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I was recently watching a YouTube video–one of those funny cat compilations, you know the type. One of the clips included a cat being offered milk, and oh boy, did the comments go crazy. Everyone had an opinion about whether cats should drink milk or not. I’ve always heard that cats are lactose intolerant and shouldn’t have milk, but there were lots of people who disagreed. Certainly YouTube comment sections are not the place to obtain scientific information, but it sparked my curiosity. I had no idea there was so much debate about this topic, and now I wanted to find out the answer for myself.
Cats certainly seem to like milk. My parents have had two infamous ice cream thieves. And cats have been portrayed in media of all kinds happily lapping from a saucer of milk, for at least two hundred years and possibly going back to the Middle Ages, but I had some trouble verifying the dates of older images. Why do cats like milk so much, or are we imagining it?
It’s not an illusion. Dairy farmers noticed a long time ago that cats would get very excited about fresh cow’s milk. Cats are particularly fond of the cream that rises to the top of the fresh milk, as cats are naturally drawn to fatty foods that would help them survive in the wild where food is not guaranteed, and cream is certainly high in fat. It has also been demonstrated that cats relax while lapping milk (1), perhaps because it recalls pleasant maternal memories.
Unfortunately, the fact that cats like milk doesn’t mean they should drink it. Kittens drink their mother’s milk in order to gain vital nutrients and antibodies until they begin weaning. The milk of mammals contains a sugar called lactose, and infants produce an enzyme called lactase to break down this sugar which provides them with important energy for their development. As the kittens begin to eat solid food and less of their mother’s milk, they slowly stop producing lactase. The same is true of other mammals, including humans, but an unusual percentage of humans continue to produce enough lactase to digest dairy into adulthood. Cats, like other mammals, usually don’t. This means that most cats are lactose intolerant as adults.
Cats may enjoy milk or other dairy products while they’re eating them, but the majority who are lactose intolerant will pay for it later with gastrointestinal upsets. The undigested lactose can’t be absorbed into the bloodstream, so it moves straight through the intestines, drawing water with it and causing loose stools or diarrhea. They may also experience vomiting, and the action of intestinal bacteria fermenting the lactose can cause gas and bloating. Even cats that are not lactose intolerant may have dairy allergies that can also cause gastrointestinal and/or skin problems (2). Not the recipe for a happy cat, or a happy cat parent, for that matter.
Not all cats have this problem. There are some that can handle milk without an issue. Others are fine with small amounts from time to time but react negatively if given more. Regardless, it’s important to note that cow’s milk is not nutritious for cats even if they can tolerate it. It’s essentially junk food, high in calories but devoid of the protein and other nutrients that cats need. Obesity is a significant problem among pet cats. Whole milk especially poses a risk because it has so much fat. A well-nourished cat doesn’t need all that fat.
The healthiest cat treats are plain meat, cooked if you’re worried about contamination (which would be fair). Nutritious commercial treats can also be fine in moderation. However, if your cat is just crazy about milk, there are some options that are better for your cat. If you already know that your cat can tolerate lactose, then small amounts (think a teaspoon or so) of low-fat or skim milk as an occasional treat could be fine. Lower-lactose products such as plain yogurt or goat’s milk might also do. Goat’s milk has more vitamins and minerals than cow’s milk and contains the amino acid taurine, which cats require, so there’s a point in favor of the goats.
I have seen some claims that raw (unpasteurized) milk is preferable because the nutrients and enzymes present in the milk have not been heat-killed. I have also seen some information which suggests that it might be dangerous due to the presence of potentially harmful live microorganisms. Personally, I would err on the side of caution and choose pasteurized, but you can make your own decisions in the regard. Lactose-free milk products for humans are available, as well as “cat milk” products specially formulated for cats. They vary, but are generally lactose-free, low-fat, and more nutritious for cats. They are available online and at many pet stores. In any case, milk of whatever sort should be given only as a treat to adult cats, in small amounts.
Milk alternatives that should not be used include plant milks such as soy milk, almond milk, etc. Cats are carnivores and are not well-equipped to digest the carbohydrates in plants. Plant milks are often sweetened, and cats do not need all that sugar, either. Plus, it isn’t uncommon for cats to have allergies to soy.
In settling a great YouTube debate, it seems that cats should generally not drink milk, but there are cats who can handle it or other kinds of milk that cats can have. As long as it’s given as a treat, rather than used as a major part of their diet, a little dairy or an appropriate alternative can be okay. I would rather Rosie stayed out of my ice cream bowl, however.
Note: Kittens should never be given cow’s milk or any kind of alternative. They should only receive their mother’s milk or a kitten formula, if a mother isn’t available, until they are old enough for weaning.
Works Cited
- Cervantes, M., Ruelas, R., and Beyer, C. (1983). Serotonergic influences on EEG synchronization induced by milk drinking in the cat. Pharmacology Biochemistry and Behavior, 18(6), 851-55. https://doi.org/10.1016/S0091-3057(83)80004-5
- Guilford, W.G., et al. (2001). Food sensitivity in cats with chronic idiopathic gastrointestinal problems. Journal of Veterinary Internal Medicine, 15(1), 7-13. DOI: 10.1892/0891-6640(2001)015<0007:fsicwc>2.3.co;2
- Kornreich, B.G. (2020, May 2). Dear Elizabeth: Is feeding cats milk safe for your kitty? [Email newsletter] Cornell Feline Health Center.
Published on May 8, 2020
Updated January 2, 2021
