Cat Menu Leaves No Room for Dessert or a Side of Mushrooms

Cats (Felis silvestris catus), are part of the family Felidae in the order Carnivora, and that makes us obligate carnivores. This is a known and accepted scientific fact. Even so, some humans like to argue about the cat’s obligate carnivore status. When these discussions start I can’t help but yawn and curl up for a nap.

Cats are unique!

What’s good for the goose is good for the gander works because they are the same species.  What’s good for the human and perhaps even for the dog is not always  good for the cat.  We cats are unique!  The feline’s sense of taste is distinguished by a lack of attraction to compounds that taste sweet to humans, such as  sugars and high-intensity sweeteners.  This is the opposite of the attraction for sweets shown by most omnivores and herbivores and even some other carnivores such as the dog*.

Here is why:

The indifference that cats display toward sweet-tasting compounds contrasts with their

otherwise normal taste behavior toward stimuli of other taste modalities. For example, cats show
preference for selected amino acids and generally avoid stimuli that to humans taste either bitter or very sour. Congruent with these behavioral responses to taste stimuli, recordings from cat taste nerve fibers, and from units of the geniculate ganglion innervating taste cells, demonstrate responses to salty, sour and bitter stimuli as well as to amino acids and nucleotides, but do not show neural responses to sucrose and several other sugars. The senses of taste in the cat, in general, is therefore similar to that of other mammals, with the exception of an inability to taste sweet stimuli (Xia Li,2005)

Domestic cats and our wild cousins, the big cats, cannot detect sweet-tasting compounds. Sweet compounds, including sugars and artificial sweeteners, are recognized by a special taste bud receptor comprised of two genes. In cats, one of these genes is not expressed, meaning not functional. Because the sweet receptor cannot be formed, a cat cannot taste sweet things. Which came first, the inability to detect sweet leading to the cat becoming a strict carnivore or whether the evolutionary adaptations of the obligate carnivore  turned off the sweetness receptor genes because they were not needed is still under investigation.

Some humans live to eat,  but cats only eat to live.

Cats live in a different sensory world than  humans. This is super important to remember because taste is the most critical sensory system for deciding whether we are  going to eat something or pass it up. Unlike humans that have learned to think of taste as one of life’s pleasures, taste for felines is fundamental only to deciding if something is nutritionally useful or if it is dangerous. Most poisons are bitter, so that is why we can taste bitterness. But, sweetness is another story.

This might be why cats are thought to be finicky when it comes to food. Dogs, you put something in front of them and they gulp it down. Cats, need to sniff and evaluate. Some people claim their cats like sweets and I myself have been known to meow for vanilla ice cream. Not because I have a sweet tooth, but because I am in search of the protein and fat in the ice cream.

You see, cats need to eat protein that contains 10 specific amino acids they can’t make on their own. These essential amino acids are known as the building blocks for super important biologically active compounds and proteins. Amino acids are either used to synthesize proteins and other biomolecules, or oxidized as a source of energy. Deficiencies of even a single essential amino acid can lead to serious health problems.  This is why cats are on the prowl for the  amino acids in  protein.

You like mushrooms, your cat likes umami

Some cats have been known to meow for mushrooms and the reason might be  that mushrooms contain glutamic acid, a non- essential amino acid also known as glutamate and what gives the mushroom that richand savory flavor that feeds the senses and is called umami.

In 1907, a Japanese researcher named Kikunae Ikeda identified brown crystals left behind after the evaporation of a large amount of kombu broth as glutamic acid.  These crystals, when tasted, reproduced the indefinable but undeniable flavor detected in many foods. Ikeda termed this flavor umami. He later patented this method of producing a crystalline salt of glutamic acid known as monosodium glutamate, that you might also know as MSG.  Today the taste of glutamate, termed “umami” is used to elicit a unique taste quality, different from the other basic tastes of sweet, salty, sour and bitter. But to felines, umami tricks the senses and translates as amino acids duping the cat into thinking it is a  protein source and explains why your cat might meow for mushrooms.** (Kinnamon, 2009).

It is only natural to want to share with your loved ones and that is why it is tempting to share your food with your cat, but it is super important to remember that the cat is not a miniature human in a fur coat. A cat is a unique being with nutritional requirements specific to its species. What you believe to be in your best interest may not be in the cat’s best interest. If you choose to follow a vegetarian or vegan diet, please do not assume this is an appropriate diet for your feline family members too. The cat’s menu is made up almost entirely of protein sources from meat. There is no room for dessert or a side of mushrooms.

Back up:

*Even though dogs are omnivores, as they have evolved to eat vegetables and grains as well as meat, dogs are still genetically classified as carnivores.

**Because there are so many varieties of mushrooms that are poisonous, it is best to avoid feeding mushrooms of all varieties to your cat.

Kinnamon, S. C. (2009). Receptors and Transduction of Umami Taste Stimuli. International Symposium on Olfaction and Taste (pp. 55-59). New York Acedmy of Sciences.

Pickering, G. J. (2008, February 27). Optimizing the sensory characteristics and acceptance of canned cat food: use of a human taste panel. Journal of Animal Physiology and Animal Nutrition , 52-60.

Xia Li, W. L.-D. (2005). Pseudogenization of a Sweet-Receptor Gene Accounts for Cats’ Indifference toward Sugar. PLoS Genetics , 1 (1).