Cats Cannot Get Vitamin A From Carrots

Beta-carotene is a yel­low pig­ment that is found in many yel­low, orange, and dark-green veg­eta­bles. For human beings and many oth­er mam­mals, beta-carotene is a provi­t­a­min of vit­a­min A. This means that beta-carotene does not have vit­a­min A effects until the body con­verts it to retinol. Human beings can con­vert beta-carotene to retinol. Thus, human beings can get vit­a­min A from the beta-carotene in fruits and veg­eta­bles. In con­trast, cats can­not con­vert beta-carotene to retinol. Retinol is found only in meat and oth­er ani­mal prod­ucts, such as egg yolk. For this rea­son, cats can­not sur­vive on a pure­ly plant-based diet. If you want to make a pure­ly plant-based (veg­an) cat food, you must add the nutri­ents, such as retinol, that nor­mal­ly come only from ani­mal sources.

Cats must get their vit­a­min A in the form of retinol or relat­ed com­pounds (such as retinyl palmi­tate). In con­trast, it is bet­ter for human beings to get their vit­a­min A in the form of beta-carotene. The human body con­verts beta-carotene to retinol on an as-need­ed basis. If you eat a huge amount of the fruits and veg­eta­bles that con­tain beta-carotene, some of the extra beta-carotene might build up in your skin. As a result, you will get a healthy gold­en glow that is more attrac­tive than a sun­tan. In con­trast, if you over­dose on retinol, either from tak­ing sup­ple­ments or from eat­ing polar bear liv­er, you will get a poten­tial­ly fatal swelling of the brain. This con­di­tion is called pseudo­tu­mor cere­bri (which lit­er­al­ly means fake tumor of the brain). If the brain swelling dam­ages the nerves that con­nect the eyes to the brain, the result can be per­ma­nent blind­ness.

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 the vit­a­mins in pill form. In fact, the vit­a­min pills might actu­al­ly increase the risk of 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 pills con­tain­ing beta-carotene and retinol (in the form of retinyl palmi­tate) could reduce the risk of can­cer in peo­ple who were at high risk for lung can­cer. The study was stopped ear­ly because the can­cer rate turned out to be high­er in the peo­ple who got the vit­a­min A pills than in peo­ple who got a place­bo.

Pho­to by mattbuck4950