Digestive Enzymes: Types and Function

What are digestive enzymes, and what do they do?

Digestive enzymes are proteins secreted by the gastrointestinal system that help break down the food we eat into smaller components easily absorbed by our body. Our food contains carbohydrates, proteins, fats and other micronutrients that give us the energy to perform daily tasks. The digestive enzymes play a crucial role in enabling our bodies to absorb nutrients from the complex food we consume.

Different digestive enzymes types are secreted by various organs and glands in the digestive system, including:

• Salivary glands in the mouth
• Stomach
• Pancreas
• Small intestine

The enzyme types secreted by these organs work together to ensure that our food is processed more simpler, allowing our body to extract the maximum nutrients.

In a healthy human being, the production and secretion of enzymes in the digestive system are regulated by various hormones and other signals. These work in coordination to ensure that the right amount of each enzyme is synthesised at the right time.

What causes insufficient secretion of digestive enzymes? 

When the pancreas and small intestine cannot synthesise sufficient digestive enzyme types to digest food properly, this condition is called Exocrine Pancreatic Insufficiency (EPI). When the salivary glands in the mouth cannot secrete enough digestive enzymes, this condition is called hyposalivation. When the stomach cannot produce enough digestive enzymes, this condition is called hypochlorhydria.

These conditions occur due to a variety of factors, including:

• Ageing
• Injury
• Medications including proton pump inhibitors (PPIs) and H2 receptor blockers
• Alcohol consumption
• Certain medical conditions such as Sjogren’s syndrome, Pancreatitis, Cystic Fibrosis, Shwachman-Diamond Syndrome, pancreatic cancer and others
• Surgical removal of the pancreas

Other factors that lead to insufficient levels of digestive enzymes types include:

• People with gastrointestinal disorders such as irritable bowel syndrome (IBS), Crohn’s disease, or ulcerative colitis
• People who follow a vegetarian and vegan diet. These diets are high in fibre and low in digestive enzymes.
• Individuals with food intolerances such as lactose intolerance, gluten intolerance, or other food intolerances.

What are the Symptoms of Digestive Enzyme Insufficiency?

The lack of digestive enzymes types leads to various complications, including:

• Malnutrition 
• Dehydration 
• Mineral and Vitamin deficiencies
• Bloating 
• Abdominal pain
• Diarrhoea
• Constipation
• Weight loss
• Pancreatitis

If you are experiencing these symptoms, your body might not be making sufficient digestive enzyme types. It is essential to consult your doctor for proper evaluation and management.

What are various digestive enzymes types?

There are several different types of enzymes in the digestive system. Each of these enzymes performs a specific function. These enzymes are as follows:

Amylase is the digestive enzyme secreted by salivary glands and the pancreas. It helps break down starch and glycogen in carbohydrates into glucose. 

1. Amylase

There are two types of amylase found in our bodies:

Salivary amylase or Ptylin: Salivary amylase is secreted by the salivary glands in the mouth and starts digestion in the mouth and oesophagus. It helps breakdown down starch into maltose, a disaccharide.

Pancreatic amylase: Pancreatic amylase is secreted by the pancreas into the small intestine, which continues the breakdown of starch into maltose.

These amylases have a different level of specificity for the type of bonds it cleaves within starch molecules, which allows for the efficient breakdown of complex carbs into simpler forms.

The deficiency of amylase can lead to carbohydrate malabsorption and malnutrition.

2. Proteases

Proteases are digestive enzymes secreted by the pancreas and stomach. This helps break down proteins into smaller peptides and amino acids to be absorbed by the body. 

There are several types of proteases found in our body, out of which these proteases are responsible for digestion:

Pepsin: Pepsin is an aspartic protease in the stomach. It is secreted by specialised parietal cells and activated by gastric acid. It helps cleave the proteins at specific sites to generate smaller peptides.

Chymotrypsin: Chymotrypsin is a serine protease secreted by the pancreas and released into the small intestine, breaking proteins into amino acids.

Trypsin: Trypsin is also a serine protease secreted by the pancreas and is released in the small intestine, where it cleaves complex protein chains into smaller ones.

Elastase: Elastase is also a serine protease that helps break down protein.

