The major issue with plant foods is the cell wall, a fibrous complex that surrounds the plant cells. A major part of these cell walls is something called cellulose. Cellulase is an enzyme that is an essential part of digesting this plant fiber, but it’s not something that we naturally produce in our bodies. Other species that eat exclusively plants have means to get around this.

For example, a cow has a four-chambered stomach, containing plenty of microbes that digest cellulose. This enables cows to get virtually all the energy they need from eating plants.  Some plant fibers are fermented and digested in the large intestine, while others are eliminated from the body, and cellulase is essential to digesting the fibers. It helps convert cellulose into beta-glucose, one of the most fundamental forms of energy in the body.  

We need cellulase in order to maximize digestion of fruits and vegetables, but we don’t produce it like other enzymes. The good news is that other organisms do produce cellulase naturally, like some symbiotic fungi, protozoa and bacteria. Many of these are contained in different types of plant food as well.  

Make sure when you are look for a supplement that it has a shit ton of cellulase in it and make certain that it is vegan: many pre-probiotic formulas are not. 


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  2. Abeles FB. Abscission: role of cellulase. Plant Physiol. 1969;44(3):447-52.