Cats Cannot Get Vitamin A From Carrots

Human beings can get vit­a­min A from eat­ing veg­eta­bles. Many veg­eta­bles con­tain beta-carotene. Our body can con­vert beta-carotene to the active form of vit­a­min A. In con­trast, cats need to get the active form of vit­a­min A from their food. This form of vit­a­min A is found only in ani­mals, not in plants.

What Is Beta-Carotene?

Many fruits and veg­eta­bles are bright yel­low, orange, or red. These col­ors come from pig­ments called carotenoids. One exam­ple is beta-carotene. Carotenoids do sev­er­al impor­tant things in the plant. They help to col­lect light, which is used in pho­to­syn­the­sis. They also act as antiox­i­dants. Antiox­i­dants help to pro­tect the plant against some of the dan­ger­ous by-prod­ucts of pho­to­syn­the­sis.

Human beings and many oth­er mam­mals can con­vert beta-carotene to retinol. Retinol is the active form of vit­a­min A. Thus, human beings can eas­i­ly get their vit­a­min A from eat­ing veg­eta­bles. A cat can­not.

Cats Need Retinol

A cat can­not con­vert beta-carotene to retinol. Retinol is found only in meat and oth­er ani­mal prod­ucts, such as egg yolk. Thus, cats can­not sur­vive on a pure­ly plant-based diet. That is why cats are called oblig­ate car­ni­vores. To make a veg­an cat food, you must add the nutri­ents, such as retinol, that nor­mal­ly come only from ani­mal sources.

Cats Don’t Need Vitamin C

Even if a cat eats no fresh fruit or veg­eta­bles, it will nev­er get scurvy. All plants and most ani­mals can make their own sup­ply of ascor­bic acid. Human beings and guinea pigs can­not. If we don’t get ascor­bic acid (vit­a­min C) from our food, we will die of scurvy.

Human Beings Should Eat Vegetables

Cats must get their vit­a­min A in the form of retinol or relat­ed com­pounds (such as retinyl palmi­tate). In con­trast, human beings should get their vit­a­min A in the form of beta-carotene.

Your body has ways to lim­it the amount of beta-carotene it absorbs from your food. If you eat a lot of fruits and veg­eta­bles, a lit­tle bit of extra beta-carotene might build up in your skin. The result is a healthy gold­en glow that is more attrac­tive than a sun­tan. Your body will con­vert beta-carotene to retinol only on an as-need­ed basis. Thus, you can­not get a vit­a­min A over­dose from eat­ing too many car­rots.

Even if you binge on car­rot juice, you will mere­ly turn yel­low. But if you over­dose on retinols, you might go blind or even die. An over­dose of retinols can cause a dan­ger­ous swelling of the brain. Doc­tors call this con­di­tion pseudo­tu­mor cere­bri (fake tumor of the brain).  This swelling can destroy the nerves that lead from the eye to the brain. Pseudo­tu­mor cere­bri has hap­pened to peo­ple who over­dosed on vit­a­min A sup­ple­ments. It has also hap­pened to peo­ple who ate polar bear liv­er.

Food, Not Pills!

Human beings should get their vit­a­min A in the form of beta-carotene. And they should get their beta-carotene from fruits and veg­eta­bles, rather than from pills. Peo­ple who eat a lot of fruits and veg­eta­bles tend to have bet­ter health, includ­ing low­er rates of can­cer. You can­not get the same effect by tak­ing vit­a­min pills. In fact, the vit­a­min pills might actu­al­ly increase the risk of can­cer.

Beta-Carotene, Vitamin A, and Lung Cancer

In the 1980s, the Nation­al Can­cer Insti­tute launched a major study called the Carotene and Retinol Effi­ca­cy Tri­al (CARET). The pur­pose of the study was to see whether beta-carotene sup­ple­ments would pro­tect peo­ple against lung can­cer. The study recruit­ed cig­a­rette smok­ers and peo­ple with asbestos in their lungs. These peo­ple were giv­en either a vit­a­min pill or a place­bo. The vit­a­min pill con­tained beta-carotene and retinol (in the form of retinyl palmi­tate). The study was stopped ear­ly for safe­ty rea­sons. The pills increased the risk of get­ting lung can­cer.

Pho­to by mattbuck4950

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