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Lactose Intolerance in Dogs – Symptoms, Diagnosis, Foods to Avoid & FAQ

↯ Key takeaway points

  • Dog lactose intolerance is a common issue that causes symptoms like diarrhea, vomiting, bloating, and flatulence.
  • Lactose intolerance in dogs occurs because their body does not produce enough lactase enzymes to digest lactose.
  • Symptoms of lactose intolerance in dogs include diarrhea, vomiting, lack of appetite, bloating, flatulence, weakness, weight loss, and accidents in the house.
  • Avoid dairy products that would trigger your dog's symptoms, including milk, cheese, butter, yogurt, frozen yogurt, ice cream, sour cream, and whipped cream.
  • Dairy-free probiotics may help to control symptoms in dogs with lactose intolerance.
Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Veterinarian and veterinary microbiologist working as a veterinary science lecturer at the UVAS, Lahore.
Published on
Wednesday 7 April 2021
Last updated on
Wednesday 19 July 2023
lactose intolerance in dogs
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With products like ice cream for dogs on the market, many owners find themselves asking questions about lactose intolerance in dogs. Can dogs drink milk? Will dogs get sick from eating yogurt? Dog lactose intolerance is a relatively common issue that causes symptoms like diarrhea, vomiting, bloating, and flatulence. Depending on your dog, these symptoms can range from mild to severe and can change over time.

Lactose intolerance in dogs is manageable by avoiding dairy products. Your vet will recommend that you eliminate all lactose from your dog’s diet, including milk, cheese, and cream. If your dog’s lactose intolerance is severe, even foods like canned tuna may be off the menu.

What Is Dog Lactose Intolerance and Why Does It Occur?

After weaning, puppies produce less lactase and can become lactose intolerant. But what is lactase, and why is it important? In short, lactase is an enzyme in the small intestine that digests lactose. So, if your dog has a lactase deficiency, their body does not produce enough lactase enzymes to digest lactose anymore. Dogs exhibit varying levels of lactose intolerance; some experience mild symptoms, while others experience severe clinical signs. This difference is because each dog produces a different amount of lactase. As your dog grows older and enters seniority, their lactase production can drop even lower – as such, older dogs often experience greater lactose intolerance than younger dogs.

Without the puppy’s higher production of lactase, milk passes through the GI tract of the adult dog undigested. The undigested sugar in the milk draws water into the colon which causes diarrhea. Then, the fermentation of bacteria and sugar leads to flatulence and discomfort. If your dog’s lactose intolerance is severe, drinking milk induces diarrhea and vomiting. These symptoms can be dangerous as they lead to dehydration.

Is Your Dog Lactose Intolerant?

The signs of lactose intolerance in dogs include diarrhea, vomiting, lack of appetite, bloating, flatulence, weakness, weight loss, and accidents in the house. Your dog may also experience stomach cramps. In most cases, these signs develop 30 minutes to two hours after ingesting dairy products. So, if your dog shows these signs within this time frame, they may be lactose intolerant.

Make sure to visit your vet before coming to a final conclusion, however, as these signs can indicate other intolerances and health problems as well. As well as this, do not try giving your dog dairy products to test this theory – doing so can make your pooch very ill. Abdominal pain, vomiting, and diarrhea can be signs of serious illness in your dog, and should not be diagnosed as lactose intolerance at home. Diseases such as parvovirus and canine distemper cause similar symptoms and can be fatal if not addressed by your vet.

Diagnosing Lactose Intolerance in Dogs

Lactose intolerance in dogs is usually diagnosable based on your pet’s symptoms. If your dog’s symptoms begin 30 minutes to two hours after eating a dairy product, it is likely that your dog has significant lactose intolerance. Sometimes this diagnosis is not so simple as other conditions can resemble lactose intolerance. Every dog experiences gas, nausea, and bloating at some point in their lives, and not every case signals a lactase deficiency.

Your vet may carry out some tests to rule out other conditions. To do this, your vet may take a blood sample for testing, or take a sample of your dog’s poop to test for parasites like worms. A full physical examination can also help to rule out other health problems in your dog. If your vet cannot find any other causes for your dog’s symptoms, a diagnosis of lactose intolerance might be given.

When you take your dog to the vet, make sure to be clear about their symptoms. Make a note of your pooch’s symptoms and when they happen. It will also help to make a list of the foods that your dog ate before the symptoms began. Did your dog eat dairy products? If you’re not sure, is there any evidence that your dog ate dairy? And are there any other possible causes of their symptoms?

dog lactose intolerance
Avoid dairy products that would trigger your dog’s symptoms.

What Foods to Avoid?

The best treatment for lactose intolerance in dogs is to avoid dairy products that would trigger your dog’s symptoms. The list of products may surprise you – many foods contain dairy, and some are not so obvious. Because of this, many owners are surprised to find that their dog experiences symptoms of lactose intolerance after eating “harmless” foods. Some owners do not connect their dog’s symptoms with the intolerance because they do not feed their pet common dairy products.

Among the most common dairy products are milk, cheese, butter, yogurt, frozen yogurt, ice cream, buttermilk, whey, sour cream, and whipped cream. Breaded or batter-dipped meats will also often contain lactose. Even foods like hot dogs, processed meats, and canned tuna can contain dairy products. Crackers, tortillas, breakfast cereals, bread, and soups may also contain lactose.

Precautions for a Lactose Intolerant Dog

First and foremost, always check the labels of your dog’s food to ensure that it does not contain any dairy products. Most dog foods do not contain lactose, but you may find a commercial dog food that is made with cheese powder from time to time. Once you are sure that your dog’s food is free of lactose, make sure to avoid all dairy products, too. Be sure to keep your dairy snacks secure and out of your pup’s reach. If your dog raids cupboards, consider moving dairy products into a more secure area of your home.

If your dog’s lactose intolerance is severe, your vet may recommend probiotics to help to control their symptoms if they arise. Probiotics are good bacteria that help your dog to digest their food and absorb nutrients, which can help to reduce gas and make your dog’s stools firmer. As lactose intolerance can cause diarrhea, gas, and bloating, a course of probiotics may help to reduce these uncomfortable symptoms. Ask your vet about dairy-free probiotics for your dog!

vet advice for lactose intolerance
When in doubt, consult with your vet!

Lactose Intolerance in Dogs – FAQs

Have any more questions or concerns about lactose intolerance in dogs? Feel free to refer to our Frequently Asked Questions section for more information. If in doubt about your dog’s health, always ask your vet for advice.

What are the symptoms of lactose intolerance in dogs?

The signs of lactose intolerance in dogs include diarrhea, vomiting, loss of appetite, flatulence, bloating, weakness, weight loss, and accidents in the house. Your dog may also show signs of pain due to abdominal cramping. To relieve abdominal cramps, your dog may stretch with their hind end in the air and hold the position. Other signs of abdominal pain include drooling, retching, and guarding the stomach against your touch. Overall, the symptoms of lactose intolerance tend to develop 30 minutes to two hours after eating substances containing lactose. Unfortunately, the symptoms of lactose intolerance can also indicate other problems with your dog. To be on the safe side, always check in with your vet when your dog shows new signs of illness, as lactose intolerance may not be the only health condition to blame.

Can dogs become lactose intolerant?

Once a puppy is weaned it naturally becomes lactose intolerant. This is because a puppy that no longer needs its mother’s milk no longer needs to produce lactase, the enzyme responsible for processing milk. As a result, weaned puppies will produce less lactase as time goes on. This process happens to every dog. However, the extent of this lactase deficiency varies from dog to dog. While one dog that still produces some lactase may have few symptoms of lactose intolerance, another dog that produces little lactase may have severe symptoms. Older dogs produce the least amount of lactase. This means that your senior dog can become more lactose intolerant over time.

Can dairy products cause diarrhea in dogs?

Dairy products can cause diarrhea in dogs. This is especially a risk when the dairy product is not non-fat or low-fat. Not only is dairy a source of lactose, which many dogs struggle to digest, but dairy products can often be high in fat. Fatty foods cause diarrhea in dogs as dogs do not process fat as well as humans. They can also cause pancreatitis, which results in other gastrointestinal problems such as vomiting and a lack of appetite. Certain dairy products will also cause diarrhea if they contain harmful ingredients like Macadamia nuts, chocolate flavoring, and xylitol. Not only are these ingredients frequent causes of diarrhea, but they are also toxic to dogs. Never give your dog dairy products that contain toxic ingredients. If your dog consumes a dairy product containing these ingredients, call your vet immediately.

Can dogs have lactose-free yogurt?

