Why Most Cats Are Lactose Intolerant

It’s a common image—cats lapping up a bowl of milk—but is it safe for them? Despite popular belief, most cats are actually lactose intolerant, meaning their bodies can’t properly digest lactose, the sugar found in milk. Feeding your cat dairy products like milk or cheese can lead to digestive issues, including stomach upset, diarrhea, and discomfort. In this guide, we’ll explore why cats are lactose intolerant, the symptoms to watch for, and what alternatives you can offer your feline friend instead of dairy.

Why Do Cats Become Lactose Intolerant?

The main reason cats develop lactose intolerance is that the activity of the enzyme lactase is greatly reduced in adult cats. Lactase is a digestive enzyme responsible for breaking down lactose, a sugar found in mammalian milk. During a cat's juvenile years, the body produces higher amounts of lactase to accommodate the digestion of lactose in breast milk. However, as the cat grows, especially after weaning, the body's production of lactase decreases significantly, making it difficult for adult cats to digest the lactose in milk, which can lead to lactose intolerance . 

In addition, the composition of cat milk is different from that of cow's milk in that the protein and fat molecules in cat milk are smaller and more suitable for digestion and absorption by kittens. Cow's milk, on the other hand, has a relatively high lactose content and a long fat chain that is not easily digested by adult cats, which is one of the reasons why adult cats are more prone to developing symptoms of lactose intolerance. 

Lactose intolerance is more common in cats, but the severity of symptoms varies from cat to cat. Some cats may tolerate lactose well, while others may quickly develop digestive problems such as diarrhoea, bloating and vomiting after ingesting lactose.

What Behaviour in Cats May Indicate Lactose Intolerance?

Lactose intolerance in cats is a condition in which a cat lacks sufficient lactase to break down lactose, causing an uncomfortable reaction in the intestines to ingested dairy products. Lactase is a digestive enzyme responsible for breaking down lactose into glucose and galactose for absorption in the small intestine. Lactase activity is usually lower in adult cats because they are carnivores and their ability to digest lactose decreases as adults. When cats ingest foods containing lactose, such as milk, the undigested lactose enters the large intestine where it is fermented by bacteria to produce gas and acid, causing symptoms such as diarrhoea, bloating and vomiting . 

Digestive symptoms

Frequent diarrhoea, soft stools or constipation, which may be accompanied by a fishy odour.

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Gastrointestinal discomfort

Cats may exhibit a distended abdomen, excessive licking of the fur, or an abdomen that appears sensitive when palpated.

Behavioural changes

Cats may become quieter or more anxious, lose their appetite and sometimes refuse to eat.

Signs of Dehydration

such as reduced skin elasticity, dry gums and reduced urine output.

General Discomfort

Cats may appear tired or listless and sometimes vomit.

These behaviours may be the result of your cat not being able to digest and absorb the lactose properly after ingesting it. If your cat exhibits any of these symptoms, it is advisable to stop giving lactose-containing food and consult your veterinarian for further diagnosis and treatment advice. Your veterinarian may recommend appropriate testing to confirm the diagnosis of lactose intolerance and provide a dietary management plan accordingly.

What are the Myths about Lactose Intolerance in Cats?

• Cats generally like milk

While many cats may be attracted to the taste of milk, this does not mean that it is safe or healthy for them. Adult cats usually lack enough lactase to break down the lactose in milk, leading to digestive problems. 

• Milk is the ideal drink for cats

Cow's milk is not an ideal drink for cats because adult cats have low lactase activity, and replacing regular meals with cow's milk over a long period of time may lead to malnutrition and health problems. 

• Goat's milk is a better choice

Although goat's milk contains slightly less lactose than cow's milk, it may still cause intestinal burdens in lactose-intolerant cats. For cats with lactose intolerance, lactose-free or low-lactose dairy products should be chosen. 

• Cats can try milk in moderation

Even if your cat seems to have a fondness for milk, it should be given with caution and watched for reactions. If diarrhoea or other signs of indigestion occur, feeding should be stopped immediately. 

• Using human baby lactase works for cats

There is no research on the efficacy of human lactase in cats and it is not known if it is suitable for cats. Lactose-free milk powder is a safer choice. 

• Yoghurt does not cause lactose intolerance

Yoghurt that has been fermented and broken down, in which the lactose has been broken down into half-saccharides, does not usually affect cats. However, it is still important to be aware of the temperature of the yoghurt, as too cold yoghurt may cause diarrhoea in cats. 

• All adult cats are lactose intolerant

Not all adult cats are lactose intolerant, some may still retain some amount of lactase or be able to adapt to small amounts of milk. 

How to Deal with Lactose Intolerance in Cats?

