Digestive Enzymes and their Importance

The Digestive Enzymes are found in the body and in food to help break down and digest food once it is consumed. They can also be consumed by means of supplements and help digestive processes or people suffering from certain pathologies

Digestive Enzymes and Digestive Health

When we eat food we activate all the machinery of our digestive tract to obtain all its nutrients.

This is achieved by processing the food bolus through physical (chewing, mixing, stirring, transport, etc.) and chemical (digestive secretions: acids and enzymes) procedures.

Inadequate enzyme production can lead to digestive disorders, bloating, lack of energy and allergic-type reactions to food.

As a result, macro- (carbohydrates, proteins and fats) and micro-nutrients (vitamins and minerals) become available for absorption in the intestinal tract, and are thus incorporated into the bloodstream and used by the body for its various functions.

What are Digestive Enzymes?

Enzymes are proteins that have a region in their structure, known as the active centre, where they bind to a molecule and catalyse a certain chemical reaction.

Digestive enzymes help with the absorption of nutrients and the breakdown of food particles we eat.

Function of Digestive Enzymes

Enzymes are responsible for breaking down the more complex molecules obtained from food into much simpler particles that can be absorbed. The reaction they catalyse is hydrolysis (hydro = water, lysis = breakage), i.e. they break down the molecules in an aqueous medium.

This is why these digestive enzymes would be classified within the group of “hydrolases”.

In addition to fulfilling their biological function, digestive enzymes can be used for technological purposes in numerous industries such as textiles, paper, cosmetics or the production of detergents (among others).

What are the Digestive Enzymes produced by the Body?

Within the digestive secretions produced in the body, we can highlight 5 main types:

Carbohydrate Enzymatic Digestion

Carbohydrates can only be absorbed in their simplest form, i.e. in the form of monosaccharides (a single molecule), which is why we need enzymes to break down all the complex molecules into those that can be incorporated.

In this way we can differentiate between:

Amylase are found in saliva and pancreatic secretion, while disaccharidases exert their action on the villi of the small intestine.

Lactase deficiency

It is well known that a large part of the world’s population (approximately 70-75%) is deficient in the enzyme lactase. As mentioned above, this enzyme separates the galactose and glucose molecules that make up lactose, the sugar in milk.

The consequence of its deficit is that this lactose remains intact throughout the intestinal tract, remaining available to the action of the bacteria that populate the intestine.

As a consequence, gases are produced by fermentation which lead to swelling and abdominal pain, diarrhoea or flatulence. In other words, the characteristic symptoms of lactose intolerance appear.

Dietary fibre

Fibre comprises a particular group of carbohydrates. Although structurally they are, like starch, glucose polymers, the type of bonds that bind one molecule to another cannot be hydrolysed (broken down) by our enzymes.

However, this fibre can be metabolised by the bacteria in our colon, serving as food for them and encouraging their proliferation.

This is why dietary fibre is considered a prebiotic.

Enzymatic Digestion of Fats

As with carbohydrates, fat digestion begins in the mouth, under the action of the tongue lipase.

To be absorbed at an intestinal level, fats must be converted into simple forms that allow them to be absorbed in the form of micelles and/or free fatty acids (their less complex form).

Within this group, in nature we find saturated fatty acids, monounsaturated and polyunsaturated. The differences between them are basically marked by their structure, as both mono- and polyunsaturated fats have double bonds in their structure.

On the other hand, artificially the archi-conscious trans-fatty acids, can be created through a process of hydrogenation (introduction of hydrogen molecules into the structure) of mono- and polyunsaturated fats.

Fats are mainly supplied in the form of triglycerides through the diet, which make up 90% of total fat. The remaining 10% is made up of cholesterol and phospholipid esters.

Structurally, triglycerides are made up of a glycerol molecule linked to 3 fatty acids which may be all 3 the same or vary in all or some positions.

