Remember that “good bacteria” you’re always hearing about? It really does exist.  Part of our digestive process naturally involves fermentation, right inside our bodies. This produces digestives aid such as cellulase.

Without these aids, all of the food we eat would be useless, simply traveling through our bodies without giving us any nutrition at all.  Below we’ll find out what exactly cellulase is, what it does, and why it’s so important.

What Is It?

Cellulase is a term used to refer to a group of enzymes that assist in the digestive process by breaking down cellulose, a component of the cell walls of plants and prevalent in high-fiber foods.

What Is Its Biological Role?

When we eat plant material that is very fibrous (think of broccoli stalks, asparagus, sweet potato peels and so on) it is too tough to be digested in the stomach or small intestine. It remains undigested until it reaches the large intestine, because of the tough cell walls surrounding the cells of plant materials.

These cell walls are composed primarily of cellulose. In order to glean optimal nutrition from these foods and digest them properly, our bodies need a way to break down that tough outer wall and lyse, or destroy, the cells. This is where cellulase [1] comes in--its sole job is to tear down the cell walls by breaking down the cellulose that holds them all together. 

Unfortunately, our bodies cannot produce cellulase on its own; that is why we cannot start the digestion process of cellulose until it reaches the large intestine. There, a plethora of “good bacteria” known as gut flora conduct and ongoing fermentation process of the foods we eat. A byproduct of this fermentation is cellulase, which is then able to get to work on the cellulose, breaking down that plant matter so that we can absorb all of the nutrients it holds.

When the cellulose is broken down it is transformed into more easily useable molecules such as monosaccharides like beta-glucose. Beta-glucose and other monosaccharides from cellulose digestions help even our body’s blood glucose level and maintain energy levels far better than simple carbohydrates.

This is because cellulose takes so much longer to digest than protein or starches that, after your body has sucked up all the energy available from these sources, the beta-glucose is just starting to become available for absorption after the cellulase has finished its job. In this way cellulase helps us get all of the “good stuff” from the green and fibrous plants we eat, rather than just passing them undigested as excrement.

How Does It Help Bodybuilders and People Who Work Out?

Everybody needs cellulase, regardless of lifestyle or fitness level, to properly digest fibrous foods. Fitness enthusiasts, though, should be concerned about maintain healthy gut flora to allow cellulase production.

In part because they will typically eat a wholesome diet high in these types of foods, and also because the proper digestion of cellulose and subsequent release of beta-glucose creates a longer period of respite from hunger and fatigue after eating, meaning you can do more with fewer calories.

What Foods Contain It?

Some, though not all, cellulose-containing foods also contain the cellulase you need to help digest them. This happy accident does not provide adequate cellulase to fully digest the plant fibers you’ve eaten; for that process it is crucial to have an intestinal environment that encourage positive gut flora such as cellulase.

How Much Of It Do You Need?

How much cellulase your body uses really depends on what you eat, [2] as a diet high in processed foods has little to no use for these enzymes. Your body generally makes what you need, and if you decide to supplement with a digestive enzyme blend containing cellulase, the best advice is right there on the label.

The proprietary blends in the supplements makes it impossible to provide a general recommendation; rather, simply follow the dosing instructions on the packaging.

Are There Risks Associated With Consuming Too Much Of It?

Cellulase is a natural part of a healthy gut. Consuming normal supplemental amounts will have no ill effects all else being equal. However, always consult with your primary doctor beforehand to ensure that your specific situation is cleared with a trained professional.

Are There Risks Associated With Consuming Too Little Of It?

Without the presence of cellulase in the large intestine it is impossible to properly digest fibrous plant material. If you have too little [3] of it in your body, you will excrete the plant matter undigested. This not only causes unpleasant physical symptoms such as cramps and diarrhea, but robs you of the nutrients that lie within.

Cellulase is just one small element of the digestive process, but the work it does is invaluable. Our bodies have developed specialized mechanisms to help us get the fuel we need from each type of food we eat, and plant matter contains tons of nutrients we would miss out on without this incredible enzyme group.


[1] Dr. Group, Edward. The Health Benefits of Cellulase. Global Healing Center, 2014.

[2] Undergraduate Journal of Science. Turning Waste Into Food: Cellulose Digestion. Dartmouth College, 2011.

[3] DC Nutrition. Enzymes: Digestive and Anti-Inflammatory. DC Nutrition.com, 2017.