Carboxypeptidase A: It is an exopeptidase that helps break complex amino acids.

Carboxypeptidase B: It is an exopeptidase that helps cleave a basic amino acid.

3. Lipases

Lipases are the digestive enzymes secreted by the pancreas and small intestine. It helps break down fats and oils into fatty acids and glycerol easily absorbed by the body.

The lipases involved in digestion include:

Gastric lipase: Gastric lipase is secreted by the stomach and responsible for the initial breakdown of dietary fats.

Pancreatic lipase: Pancreatic lipase is secreted by the pancreas into the small intestine. It helps break complex fats into simpler ones absorbed by the small intestine.

4. Lactase

Lactase is the digestive enzyme secreted by the small intestine. It helps break down lactose or milk sugar into absorbable forms such as glucose and galactose. The deficiency of lactase in the small intestine causes lactose intolerance, a condition in which you cannot digest milk and milk products.

5. Maltase

Maltase is the digestive enzyme secreted by the small intestine. It helps break down maltose, a complex sugar, into glucose easily absorbed by our body. The deficiency of maltase deficiency is known as sucrase-isomaltase deficiency. It is a condition in which the body cannot produce enough maltase to digest complex carbohydrates. It can lead to gastrointestinal problems such as bloating, gas, abdominal pain, and diarrhoea.

6. Sucrase

Sucrase is the digestive enzyme secreted by the small intestine. It helps break down sucrose, a complex sugar, into glucose and fructose that are easily absorbed by our bodies. The deficiency of Sucrase is known as a sucrase-isomaltase deficiency. It is a condition in which the body cannot produce enough Sucrase to digest carbohydrates. It can lead to gastrointestinal problems such as bloating, gas, abdominal pain, and diarrhoea.

How to treat digestive enzyme insufficiency?

The following methods can treat insufficiency of enzymes in the digestive system:

1. Digestive enzyme supplements

Some supplements are available over-the-counter to improve the symptoms of bloating, acid reflux and diarrhoea. These are available in the form of powder, oral capsules or tablets that are taken with meals. These supplements help break down carbohydrates, proteins, and fats to be absorbed easily. This supplement required depends on the type of enzyme deficiency as well as the severity of the deficiency.

For those with medical conditions such as cystic fibrosis, chronic Pancreatitis, and pancreatic insufficiency, Pancreatic enzyme replacement therapy (PERT) proves effective. It helps the body digest food effectively. In this therapy, oral supplements are taken with each meal and snack as guided by a doctor.

2. Surgery

Surgery for insufficiency of digestive enzymes is rarely performed. In the case of chronic Pancreatitis, surgeries for the removal of the pancreas are performed, followed by Pancreatic enzyme replacement therapy (PERT ) to help the body digest food. In some cases, transplantations can be performed to treat enzyme deficiencies.

Which foods contain natural Digestive Enzymes?

In addition to digestive enzyme supplements, dietary changes are also recommended to treat digestive enzyme deficiency. For example, dairy products are recommended to be avoided or consumed in smaller amounts in case of lactase deficiency. Similarly, in the case of celiac disease, it may be recommended to follow a gluten-free diet. Besides, certain foods can help increase the amount of digestive enzymes. These include:

• Papaya contains papain enzyme that helps digest proteins
• Pineapple contains bromelain, which helps digest protein
• bananas
• Fermented foods
• Sprouted grains
• Sauerkraut, finely chopped raw cabbage
• Raw honey
• Ginger
• fennel

Incorporating these foods can help improve the deficiency of digestive enzymes for maximum absorption of nutrients in the body if you experience persistent symptoms such as dehydration, malnutrition, weakness, bloating, foul-smelling stools, abdominal pain, diarrhoea, constipation and weight loss. In that case, seeking medical advice for proper diagnosis and treatment is good.

Frequently Asked Questions

Disclaimer: The information given in this article is true to our best knowledge. Still, we recommend you consult your doctor before following any treatment for gastrointestinal issues due to insufficient digestive enzymes.

References

• https://www.ncbi.nlm.nih.gov/books/NBK557738/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2576539#:~:text=Based%20on%20the%20mechanism%20of,found%20in%20mammals%20so%20far.