When they reach the stomach, another lipase enzyme breaks down the triglycerides into diglycerides (glycerol + 2 fatty acids) and fatty acids. Subsequently, the lipase produced in the pancreas will continue to process the fat from gastric emptying and generate fatty acids and monoglycerides (glycerol + 1 fatty acid).

Protein Enzymatic Digestion

Proteins are made up of chains or sequences (primary structure) of amino acids (single molecules), which fold up giving rise to different conformations (secondary, tertiary and quaternary structures), which will be key for the proteins to carry out their function.

For the protein to be digested it must be denatured and fragmented into simple fractions that can be absorbed.

Denaturation, broadly speaking, involves the loss of the secondary, tertiary and quaternary structures of proteins, making the chains of amino acids much more accessible to the enzymatic machinery responsible for breaking them down.

Two everyday examples of protein denaturation are the cooking of an egg (we go from a liquid to a solid consistency and make that protein more digestible) or in the manufacture of yoghurt, in which the protein is denatured by creating that characteristic gel-like structure.

In the first case we would be talking about a heat denaturation and in the second case a pH denaturation (by acidification of the medium).

Protein digestion begins in the stomach and not in the mouth, as was the case with fats and carbohydrates:

1. Here, pepsin is released, a proteolytic enzyme which is activated in an acidic medium (with the hydrochloric acid also secreted in the stomach) forming the so-called pepsinogen, and is then inactivated in the duodenum due to the higher alkalinity of this region.
2. Pancreatic juice, which contains very powerful proteases that will break down the protein into polypeptides (short chains of amino acids), is poured into the intestine.
3. Finally, other enzymes called aminopeptidases that are found in the intestinal villi end up breaking down these polypeptides into simple amino acids that are incorporated. However, there are specific transporters for di- and tripeptides, so these can be absorbed without the need to be broken down into amino acids.

In addition, there is evidence that suggests that some macromolecules as proteins or big size peptides, could be absorbed at intestinal level without the need of being decomposed.

Use of Digestive Enzymes in Food Technology and Health

Although their technological use is nothing new, they can now be used to produce or modify certain ingredients or change the textures of products.

The enzymes used by the food industry can be derived from animals, plants or micro-organisms (bacteria, fungi and yeasts).

The main enzymes introduced into production systems are synthesised by micro-organisms of the Bacillus and Aspergillus genera. We could highlight the following:

Digestive Enzyme Supplements

In general, people with exocrine pancreatic insufficiency (exocrine secretion contains digestive enzymes) and those who are lactose intolerant can benefit most from enzyme supplementation.

Recently, the use of enzymes is even being considered as a therapy in coeliac disease, something we will see later on.

However, the application of digestive enzymes in healthy individuals can encourage digestion processes and avoid certain disconformities.

Amylase

Although it is rare for poor digestion to occur due to starch consumption, except in cases of pancreatic insufficiency or if the ingested starch is resistant (this means that because of their structure they behave like a fibre, i.e. they are not digested), amylase enzymes are very useful from a technological point of view.

From them, we can decompose a starchy raw material (very long, heavy and branched glucose polymers) into simpler ones whose digestion and absorption is faster and more efficient.

This greater ease of incorporation we know is fundamental when it comes to regenerating muscle glycogen deposits immediately after training or demanding competition.

Lactase enzyme or β-galactosidase

As mentioned above, people who are intolerant to milk sugar are either lacking in this enzyme, or contain it in insufficient quantities to digest all the lactose provided by the food.

The industry is capable of synthesising lactase from fungi and yeasts, incorporating it into its products and digesting the lactose fraction that might cause discomfort when ingested. In this way a product is obtained that is suitable for lactose intolerance.

Depending on the origin of the enzyme, its speed of action and effectiveness will vary, so different action times and/or amounts of lactase may be required depending on where it comes from. For example, lactase from the micro-organism Kluiveromyces lactis has been shown to be more efficient than that obtained from Aspergillus niger.

In addition, there are lactase drugs that can be consumed before taking a dairy product to prevent complications.

