Are cats Lactose Intolerant?  We visualize a cat drinking from a saucer of milk, contently walking away to lay in the sun but is this really good for them?  Experts tell what Lactose means and how it affects kittens into adulthood.  According to the vets at Chewy and Hills Science Diet, feeding an adult cat milk can cause digestive upset, diarrhea, and dehydration.

What is lactose?

Milk contains a carbohydrate called lactose, which is a disaccharide sugar made up of galactose and glucose that’s found in all types of milk. But the lactose doesn’t always agree with an adult cat’s digestive system. “Lactose is a natural sugar found in mammals’ milk, including cats. Kittens will typically drink their mother’s milk until they are at least four weeks old,” explains Dr. Jesus Aramendi, senior veterinarian at Chewy. “In order to be able to break down this carbohydrate to its most simplest form, mammals’ bodies need to produce the enzyme lactase.”

Baby mammals, like kittens, produce enough lactase that they can digest their mother’s milk. But as they wean off of their mother’s milk—at four to six weeks of age, on average—and grow into adulthood, they begin to produce less lactase and lose the ability to properly digest milk. As a result, they could get an upset stomach or other symptoms like diarrhea after drinking milk. “Just like humans, cats can be lactose intolerant, and most adult cats may be,” says Dr. Aramendi.

Lactose intolerance can be mild to severe. If your cat is experiencing vomiting and diarrhea, it can lead to dehydration. An upset stomach can also be painful from gas and fluid gurgling around in the intestinal tract. Giving your cat some milk as a treat could cause them physical distress if they are lactose intolerant.

What happens when cats drink milk?

“When a cat drinks milk undigested lactose will stay in their intestines rather than passing into the bloodstream, and end up fermenting,” says Dr. Richter. “Whole, 2 percent, and skim cow’s milk can also add unhealthy amounts of fat to your cat’s diet.” Since cats don’t have the enzyme necessary for digesting lactose, drinking milk can lead to gastrointestinal issues such as an upset stomach, diarrhea, vomiting, loss of appetite and weight, abdominal pain and discomfort, and cause behavior changes such as increased scratching.

What should cats be drinking instead of milk?

Cats need plenty of water,” Leasa Greer, the Manager of Nutrition & Regulatory Affairs at Solid Gold Pet, told Reader’s Digest. “Water is incredibly important for promoting optimal organ function in cats. A great way to make sure your cat is getting enough water is by feeding him/her wet canned food. Cats are generally less keen on drinking water, so wet food is great for keeping cats hydrated.” Now that you know the answer to the question of, “Can cats drink milk,” is “no,” make sure you avoid making these other dangerous mistakes that cat owners make.

To provide your cat with everything they need, a complete cat food designed to meet all of their nutritional needs, such as Hills Science Plan, is the best option to keep your cat healthy and happy. Even special cat milk does not provide all of the nutrients that a high quality complete cat food does, so apart from maybe a very occasional treat, it is best to cut out the milk and stick to the scientifically proven food in order to promote the best cat health possible.

Interested in reading more about cats and kittens?  Check out my previous posts here: