Cat Digestive System: A Closer Look at How It Works

As pet parents, we’re usually on top of what we feed our cats, working hard to ensure that they don’t ingest anything that has a chance of upsetting their delicate tummies. But while we are concerned with what goes into their bodies, we don’t always have a clear view of how the cat digestive system actually works, or how long it takes for our kitties to digest their food.

In this article, we’ll discuss the domestic cat digestive system in detail, including its anatomy, how food is digested, and how to optimize your cat’s gut health.

Understanding the Cat Digestive System

Before we get into how it works, let’s first break down the parts of a cat’s digestive system.

The “alimentary system” includes the:

• Mouth
• Esophagus
• Gastrointestinal tract 

The gastrointestinal system (or GI tract) is made up of the:

• Stomach
• Intestines
• Rectum
• Anus

Lastly, the GI tract receives further digestive support from abdominal organs, such as the:

• Pancreas
• Liver
• Gallbladder

As a whole, these organs make up the digestive system of a cat.

Differences Between Cat and Human Digestive System

The digestive system of cats contains the same organs and produces the same digestive enzymes as us humans. However, although certain enzymes (such as hydrochloric acid) are the same, cats’ stomachs produce six times more hydrochloric acid than humans do.

The feline intestinal tract is also not as long or coiled as it is in humans (or dogs for that matter), and cats lack an appendix. Additionally, the transit time of ingested food (ingesta) through the intestines is much longer in humans, reaching up to five days, whereas ingesta may move through a cat’s intestines within 12 to 24 hours.

How Do Cats Digest Food?

Next, let’s get into some specifics about how the feline digestive system works.

The alimentary system is constantly at work to help cats ingest and digest food, absorb nutrients, eliminate waste and toxins from the body, and assist the immune system (in part by keeping ingested bacteria out of the bloodstream). The digestive tract also secretes various chemicals, enzymes, and hormones to assist with digestion and nutrient use.

Mouth

The process of digestion initially begins in the mouth when the teeth begin to break up large chunks of food, and the salivary glands produce amylase to help tackle any starch your kitty may have ingested (however limited in a predominately carnivorous diet). 

Esophagus

Ingesta then slides down the esophagus to the stomach where it undergoes the most significant aspect of digestion as it is immersed in a chemical vat of hydrochloric acid and various enzymes in the stomach to help break it down into tiny usable nutrient molecules. 

Stomach

Once ingesta enters the stomach, it is inundated by a variety of enzymes and other chemicals to further break it down into usable nutrients. Ingesta is also mixed and squeezed to further aid in mechanical digestion.

Small and Large Intestine

Ingesta continues its cruise down the digestive tract to the small intestine, where it is broken down further by additional enzymes and bile. By this stage, the majority of ingesta has been broken down into small enough nutrients that can be absorbed through the small intestinal lining into the bloodstream, which carries them off to cells all over the body. 

These nutrients act as cellular building blocks to help construct tissues and organs and carry out their vital functions to keep the body working as well as possible.

Products that cannot be digested, such as insoluble fiber, and any additional waste products are then further processed by the large intestine. Such waste is dehydrated when excess water is reabsorbed through the large intestinal lining into the bloodstream to maintain hydration, and then the solid waste exits from the body during a bowel movement.

Rectum

The rectum is a small holding area at the end of the large intestine that stores feces until exit through the anus.

Pancreas, Liver and Gallbladder

While ingesta does not enter the pancreas, liver, or gallbladder, these organs produce substances to help support the stomach and intestines with digestion. 

The pancreas contains digestive enzymes that enter the small intestine, and it also produces insulin to help utilize and regulate glucose, the body’s top nutrient for energy use. 

The liver is a large organ in the upper portion of the abdomen that, among its many functions in the body, is involved in metabolism, detoxifying the body, storing nutrients (such as glycogen and fat), and assisting in protein and glucose synthesis. 

The liver also produces bile, which aids in fat digestion. Bile is then stored and later released when needed by the gallbladder, a small sac off the liver. 