Lactase supplementation

Lactase enzyme preparations can be given to help break down lactose and reduce the digestive burden on the intestines before your cat consumes foods containing lactose. 

Probiotic therapy

The use of products containing probiotics, such as bifidobacteria and lactobacilli, can improve the intestinal micro-ecological environment, increase your cat's tolerance of lactose, and promote the absorption of nutrients. 

Electrolyte supplementation

For diarrhoea caused by lactose intolerance, oral rehydration salt solution or beverages containing electrolytes can be used to maintain water and mineral balance and prevent dehydration. 

Monitoring and managing body weight

Lactose intolerance may affect your cat's appetite and nutrient absorption, so your cat's weight and health need to be closely monitored to ensure they are receiving adequate nutrition.

Consult your vet

If your cat's symptoms of lactose intolerance persist or worsen, you should consult your veterinarian promptly to rule out other underlying digestive disorders and obtain professional advice on treatment. 

How to Prevent Lactose Intolerance in Cats?

• Choose low-lactose or lactose-free foods

Provide your cat with foods specifically designed for cats with lactose intolerance, which are often labelled as low-lactose or lactose-free to reduce the risk of digestive discomfort. 

• Avoid feeding lactose-containing dairy products

Don't feed your cat dairy products such as cow's milk or regular goat's milk that may contain high levels of lactose, as these foods can cause digestive upset and diarrhoea. 

• Offer alternatives

You can choose comfort milk or pet-friendly goat's milk powder, which are often processed to have a lower lactose content for lactose-intolerant cats.

• Introduce new foods gradually

If it is necessary to change the cat's diet, new foods should be introduced gradually to help the cat's digestive system adapt and reduce discomfort caused by a sudden change in diet. 

• Regular medical check-ups

Take your cat to the vet for regular medical check-ups to identify and treat any health problems, including lactose intolerance. 

With the above measures, you can effectively prevent digestive problems caused by lactose intolerance in your cat and ensure its health and well-being.

FAQs

Can My Cat Drink Milk?

Milk is usually not suitable for cats. Most adult cats and kittens have a weak ability to digest lactose because they lack sufficient lactase enzyme in their bodies to break down lactose. The lactose in milk cannot be broken down efficiently in the cat's intestinal tract, which can lead to indigestion, diarrhoea and other problems. 

Although a small number of cats may have some tolerance to the lactose in milk, it is best to avoid feeding cats milk for the sake of their health. If a cat accidentally ingests milk, its health should be closely monitored and a veterinarian should be consulted if necessary. 

There are ‘cat milk’ products on the market specially designed for cats, which are more in line with the needs of cats in terms of composition and nutrition, and can be used as a safe alternative. When choosing milk for cats, ensure that the product is from a reliable source, choose regular brands and pay attention to the ingredient list of the product, avoiding products with too many additives or sugar. 

Why Do Cats Love Milk So Much?

The reason cats like milk may be related to their natural preference and love of sweet flavours. At a young age, cats take milk from their mothers, which may give them a natural preference for milk products. The texture and temperature of milk may also appeal to cats for comfort and pleasure. In addition, the fat and lactose in milk (although many adult cats are lactose intolerant) can provide extra energy, which is attractive to active kittens . 

Can I Give My Cat Lactose Free?

Lactose-free foods provide a safe dietary option for cats with lactose intolerance, helping to prevent digestive upset and support their overall health. When introducing new lactose-free foods, it should be done gradually and the cat's response should be monitored to ensure that the food is appropriate for their specific nutritional needs . 

Lactose-free foods for cats can be effective in avoiding digestive problems associated with lactose intolerance. Lactose intolerant cats ingesting lactose may suffer from diarrhoea and bloating due to a lack of sufficient lactase enzyme to break down the lactose. Lactose-free foods contain lactose that has already been broken down or is at very low levels, making them safe to eat and helping to maintain your cat's intestinal health and balance. 

Although lactose-free foods are safe for cats with lactose intolerance, it is still important to be aware of other ingredients in the product when choosing a lactose-free pet food. Some lactose-free foods may have added additives or artificial ingredients that are not favourable to cats. Therefore, it is advisable to choose reputable brands and read ingredient labels carefully to ensure the food is suitable for your cat's overall nutritional needs. 

Conclusion

Despite the common belief that cats love milk, most adult cats are lactose intolerant and can’t properly digest dairy products. Feeding your cat milk or other dairy items can lead to digestive problems, including diarrhea, vomiting, and discomfort. Instead, opt for lactose-free milk or other safe treats that won’t harm your feline friend. By understanding your cat’s dietary needs and avoiding harmful foods, you can keep them healthy and happy.