Enzymes

Enzymes are essential for dogs and cats because these substances (proteins) are necessary for regulating certain chemical reactions in the body. Enzymes are biological catalysts—substances that can speed up or slow down a chemical reaction—and they ensure that less energy is needed for chemical reactions to take place. They are required for a wide range of metabolic reactions; without enzymes, these metabolic reactions could not take place or metabolic processes would proceed very slowly. Every enzyme in a dog’s or cat’s body has its own function; more than 80,000 different enzyme systems are known. Life is impossible without these enzymes.

Enzymes can be divided into digestive enzymes and metabolic enzymes.

1. Metabolic enzymes. These enzymes act as catalysts in living cells. They are essential for maintaining the body’s balance because they are needed to regulate and control almost every chemical reaction in the body related to metabolism. That is why these metabolic enzymes are present in all the body’s cells, tissues, and organs.

2. Digestive enzymes. Intrinsic digestive enzymes are enzymes that the body produces and secretes itself to break food down into smaller, absorbable nutrients. Examples include the enzymes secreted by the gastric glands in the stomach and those secreted by the pancreas; these intrinsic enzymes are needed to break down fats, proteins, and sugars. In addition to intrinsic enzymes, there are also extrinsic digestive enzymes. These include protease (needed for protein digestion), amylase (needed to break down starch), and lipase (needed for fat digestion).

Digestion

Various enzymes are involved in the digestion of food. These enzymes are already present in the food or intestines and are responsible for breaking down food. But how exactly is food broken down?

When a dog or cat eats food, it first enters the stomach. The food contains enzymes that enter the stomach along with it. The stomach then carries out a large part of the predigestion of the food—no less than 75%.

The high acidity of the gastric juices inactivates the enzymes present in the food. These enzymes are too large and complex for stomach acid to digest. When the inactive enzymes enter a more alkaline environment—the intestinal tract—they become active again.

After predigestion in the stomach, the partially digested food enters the duodenum. Several organs involved in digestion come into play here. The pancreas produces enzymes that enter the duodenum through the papilla of Vater (a type of drainage duct). These enzymes then complete the digestion of proteins, carbohydrates, and fats.

In addition to the pancreas, the liver secretes substances that neutralize the acidity of the gastric juices and emulsify fats. This improves both digestion and absorption.

After the duodenum, the food slurry continues through the intestinal tract. Nutrients from the slurry are absorbed through the intestinal wall and then enter the bloodstream. This blood eventually reaches the liver, which filters it to prevent unwanted substances from circulating in the body. After the blood has been filtered, the nutrients are transported to cells throughout the body.

Waste products, undigested food, and bacteria eventually enter the large intestine and are then eliminated.

Digestive enzymes

Complex nutrients that cannot be absorbed by the body because they are too large are broken down by digestive enzymes into smaller subunits.

Three digestive enzymes are most common in an animal’s body: lipase (for breaking down fats), protease (for breaking down proteins), and amylase (for breaking down starch). These digestive enzymes come from the pancreas, where they are produced. After a dog or cat has eaten, the pancreas releases these enzymes into the intestines. The complex nutrients—proteins, starch, and fats—are then broken down there; after being broken down into smaller subunits, they can be absorbed through the intestinal wall.

As indicated above, three different digestive enzymes play an important role in breaking down nutrients: amylase, lipase, and protease.

1. Amylase. This enzyme is produced in the pancreas. The pancreas then releases amylase into the duodenum (the beginning of the small intestine). In the small intestine, amylase breaks down starch, which is ultimately converted into glucose; other enzymes are also involved in this process. The glucose then passes through the wall of the small intestine into the bloodstream.
   In humans, amylase is present in saliva, so starch digestion begins in the mouth. Dogs and cats do not have amylase in their saliva, so starch digestion in these animals begins only in the intestines. Dogs and cats also produce less amylase than humans, which means they are less able to break down carbohydrates.

1. Lipase. Both the pancreas and the small intestine produce this digestive enzyme. It contributes to the healthy functioning of the body’s cells. Lipase is also responsible for breaking down fats and enables the body to store fat sources for longer periods.
2. Protease. This enzyme is produced in several locations, namely the stomach, pancreas, and small intestine. Proteins themselves are too large to be absorbed through the intestinal wall. Once proteins have been broken down into smaller components, amino acids, the body can absorb them. Protease is responsible for breaking down these proteins.

When a dog or cat begins chewing, the production of digestive enzymes starts. Chewing sends a signal to the body that triggers the production and release of enzymes into the stomach and intestines. When a four-legged animal receives a balanced diet, it will have no problems breaking down and absorbing all the nutrients from its food.

Digestive enzymes break nutrients down into smaller pieces so the body can absorb them. Once a puppy has been weaned, its body begins producing these enzymes itself. Healthy dogs are able to produce their own digestive enzymes and also receive an additional boost through their diet.

Normally, it is not necessary to supplement dogs or cats with digestive enzymes when they are healthy. However, if a dog’s or cat’s body is unable to produce digestive enzymes itself, a digestive enzyme supplement is necessary. The pancreas is often the cause, as it may fail to produce the required digestive enzymes. This can have various causes. For example, the pancreas may be inflamed, or an animal may suffer from Exocrine Pancreatic Insufficiency (EPI). However, EPI is rare and is often breed-related.

When the pancreas cannot produce the correct digestive enzymes, food passes through the body without the necessary nutrients being absorbed. These nutrients are too large and complex to be absorbed through the intestinal wall; digestive enzymes are needed to break them down into smaller pieces. If the body cannot absorb the nutrients it needs from food, this can result in serious health problems. The various causes of insufficient digestive enzymes in the body are:

• Genetics. Although a dog or cat may be in optimal health, congenital health problems can nevertheless cause its body to produce too few digestive enzymes. The causes may vary. For example, an animal may have type 1 diabetes, which prevents the body from producing enough digestive enzymes. A pancreas that is too small can also cause the body to produce too few digestive enzymes.
• Inflammation. Inflammation in the intestines can cause problems. Inflammation can damage certain digestive organs, reducing their ability to produce digestive enzymes. Intestinal inflammation may result from poisoning, a poor diet, or a disease such as IBD (Inflammatory Bowel Disease), which causes chronic irritation in the intestines.
• Intestinal injury. This injury may be caused by, for example, a collision or a fall.
• EPI (Exocrine Pancreatic Insufficiency). When an animal suffers from EPI, the pancreas produces too few digestive enzymes. This is because the pancreatic cells that produce these enzymes have been damaged by the condition. It is important to give dogs and cats with EPI digestive enzymes through a supplement or, for example, by feeding fresh tripe; fresh tripe contains digestive enzymes.