The pancreas, liver, gallbladder, and small intestine are all in close proximity to one another, so infection or inflammation of one can often affect the others.

How Long Does It Take for a Cat to Digest Food?

In the average domestic feline, digestion occurs more quickly than in humans. The entire duration of food from entry to exit can reach 26.5 to 35.7 hours. [1] During this time, ingesta spends approximately 10 to 24 hours being digested (by the stomach for four hours and then the intestines for 12 to 24 hours), then is further processed before waste is eliminated.

The average timeline of digestion varies depending on a cat’s age, breed, size, weight, and diet. Kittens and smaller-sized cats tend to digest food more quickly, whereas digestion time is more variable among senior cats. (And speaking of kittens, very young kittens are initially unable to digest anything other than their mother’s milk or a similar substitute. They gain more digestive function by weaning age, which is 8 weeks old.)

Digestion also occurs more quickly with smaller meals. For instance, multiple mini meals throughout the day can decrease digestion time, while feeding larger amounts less frequently can lead to increased digestion time (as well as an increased risk of “scarf and barf,” in which cats can regurgitate their food if it’s gobbled up too rapidly). Additionally, wet food diets are digested more quickly than dry kibble.

Caring for Your Cat’s Digestive System

There are many ways you can care for your cat’s digestive system. Let’s go over some of the most common ones.

Diet

As cats are obligate carnivores, they require particular nutrients that only an animal-based diet can provide. A vegetarian diet can be deadly to cats, as deficits in taurine, arachidonic acid, vitamin A, and vitamin B3 occur when cats are solely fed a plant-based diet. That’s why it’s important to choose an appropriate cooked commercial cat food or other veterinary-guided diet to optimize your pet’s nutritional health.

Reputable quality cat food brands include Purina, Hill’s, Iams, Royal Canin, and Eukanuba. These companies have a veterinary nutritionist on staff to formulate diets, conduct extensive studies and feeding trials, and ensure good quality control. 

For kitties with sensitive tummies, ask your veterinarian about:

A sensitive skin and stomach diet:

A lower fat diet:

Diets higher in fiber:

Kitties with hairball concerns can also benefit from a specialty hairball control diet, along with regular coat brushing. 

Always seek nutrition advice from your personal vet before making a switch, and if you’re greenlit with advice to make the change, slowly transition from your cat’s current diet to a new one over 10 days to prevent GI upset.

Supplements

Certain supplements, if recommended by your vet, can be helpful to certain kitties. For instance, those with pancreas issues (such as exocrine pancreatic insufficiency, or EPI), may require digestive enzyme supplementation. Most healthy cats do not need this supplement, however. 

Furthermore, probiotics and prebiotics can be helpful to many cats, especially those with chronic diarrhea as caused by dysbiosis (an imbalance of good and bad bacteria in the gut). Not all probiotics are created equally, so always seek counsel from your veterinarian before introducing them to your cat.

Cat-Safe Grass

Although your cat is a carnivore, they may occasionally like to nibble a bit of cat-safe grass. Consuming cat grass in small amounts can aid your cat’s digestion, improving hairball concerns and constipation. Moderation is key, however, since kitties lack enzymes to fully break down a lot of grass, and too much can cause harm.

Mini Meals

If your cat eats too quickly and upchucks their food, switching to multiple mini meals or canned food can help. Additionally, switching your cat’s food bowl to a slow feeder can slow down their food ingestion to help improve overall digestion.

Weight Management

Aside from feeding your cat a good quality diet, the most important thing pet parents can do to protect their cat’s digestive and overall health is to keep their cats at a healthy weight. Obesity can not only worsen digestive issues, but it can further impair your cat’s health. Maintaining a healthy weight is an ideal way to keep your kitty’s tummy soothed and them purring for longer.

References
1. Peachey, S E et al. “Gastrointestinal transit times in young and old cats.” Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology vol. 126,1 (2000): 85-90. doi:10.1016/s1095-6433(00)00189-6