino acid composition:

To be objective in our ranking of various dog and cat food recipes, we evaluate them based on their amino acid composition. In other words, we’re not looking at the “protein sources” as a whole (e.g. chicken, beef, lamb, etc.), but rather we’re looking at the individual amino acids that make up those proteins.

This is important because it’s the amino acids that are actually used by the body to build muscle, repair tissue, and perform all the other functions that require protein.

Let’s define amino acid better;

Amino acids are the building blocks of proteins and there are 20 different amino acids that can be combined to form a protein. Of these 20, 9 are essential for dogs and 11 are essential for cats. This means that the pet’s body cannot produce these amino acids and they must be obtained through the diet.

What is Histidine and where does it come from?

Histidine is an α-amino acid that is used in the biosynthesis of proteins. It contains a histamine group that is responsible for many of its biochemical activities. Dogs and cats can synthesize Histidine from other amino acids, but they still require dietary sources to meet their needs.

Histidine is required for the proper growth and development of all cells and tissue. It also plays an important role in the repair of damaged tissue. Histidine is also required for the production of hemoglobin, which carries oxygen in the blood.

Histidine is found in animal proteins such as meat, fish, and poultry. It’s also found in egg whites and dairy products. Plant-based sources of Histidine are not as well absorbed as animal-based sources.

Sources of Histidine

Dietary sources of histidine for pets include meat, poultry, fish, and eggs. Histidine is also found in some plant-based proteins such as beans and rice.

Chicken, turkey, fish, eggs, and tuna are the main sources of histidine and other protein sources such as beef, lamb, pork, herring lack histidine.

The table below shows 9 protein sources and the three that contain histidine.

Image showing protein sources with and without arginineImage showing protein sources with and without arginine

How much histidine for dogs:

Following NRC recommendation to include Histidine as an essential amino acid, AAFCO has been recommending it as an essential amino acid since 2006.

For dogs, histidine are required in smaller quantities compared to arginine. In fact, only tryptophan and methionine match histidine in terms of small quanties recommended by AAFCO.

For growing dogs or puppies, AAFCO recommends 0.44% and 0.19% for adult dogs.

How much histidine for dogs:

Studies have shown histidine to prevent cat health issues such as cataracts.

AAFCO recommends giving kittens a minimum of 0.33% of histidine on dry matter basis and 0.31% to adult cats.

Benefits of Histidine for dogs and cats

Benefits of histidine for dogs include promoting healthy skin and coat, helping to heal wounds, and reducing inflammation. Histidine can also help to boost the immune system.

Histidine plays an important role in many biochemical reactions in the body, including:

– Acting as a precursor for histamine (involved in immune responses and gut function)

– Serving as a methyl donor (involved in DNA and RNA synthesis)

– Acting as an antioxidant (reducing inflammation and cell damage)

Benefits for cats are similar but also include reducing hairballs and promoting healthy digestion.

Histidine Deficiency symptoms in dogs and cats

A histidine deficiency can cause a number of health problems in dogs and cats, including:

– Anemia

– Slow growth

– Skin problems

– Muscle weakness

– Behavioral changes

If you think your pet may be deficient in histidine, please consult your veterinarian.

Supplementing with Histidine:

If you are feeding your pet a complete and balanced diet, there is no need to supplement with histidine. However, if your pet has a histidine deficiency, your veterinarian may recommend a histidine supplement.


Histidine is an essential amino acid for dogs and cats. It’s important for growth, development, and repair of tissues. Histidine can also help to boost the immune system and reduce inflammation. Dietary sources of histidine include meat, poultry, fish, and eggs.


  • Quam, Darcy & Morris, James & Rogers, Quinton. (1987). Histidine requirement of kittens for growth, haematopoiesis and prevention of cataracts. The British journal of nutrition. 58. 521-32. 10.1079/BJN19870120.