All About Vitamin A for Cats

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Vitamin A is an essential vitamin for cats. This means that they need vitamin A for their bodies to work properly. Most animals can make vitamin A in the body from base nutrients found in foods like leafy plants and vegetables. But it won’t surprise you to know that cats are a bit different! They can’t make their own vitamin A, so they must eat pre-made vitamin A in their diets. The best sources of this are meat (especially liver) and oily fish. This is one of the reasons why it is not safe for cats, unlike dogs, to eat a vegetarian or vegan diet.

This article will explain why vitamin A is essential for your cat’s health and how to ensure your cat is getting all they need. It will also look at what happens if your cat ingests too much (vitamin A poisoning) or too little (vitamin A deficiency).

About Vitamin A for Cats

Vitamin A, also known as retinol, is mostly stored in the liver. It is an essential vitamin for animals—including cats, dogs, and humans.

Sources of Vitamin A

Vitamin A can be found in food in two main forms: pre-made vitamin A (retinoids) and precursors (carotenoids).

The best source of pre-made vitamin A is animal meats, particularly liver and oily fish. It is also found in egg yolks and some dairy products.

Most animals can use vitamin A precursors called carotenoids to form vitamin A within their bodies. These are found in vegetables like carrots, spinach, sweet potatoes, and peppers, as well as some fruits.

Why Is Vitamin A Essential for Cats?

Cats are obligate carnivores, meaning they must eat meat in their diet. TheCats / Shutterstock.com

Unlike dogs and humans, cats are obligate carnivores, meaning they must eat meat to stay healthy. Other animals have an enzyme that can use vitamin A precursors found in fruit and vegetables to produce vitamin A within their bodies. In cats, this enzyme doesn’t work very well, meaning they must eat the pre-made vitamin A found in meats and oily fish. This is why it isn’t safe for cats to eat vegetarian or vegan diets.

Vitamin A plays many important roles in your cat’s body:

• Vision: It’s long been known that vitamin A is needed for normal vision, especially helping your cat to see well in low light levels. This is where the saying “carrots help you see in the dark” comes from! Unfortunately, the enzyme that converts carotenoids in carrots to vitamin A doesn’t work as well in cats, so carrots aren’t a good source for them.
• Healthy skin and coat: Vitamin A helps your cat’s skin, mucous membranes, and coat stay shiny and strong.
• Immune function: Vitamin A plays a crucial role in the development of your cat’s immune system, helping them fight off illness and infection. It promotes the growth and activity of important immune cells and is known to have anti-inflammatory and antioxidant benefits.
• Growth and development: Kittens require high levels of vitamin A in colostrum and their mother’s milk for normal growth and development. Once your cat is fully grown, they don’t need such high levels. However, it is still important for supporting normal cell growth and reproduction in adult cats.

How Can I Ensure My Cat Is Getting Enough Vitamin A?

Now you know why vitamin A is so important for your cat, you’ll want to know how you can be sure they’re getting enough. The good news is that, nowadays, commercially available cat foods have been formulated to ensure that they contain the right balance of essential nutrients, including vitamin A.

Dietary Requirements

The recommended nutritional requirements for cats have been established by the Association of American Feed Control Officials (AAFCO), who work alongside the United States Food and Drug Administration (FDA). When choosing a food for your cat, look for an AAFCO approval on the label—this means that it is nutritionally complete and balanced for that life stage.

The AAFCO guidelines ^[1] state that the minimum amount of vitamin A required in an adult cat’s diet is 3,332 IU per kilogram of food when measured in dry matter, with a maximum amount of 333,300 IU.

Vitamin A Supplements

If you feed your cat a complete, balanced diet, there is no need to supplement their diet with extra vitamins. However, if your cat is eating a home-cooked diet or a commercial diet that is not nutritionally complete, they may need to take vitamins or other nutritional supplements.

Always talk to your veterinarian before adding anything extra to your cat’s diet. Too much, as well as too little, of a vitamin can harm your cat’s health. Your veterinarian can ascertain whether your cat needs any supplements and recommend safe and proven products.

