Carbohydrate enzymes: amylase, lactase and more

Bread, rice, potatoes, oats, milk, beans and lentils: a large part of an everyday diet is carbohydrate. Before your body can use it, starch and the larger sugars have to be broken down into smaller sugars, and that takes several different enzymes.

This article explains what carbohydrates are, how your body breaks down starch and sugars, and the four carbohydrate enzymes in Goodness Digestive Enzymes: amylase, glucoamylase, lactase and alpha-galactosidase.

What are carbohydrates?

The US National Library of Medicine (MedlinePlus) describes three main types of carbohydrate in food:

• Sugars, which occur naturally in fruit, and in milk and milk products.
• Starches, also called complex carbohydrates, found in beans and chickpeas, starchy vegetables such as potatoes, corn and green peas, whole grains such as brown rice, oats and barley, and refined grains such as white bread and white rice.
• Fibre, the part of food that the body does not break down.

According to MedlinePlus, the body breaks sugars and most starches down into glucose. Fibre follows a different path, explained in Fibre enzymes. This article covers starch and sugars.

How does your body break down starch?

According to NIDDK, part of the US National Institutes of Health (NIH), starch digestion starts before you swallow. Saliva contains an enzyme that begins to break down starch while you chew. The pancreas then adds a digestive juice with enzymes that break down carbohydrates, and the small intestine completes the job with its own digestive juice. The NIH also notes that bacteria in the small intestine make some of the enzymes needed to digest carbohydrates.

That enzyme in saliva and pancreatic juice is amylase. MedlinePlus describes amylase as an enzyme that helps digest carbohydrates, made mainly in the pancreas and in the glands that make saliva.

What does amylase do?

Starch is made of long chains of glucose units. A 2013 review of enzymes in the journal BioMed Research International explains that alpha-amylase cuts the links inside these chains, producing smaller pieces such as glucose, maltose (two glucose units joined together) and maltotriose (three).

Alpha-amylase is the main form of amylase in humans, the review notes, and it is most prominent in pancreatic juice and saliva. Plants make it too, in seeds that store starch, and so do many fungi. That is why amylase can be produced from microbial sources for use in food.

What does glucoamylase do?

Glucoamylase is also known as amyloglucosidase. According to the same review, it works from the end of a starch chain, releasing glucose, and it can also cut the branch points where one starch chain joins another.

Amylase and glucoamylase therefore complement each other. Amylase cuts long chains into shorter pieces; glucoamylase trims glucose from the ends. In Goodness Digestive Enzymes, glucoamylase helps break down starch into glucose.

What does lactase do?

Lactose is the sugar in milk. MedlinePlus Genetics describes lactase as the enzyme that digests lactose, the sugar found in milk and several other dairy products.

Your own lactase is made by some of the cells that line the small intestine. These cells have tiny finger-like projections, together called the brush border, and that is where lactase works: it splits lactose into two smaller sugars, glucose and galactose.

The food industry uses the same reaction. A 2025 review of food enzymes in Food Science & Nutrition describes lactase being used to split lactose into glucose and galactose to make lactose-free dairy products.

What does alpha-galactosidase do?

Beans, lentils and chickpeas contain a group of sugars that most people have never heard of. A 2022 review in Frontiers in Plant Science describes the raffinose family of oligosaccharides, sugars such as raffinose, stachyose and verbascose, as abundant in legume seeds, including soybeans, lentils and chickpeas. Each is built from ordinary table sugar with one or more galactose units attached.

Here is the key point: according to the review, humans do not produce an alpha-galactosidase enzyme to digest these sugars in the intestine. They pass through undigested and are used by the bacteria in the gut.

Alpha-galactosidase is the enzyme that can split them. The review also lists traditional kitchen steps that lower the amount of these sugars in legumes: soaking, sprouting, fermentation and cooking. Soaking dried chickpeas or broad beans before cooking them, a familiar step for hummus or foul, is one of them.

Which foods do the four enzymes work on?

Many dishes combine all four: lentils with rice, bread with hummus and a glass of milk or a bowl of yoghurt on the side.

How do these enzymes fit into Goodness Digestive Enzymes?

In Goodness Digestive Enzymes, amylase, glucoamylase, lactase and alpha-galactosidase help break down starch, milk sugar and the complex sugars in beans and lentils. They form one of four groups; the others are covered in Protein enzymes: protease, bromelain and papain, Lipase and fat digestion and Fibre enzymes.

Because enzymes work on food, they are taken around meals; the reasons are explained in When should you take digestive enzymes?. The How to use page gives the directions and safety notes, and the Ingredients page lists all 13 enzymes.

Goodness Digestive Enzymes is a food supplement that supports healthy digestion. It does not replace a varied, balanced diet.