Vitamin A for Cats

Vitamin A is one of over 40 essential nutrients for cats, making it crucial to their well-being. Vitamin A aids with vision and growth while supporting muscle health, skin health, and the immune system. It also helps protect against certain forms of cancer. All pet foods considered "complete and balanced" by the Association of American Feed Control Officials (AAFCO) should contain set minimum amounts of vitamin A. 

Vitamin A is fat-soluble and stored in the liver. It mainly takes two forms: carotenoids from red, yellow, and orange produce or retinoids in meat and animal byproducts. 

So, how much vitamin A do cats need in their diet? And what are the health effects of too much or too little vitamin A in cats? Scroll down to learn more about vitamin A for cats.

Vitamin A is critical for night vision in cats. It helps cats form the macular pigments needed to see in low light. Night vision isn't possible for cats without vitamin A, and one common early sign of a vitamin A deficiency in cats is night blindness. 

Vitamin A's importance to growth and development begins in utero. Some studies suggest vitamin A plays a significant role in early development, with retinoids from vitamin A promoting healthy limb development. 

Kitten foods contain vitamin A supplements, as kittens haven't developed the capacity to store vitamin A in their livers. Vitamin A isn't as important for adults as kittens, but vitamin A-deficient cats may develop reproductive issues. Skin and coat health is also affected by vitamin A.

Vitamin A is vital to a cat's immune system. It helps the circulation of white blood cells, helping to fight off bacteria and viruses.

According to the AAFCO nutrient profiles, kittens and pregnant or nursing cats require a minimum of 6,668 IU per kilogram of food on a dry matter basis. 

Adult cats require a minimum of 3,332 IU per kilogram of food on a dry matter basis. Cats shouldn't ingest more than 333,300 IU of vitamin A per kilogram of food as dry matter.

Unlike dogs, cats cannot convert beta-carotene because they're obligate carnivores and lack certain intestinal enzymes. Cats require a preformed retinoid vitamin A source. As a result, fruit and vegetables aren't a primary source of vitamin A for cats. 

Primary sources of preformed vitamin A for cats include:

• Meat, especially liver
• Fish oil
• Egg yolk
• Supplements
• Synthetic vitamin A

Due to an inability to process beta-carotene, cats are more prone to vitamin A deficiencies (hypovitaminosis A) than dogs. Ocular symptoms of a vitamin A deficiency are similar in dogs and cats, but other clinical signs differ. 

Hypovitaminosis A in cats can be severe, especially in breeding cats. Vitamin A deficiencies can cause stillbirths and congenital defects, such as blindness, ataxia, hairlessness, hydrocephalus, and cerebellar dysplasia. A change in cell formation in the tissue lining of certain organs, called squamous metaplasia, can also be due to hypovitaminosis A. 

Most signs of a vitamin A deficiency in cats affect the eyes and include:

• Night blindness
• Eye dryness
• Conjunctivitis
• Keratitis
• Photophobia
• Corneal ulceration
• Retinal degeneration

Treatment of vitamin A deficiency

The primary method of curing a vitamin A deficiency in cats is to adjust their food intake. Your vet may prescribe your cat a food that's high in vitamin A or a vitamin A supplement. 

Alternatively, your vet may recommend adding food high in vitamin A to your cat's diet. Liver is the most common food recommendation due to its retinoid levels. 

Malabsorption can cause hypovitaminosis A, making it harder to treat as there can be several underlying causes, such as inflammation, bacterial infections, and even cancer. Inform your doctor of any and all symptoms your cat is experiencing so they can make a quicker diagnosis.

Hypervitaminosis A, or vitamin A toxicity, is more common in cats than dogs, as cats are generally more sensitive to elevated vitamin A levels. Hypervitaminosis A is most common in kittens when fed a diet primarily of liver. Generally, Hypervitaminosis A is rare among kittens and adult cats.

There are a wide variety of signs of vitamin A toxicity in cats, some of which can cause serious health issues. Signs of vitamin A toxicity include:

• Lameness
• Lethargy
• Difficulty grooming
• Joint stiffness
• Skeletal malformations
• Internal hemorrhaging 
• Weakened bones causing fractures
• Osteoporosis

For more information, check out our guide on vitamin A poisoning in cats.

Treatment of vitamin A overdose

As with a vitamin A deficiency, toxicity is usually treated by a change to a cat's diet. If your vet suspects a vitamin A overdose, they may order blood tests and biochemistry to test the condition of your cat's liver. 

Your vet may prescribe or recommend a cat food that contains the minimum suggested vitamin A dose. Alternatively, they might recommend you stop giving your cat certain supplements or feeding them a liver-rich diet. 

Unfortunately, any changes to your cat's bone and body condition may be irreversible. Your vet may prescribe anti-inflammatory medication and painkillers if your cat is in pain or discomfort.

You don't usually have to give a cat vitamin A supplements. Cats fed a "complete and balanced " cat food will get all the necessary vitamin A from their diet. 

The only time you're likely to need to give your cat a vitamin A supplement is if they're prone to deficiency due to an underlying condition. 

Kittens and pregnant cats may benefit from vitamin A supplements. Kittens can't yet build up vitamin A reserves in the liver and require more vitamin A for growth. Pregnant cats may need a vitamin A supplement to help their kittens develop. 

Certain health conditions, including malabsorption caused by specific genetic mutations, can affect vitamin A intake. Certain medical conditions, such as liver disease, can also affect a cat's vitamin A levels. 

Never give your cat a vitamin A supplement intended for humans. Always consult a vet before giving your cat a vitamin A supplement. 

Overall, vitamin A is an essential nutrient for cats. It aids in early development, promotes immunity, and ensures healthy eyesight. Cats need to get vitamin A from retinoids in meat and animal byproducts, as they cannot convert beta-carotenoids like dogs. 

Both vitamin A deficiency and toxicity are possible in cats and can cause a range of clinical signs, ranging from ocular issues to skeletal abnormalities.