How Does Dog Digestion Differ From Humans?

by Sydney Hess

Woman on couch  reading a book with dog looking at her

A dog’s digestive system is broken down by four main parts and so is a a human's , but what gets food from point A to point B is a bit different.

Have you ever wondered what really happens inside our pups’ bellies? Dogs and humans tend to share more than just our bond. The similarities and differences of human and dog digestion can give us an understanding of what their ideal diet looks like and what foods may boost their health through digestion. 

A dog’s digestive system is broken down by four main parts: the mouth and esophagus, the stomach, the small and large intestines, and the colon. A human's digestive system is also broken down by these same categories, but what gets food from point A to point B is a bit different for humans compared to our furry friends. 

1. The Dog's Mouth and Esophagus 

We’ve all heard the saying that a dog’s mouth is cleaner than our own. While this is unfortunately a myth (sorry to those who receive daily wet kisses), there is some truth backing why some might have believed this. Dog and human saliva both contain antibacterial and antimicrobial properties, however this shouldn’t be taken as permission to not wash your hands after handling a slobbery ball. Dog saliva can still potentially transmit bacteria and even parasites! 

For humans, saliva is used as the first step in digestion as it contains enzymes that begin the process of breaking down food. Dog saliva lacks the enzymes that human saliva contains, rendering its main purpose as lubrication to get the food down the dog's esophagus. 

A human mouth is designed to grind down food for optimal digestion, and has the ability to move the jaw side-to-side. A dog’s mouth can only open and shut, as their teeth were made to rip and tear rather than to grind. While both humans and dogs are considered omnivores, human teeth most closely resemble those of herbivores and dogs most closely resemble those of carnivores. 

2. Dogs' Stomachs

How can dogs eat things like poop and not get sick, while humans can’t even stomach eating 4 day old leftovers? A dog’s stomach produces roughly 100 times the amount of acid compared to a humans. An extremely acidic stomach has the ability to kill off pathogens before the stomach contents move onto the intestines. A dog’s stomach acid is also partly to credit for their ability to digest larger chunks of food. Humans experience optimal digestion after thoroughly chewing our food, but thanks to evolution, dogs can digest and pass much larger pieces of food much like their carnivorous ancestors. Dogs also tend to keep food in their stomachs for longer amounts of time as compared to humans, so their stomach acid can do the work in digestion. 

3. The Small and Large Intestine 

The intestines are where nutrient absorption takes place, and there are a few notable takeaways when looking at the natural diet of a mammal and their intestines. Dogs are omnivores, but commonly thrive on heavily meat-based diets. The intestines of dogs are shorter than humans so that food is more quickly moved through the intestines and there is a lesser chance of illness from the consumed food. Dogs are known to be scavengers, and oftentimes what they see as food is not something that should stick around in the GI tract for very long. Humans have a longer digestive tract similar to herbivores, as an ideal human diet is primarily plant and grain based foods which take longer to digest.

4. The Colon 

The main purpose of the colon in humans and dogs is to absorb leftover nutrients, water, and electrolytes before the remaining matter “moves out”. This is the final step of the GI tract before unused nutrients are defecated. While it isn’t the most glamorous or interesting part of the digestive system, so much can be learned about our dogs (and our own) health by looking at the final product - the poo! 

How to Boost Dog Digestive Health Through Food  

If you’ve ever taken a probiotic and thought that your pup would possibly benefit from one of their own, you’d be correct! Probiotic foods and supplements are a wonderful addition to aid our pups' digestion on a daily basis. Probiotics boost digestive health by introducing good bacteria into the GI tract. This is especially helpful if your pup is experiencing a bout of tummy troubles, or has recently taken antibiotics. 

Pumpkin and other cooked, dog-safe squashes can help to alleviate both diarrhea and constipation. This is due to the high fiber content of squash, so it adds bulk to their stools while absorbing excess water. Ginger and chicory root can also act as digestive aids for dogs.

Slippery elm is an herb that comes from the inner bark of the slippery elm tree. Its use for digestion goes back centuries, and is commonly used in humans to aid digestive upset. This herb is completely dog-safe and will help calm a dog’s GI tract in times of need. The properties of this herb helps soothe the mucous membrane in the GI tract, reducing inflammation. As a bonus, it is high in fiber and acts as a prebiotic. 

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