The optimal digestion of proteins and carbohydrates is an often-underestimated factor concerning sports performance and the building and strengthening of muscle tissue. However, with science proving the importance of digestive enzymes on the uptake and assimilation of performance nutrients – proteins and carbohydrates primarily – athletes, including bodybuilders, are now supplementing with an array of products designed to improve the breakdown and absorption of key food groups. Being critical for the assimilation of nutrients, digestive enzymes - designed to govern various physiological and chemical processes through working on, and maximizing, specific nutrients - are produced in our bodies naturally, and - as the main way we can obtain them, or so it is often thought - found in the foods we eat. Why is it then that so many people experience various digestive difficulties, and cannot properly absorb their food despite their best efforts?

Genetic differences (among those people with lactose and gluten intolerance, for example) can prevent some people from properly absorbing certain nutrients, while the increasingly poor quality of the foods we eat (often resulting from contaminated soil, spoilage and the use of nutritionally inert substances to manufacture foods) and the cooking methods used to prepare some of these foods (which can effectively destroy the enzymes designed to digest them) can render certain types lacking in important enzymes. For example, lean meat – a rich source of dietary protein and a staple for hard training bodybuilders – can be overcooked to where its natural enzymes are virtually destroyed (raw food advocates feel raw meat is the optimal way in which to ensure complete digestion of it). By adding papain available in supplemental form and found in pineapple, the protein contained in meat fibers can be better assimilated. In fact, certain fresh fruits and vegetables can be an excellent way to boost digestive enzyme levels to aid muscle growth and performance. However, even this approach can be flawed in that availability, nutritional quality, optimal quantity of nutrients delivered to the system and personal preference can impede any potential benefits to be derived. Further, all processed and chemical-laden foods are completely devoid of digestive enzymes and the raw, “healthy” foods we eat often do not contain enough to warrant using them as the primary way to obtain these important facilitators of digestion. And if all of this wasn’t worrying enough for those seeking optimal digestion and excellent health, the stomach acids we naturally produce to break down foods can actually inactivate the enzymes these very foods require for proper digestion (1). And it is for these reasons, and a greater awareness among athletes of the importance of digestive enzymes, that the popularity of these substances’ supplemental form has, in recent times, increased.   

What are digestive enzymes and what do they do?

By now we know that digestive enzymes are important for the breakdown and absorption of nutrients, but what are they exactly and how do they perform their vital functions?  

Digestive enzymes are classified by their substrates. These include the following (2):

-Proteases and peptidases, which split proteins into amino acids.

-Lipases, which split fats into three fatty acids and glycerols.

-Carbohydrases, which split carbohydrates such as starches into sugars.

-Nucleases, which split nucleic acids into nucleotides.

The enzymes that fall under these substrates, of which are used for digestion in the oral cavity, stomach, duodenum and jejunum and which are secreted by glands in the stomach, mouth, pancreas and small intestine, are protein-like substances that serve to spark and intensify chemical reactions within all cells of the human body. As catalysts for many vital functions, our trillions of enzymes serve important roles and must be available when needed. While certain of them can be produced in the pancreas (3) (for protein digestion primarily), we can only produce so many and to maintain a sufficient supply we must obtain them through the foods we eat and by supplementing our diets with digestive enzyme products. Since enzymes govern all that we do, a lack of them could mean degradation or death of the tissues they support. And since digestive enzymes ensure the complete digestion and assimilation of nutrients, and because from food comes life, it is all-important to ensure we have a ready supply to sustain the chemical reactions needed for continued survival.

Key enzymes used supplementally among athletes

While most of us will ensure (though not optimally) the continued ticking of our bodies enzyme-governed processes through eating well, for athletes it is imperative they not only eat a balanced diet with an emphasis on quality high biological value proteins and top-grade complex carbohydrates, but they must also ensure that the foods they consume are fully absorbed, something that is, as discussed, all but impossible with whole foods alone. Later in this article we will review several studies to show how targeted supplementation can boost enzyme levels above and beyond what can be expected through diet alone. For now, here is a list of the digestive enzymes needed by athletes, and indeed all of us, the various functions they govern, and the foods they can be found in.


Used for breaking down tough meat fibers to ensure the better assimilation of protein and transport of amino acids to the muscles. Present in papaya.


As a proteolytic enzyme, bromelain helps with the digestion of protein (when taken with meals) and serves as an anti-inflammatory (when taken between meals, on an empty stomach). Can be used by people suffering from arthritis, and those wanting faster, more complete absorption of proteins. Present in pineapple.


Breaks down starches into sugars, digests carbohydrates (polysaccharides) into smaller units (disaccharides) and ultimately into monosaccharides such as glucose. It begins the process of human digestion in the mouth where it is contained in saliva. It is also made by the pancreas (alpha amylase) and found in some plants. 

Glycine betaine:

Used to protect the body from osmotic stress, drought, high salinity or high temperature and permits cellular water retention thus protecting us from the effects of dehydration (4). Can be found in seafood, wheat germ and spinach.


A digestive protease, pepsin, released by the chief cells of the stomach (contained in the mucosal lining), degrades proteins into peptides and amino acids - these can then be readily absorbed by the intestinal lining.


Lipases are important in the digesting, transporting and processing of dietary lipids (fats, triglycerides and oils). Human pancreatic lipase – responsible for breaking down fats in the human digestive system – converts triglycerides into substrates found in ingested oils to mono-glycerides and free fatty acids (5). Primarily produced by the pancreas but also by the mouth and stomach, lipase has additionally been used by health care professionals to treat food allergies, cystic fibrosis and autoimmune disorders such as rheumatoid arthritis (6). It is not found in food.


Another of the proteolytic enzymes, trypsin acts to break down protein molecules found in foods to their component peptides and amino acids. Produced by the pancreas in inactive form, trypsin exerts its maximal enzymatic activity in the small intestine where it continues the process of digestion.   


Secreted by the small intestine, sucrase is the name given to several enzymes responsible for catalysing the hydrolysis of sucrose to its constituent molecules, fructose and glucose (basically, it breaks down larger sugar molecules to smaller sugar moleculesJ).

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