Digestion

What Are Digestive Enzymes?

Digestive enzymes help break larger nutrients into smaller components that can be absorbed and used by the body. Understanding where these enzymes act — and what happens when nutrients escape digestion — is central to understanding the nutritional environment further along the canine gut.

Science explainer

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Science explainer

Focus

Digestive enzyme activity and nutrient breakdown

The big question

Food contains nutrients in forms that are often too large or complex to be absorbed directly.

Before the body can make use of many of them, they need to be broken down into smaller components.

Digestive enzymes help carry out this process.

Different enzymes act on different types of nutrients, and their activity forms part of the wider digestive system that determines what is absorbed earlier in the gut and what continues further downstream.

So when we talk about digestion, one of the most useful questions is:

What role do enzymes play in deciding what the body absorbs — and what remains available later in the digestive tract?

How do scientists study it?

Digestive enzymes act as biological catalysts.

They speed up chemical reactions that break larger nutrient molecules into smaller components without being consumed in the process.

Different enzymes have different targets.

Amylases act on starch.

Proteases help break proteins into smaller peptides and amino acids.

Lipases help break down fats.

Other enzymes act on more specific carbohydrates and plant-derived compounds.

In the dog, digestive enzymes are produced within the body, including by the pancreas and tissues of the gastrointestinal tract.

Their activity works alongside other digestive processes such as chewing, stomach mixing, acidification, bile secretion and intestinal movement.

Together, these processes influence how effectively nutrients are broken down before they reach the lower digestive tract.

What can we measure?

Scientists can study digestive enzymes in several ways.

Enzyme activity

Laboratory assays can measure the activity of specific enzymes under defined conditions.

Nutrient digestibility

Researchers can estimate how much of a nutrient is digested and absorbed rather than recovered later in faeces.

Digestive products

The smaller molecules produced during digestion can also be measured to understand how nutrients are being broken down.

Downstream effects

Because digestion influences what continues through the gastrointestinal tract, researchers may also examine microbial composition, fermentation products and metabolites further downstream.

Looking at these different measurements together can help connect digestive activity with the nutritional environment encountered by the microbiome.

What have we learned?

Digestive enzymes are highly specific.

An enzyme that acts on one type of nutrient may have little or no effect on another.

Their activity is also influenced by the environment around them, including factors such as pH, temperature, substrate availability and transit time.

This means digestion is not simply a matter of whether an enzyme is present.

It is about whether the right enzyme encounters the right substrate under conditions that allow it to function.

The amount of nutrient that is successfully broken down and absorbed earlier in the digestive tract helps determine what remains available further downstream.

That makes enzyme activity relevant not only to nutrient digestion, but also to the wider nutritional environment within the gut.

Why does this matter?

Digestive enzymes sit at an important point between diet and the microbiome.

Food enters the digestive system as a mixture of nutrients.

Enzymes help transform some of those nutrients into smaller components that can be absorbed.

What is not digested or absorbed continues further through the gastrointestinal tract.

That creates a simple but important relationship:

Diet → Enzyme activity → Nutrient breakdown → Substrate reaching the microbiome

This does not mean enzymes alone determine what happens in the gut.

Digestion involves many interacting processes, and the microbiome itself contributes additional metabolic activity later on.

But understanding enzyme activity helps explain why the nutritional environment reaching microbial communities can be different from the food originally eaten.

For a closer look at amylase, protease and lipase, read our guide to digestive enzymes in dogs.

To learn about the naturally occurring enzyme activities in our barley ingredient, read about Enzyme Rich Malt Extract.

For the ingredients and feeding guide of CaniNectar, see the product page.

To see how enzyme activity fits within the wider digestive system, explore our guide to dog gut health, digestion and the microbiome.

What should we keep in mind?

Enzyme activity measured in a laboratory does not automatically tell us exactly how an enzyme will behave inside a living animal.

Conditions within the gastrointestinal tract change continuously.

pH, transit time, moisture, nutrient composition and interactions with other digestive processes can all influence enzyme activity.

The presence of an enzyme also does not mean that all available substrate will necessarily be digested.

And because nutrient breakdown depends on the entire digestive system, it is rarely appropriate to attribute a complex digestive outcome to one enzyme in isolation.

For that reason, enzyme activity is most useful when considered as one part of the broader process of digestion.

Sources and further reading

References

Further reading:

Hall EJ, Simpson JW, Williams DA. BSAVA Manual of Canine and Feline Gastroenterology. British Small Animal Veterinary Association.

Case LP, Daristotle L, Hayek MG, Raasch MF. Canine and Feline Nutrition: A Resource for Companion Animal Professionals. Mosby Elsevier.

Hooda S, Minamoto Y, Suchodolski JS, Swanson KS. Current state of knowledge: the canine gastrointestinal microbiome. Animal Health Research Reviews. 2012;13(1):78–88.

Wernimont SM, Radosevich J, Jackson MI, et al. The Effects of Nutrition on the Gastrointestinal Microbiome of Cats and Dogs: Impact on Health and Disease. Frontiers in Microbiology. 2020;11:1266.

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