Your dog can have lactose-free yogurt as an occasional treat. Lactose-free yogurt is often made using almond milk or soy milk, which are both dense in calories and can contribute to obesity in your furry friend. Plus, if you intend to give your dog lactose-free yogurt, you must ensure that it is plain and free of sweeteners. Added sugars are unhealthy for dogs, and some, like xylitol, are even toxic to our furry friends. You must also check that the flavor is safe for your dog. Chocolate, for example, is toxic to dogs and should never be given, even in a lactose-free yogurt.

Is cheese bad for dogs?

Cheese itself is not toxic to dogs, and can be given in small amounts as a treat, but is not necessarily good either. Dogs with lactose intolerance, sensitive stomach, or kidney problems should not eat cheese. There are also cheeses that are unsafe for dogs, such as those containing onion and garlic. Blue cheese is also unsafe for dogs – the fungus included in this cheese can cause vomiting, diarrhea, and high temperatures in dogs. Cheese is also high in fat which can lead to pancreatitis if eaten in excess. To be on the safe side, only give your dog cheese as an occasional treat, and only do so if your dog does not have any specific dietary needs.

Is lactose-free milk good for dogs?

In theory, lactose-free milk is less dangerous for dogs than regular milk but still isn’t good for them. This is because most lactose-free milk is produced by adding a man-made version of lactase to the milk. This enzyme breaks the lactose down into glucose, and galactose, saving the lactose from being processed by the body. Other manufacturers filter the lactose out themselves. While it is better that lactose-free milk contains less or no lactose, it still has the same nutritional profile as regular milk – this means that milk is packed with calcium, which, in excess, causes increased thirst and urination. In some dogs, prolonged excessive calcium intake contributes to the development of kidney and bladder stones.

Is almond milk bad for dogs?

Almond milk is made by processing almonds, which are not bad for dogs in moderation. However, almond milk contains extra calories. Just one cup of almond milk can contain 100 calories, meaning that it could contribute to obesity in your dog. And, since dogs are not equipped to process milk after weaning, these calories are devoid of the nutrients that your pooch really needs. Some almond milk is made with sweetener as well, potentially leading to tooth decay as well as obesity. Artificial sweeteners are even more of a problem for dogs; especially xylitol, which is highly toxic.

Are bread and milk good for dogs?

Dogs can eat bread and milk in moderation. Plain white bread and wheat bread are usually safe, as long as your dog has no allergies, and usually will not cause any stomach upsets. Feeding your pooch bread as a treat occasionally will not harm them, provided that they also receive a complete and balanced diet and get plenty of exercise each day. However, bread has little nutritional value for a dog and can lead to obesity if given in excess. Similarly, milk holds little nutritional value to a dog and can trigger symptoms of lactose intolerance. So, combining bread and milk as an occasional treat may be safe, but this is not necessarily good for them.

What foods are high in lactose?

Foods that are high in lactose include milk, buttermilk, cheese, butter, yogurt, frozen yogurt, ice cream, sour cream, and whipped cream. If your dog has a significant lactose intolerance, it is best to avoid all foods that contain lactose. You will also need to eliminate foods that contain smaller amounts of lactose, such as crackers, tortillas, and breakfast cereals. Even foods like canned tuna and processed meat may contain lactose. If your dog’s intolerance is severe, it is best to avoid these products too. In line with this, be sure to double-check the foods that you give to your dog to make sure that they don’t contain any hidden dairy products!

Can dogs eat ice-cream?

Ice cream can be given in small amounts, but for dogs with obesity, diabetes, or dairy intolerance, ice cream can be a problem. The flavor of the ice cream is also an important factor to consider, as many flavors can be dangerous for dogs. Chocolate is dangerous as dogs cannot process theobromine, while green tea ice cream may contain high amounts of caffeine. Any ice cream containing raisins or grapes is also dangerous, potentially leading to acute kidney failure even in minuscule doses. Finally, some nuts found in ice creams can be dangerous for dogs. Macadamia nuts can be dangerous for dogs, while other types, like walnuts and almonds, are high in fat and can lead to obesity.

Lactose intolerance in dogs is a common issue that causes similar symptoms as seen in humans. If your dog shows signs of lactose intolerance, be sure to eliminate all lactose products from your dog’s diet and check in with your vet for further instruction. Your vet can diagnose your furry friend after ruling out other causes of their symptoms.

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