Vitamin A Deficiency in Cats

Thankfully, since the development of commercially available complete pet foods, vitamin deficiencies in cats have been rare. But with the rise of home-cooked diets and an interest in vegetarian (and even vegan) diets, as a veterinarian, I have noticed conditions like vitamin A deficiency are on the rise.

Although vitamin A deficiency usually occurs in cats fed an inappropriate diet, cats with nutrient absorption problems (for instance, inflammatory bowel disease) can also suffer from vitamin deficiencies.

If your cat is suffering from vitamin A deficiency, you may notice symptoms such as:

• Dull coat and skin
• Night blindness
• Eye problems, including:
  • Dry eyes
  • Conjunctivitis
  • Corneal ulcers
  • Retinal degeneration
  • Light sensitivity (photophobia)
  • Keratitis
• Prone to infections and illness

Vitamin A deficiency is even more serious in pregnant queens, as it is vital for the normal development of kittens. If a pregnant cat has low vitamin A, it can cause stillbirth or serious congenital problems in her kittens.

Treating Vitamin A Deficiency

Your veterinarian will usually suspect vitamin A deficiency by the cat’s symptoms and through discussing your cat’s diet. The recommended treatment is simply to increase the amount of vitamin A your cat is eating. This may simply mean swapping them to a complete, balanced diet. Your veterinarian may also recommend adding a vitamin A supplement or a food rich in vitamin A (such as liver) until their symptoms have resolved.

To avoid the risk of vitamin A poisoning, supplement vitamin A only under the guidance of your veterinarian.

Vitamin A Poisoning in Cats

In cats fed a complete, balanced diet, there is no need to give them any extra vitamins or supplements. New Africa / Shutterstock.com

As the safe dose range for vitamin A is so wide (over a thousand times the recommended dietary minimum in cat food), vitamin A toxicity is rare in cats fed a complete commercial diet. However, it can occur in cats fed large amounts of liver, which is very rich in vitamin A. It can also happen if cats are given excessive amounts of multivitamins or fish oil over time.

If very large doses of vitamin A are ingested at once, such as through a curious kitty getting into a pack of multivitamins, cats can become unwell very quickly. Signs might include vomiting, lethargy, and peeling of the skin. However, acute cases of vitamin A poisoning are much rarer than those caused by chronic over-ingestion over weeks to months.

Symptoms of chronic vitamin A poisoning in cats include:

• Anorexia (not eating)
• Weight loss
• Stiffness and muscle pain
• Muscle weakness
• Lameness
• New bone formation (especially around the neck, spine, chest, and joints)
• Neurological signs

If a pregnant cat is fed too much vitamin A, it can cause significant birth abnormalities in her kittens. These range from cleft palates to problems with their bones and teeth. So, always ensure your pregnant cat is fed an appropriate diet.

Treating Vitamin A Poisoning in Cats

If your cat has eaten a sudden, large amount of vitamin A, your veterinarian will recommend making them sick. This must occur within a few hours of ingestion – so always contact your veterinarian immediately if you think your cat may have eaten something they shouldn’t.

However, it is much more common for vitamin A toxicity to happen slowly, over weeks to months. Your veterinarian will probably suspect it after simply discussing your cat’s diet. They might recommend taking a blood sample to assess your cat’s overall health and organ function. In severe cases, they may also recommend x-rays to look for bony growth, which might be causing your cat pain.

The good news is cats suffering from long-term vitamin A poisoning respond well to reducing the levels in their diet. This usually involves stopping feeding liver, fish oil, or vitamin supplements and ensuring they are on a complete, balanced diet. Many of your cat’s symptoms should resolve after a few weeks. Unfortunately, if your cat has developed bony growths, these won’t be reversible, but the effects can be managed with good pain relief.

Drug Dosing Disclaimer: We can only provide doses for medications that are FDA-approved for use in cats and only as the label guidelines dictate. For medications that are used off-label, we can only provide guidelines and safety information. Safe and appropriate dosing for off-label medications can only be determined by a primary care veterinarian.

We encourage you to work with your veterinarian to determine if a particular medication is appropriate for your cat. Changing or adjusting a dose for your cat on your own without consulting with a veterinarian can carry risk. We do not encourage the use of medications prescribed for human use in pets without first consulting with a primary care veterinarian.