Lipase

Traditionally, lipase of porcine origin has been used in patients with exocrine pancreatic insufficiency (EPI) to enable these patients to digest and absorb fat. Lipase forms part of most enzyme complexes on the market, although the proportion included varies depending on each product.

Protease

There are occasions when the protein fraction of the diet is required to be supplied in the form of free amino acids or short chain peptides.

This is where protein hydrolysates (EvoHydro 2.0 and PeptoPro®, for example) come into play.

At an industrial level, protein hydrolysis can be sought for purely technological purposes or to improve organoleptic properties, but if we are talking about health, proteins can be hydrolysed to improve digestibility and to decrease their allergenicity.

The characteristics of the hydrolysate will depend on the type of protease used and the degree of protein breakdown required. For this reason, different enzymes can be used to process the same protein to obtain the desired product. It should be taken into account that sometimes bitter and moderately unpleasant flavours can be produced when a protein is hydrolysed too much.

Proteins and Food Allergies

The main difference between a food allergy and an intolerance is that in the case of the former, our immune system comes into action, generating a defence response against a food or component of it.

Major food allergens: peanuts, tree nuts, milk, eggs, wheat, soy, fish, and crustaceans

When it is a protein that causes the allergy, such as common allergies to milk or egg proteins, hydrolysis of these may be the only way for our immune system not to recognise them as allergens.

Some of the enzymes used to reduce protein allergenicity are pepsin, trypsin or papain, among others.

Bromelain

Bromelain is an enzyme that is not found in our digestive tract, but rather is obtained from pineapple. It is made up of a mixture of proteolytic enzymes.

Studies show that it can be absorbed at an intestinal level and preserve its functionality even at a blood level.

It should be noted that its level of activity varies depending on the method of extraction and even on whether it is extracted from the fruit or the stem.

This enzyme has protease activity and could therefore be used as a supplement in cases of pepsin and/or trypsin deficiency (human enzymes responsible for digesting proteins).

Amongst others, bromelain stands out for its anti-inflammatory and antimicrobial action. Some in vitro studies even attribute to it certain functions that would trigger a protective effect against cancer. But much research remains to be done on the latter, so let’s not get too far ahead of ourselves.

Papain

Like bromelain, papain is a proteolytic enzyme derived from a plant, in this case from the papaya.

As it has been observed, the ingestion of papain could be helpful in inflammatory processes, in the healing of wounds, in the improvement of post-exercise recovery and of course in digestive processes.

Enzymes and Coeliac Disease

Although the only treatment for coeliac patients today is to follow a gluten-free diet, there are some currents that position PEP (prolyl endopeptidase) enzymes as a possible alternative for patients.

Gluten is the main protein provided by some cereals such as wheat, barley or rye.

Combination of Enzymes and Probiotics

Throughout this article we have seen that each enzyme plays a more than relevant role in the treatment of the numerous digestive disorders. A new and promising area of study is whether the incorporation of certain probiotics could have an enzyme-enhancing effect.

It is too early to conclude on this subject, but there is no doubt that research should continue in this area.

For example, yoghurt producing bacteria hydrolyse lactose during fermentation and continue to exert their action in the digestive tract.

Another case is that of Aspergillus niger, which produces PEP enzymes, which, as mentioned above, could be useful for coeliac patients.

Digestive Enzymes and Ageing

Malnutrition is one of the main problems we encounter in older people.

To some extent, one of the causes of this malnutrition may be the very wear and tear or disease of the body’s organs that comes with ageing.

In fact, it has been observed that both the size of the liver and the volume of blood it supplies decrease with age, similar to what happens to the kidneys. A negative correlation between age and pancreatic size has also been observed in the pancreas.

Changes in size, structure and irrigation will influence the secretive capacity of this body.

Numerous studies in which duodenal content has been analysed have shown a lower concentration of pancreatic enzymes in samples of older people when compared with those of younger individuals.

A clear example is that when divided into 3 population groups (<40 years, 40 – 65 years and >65 years), lower volumes of pancreatic secretion and lower enzyme concentrations have been recorded in older individuals.

In view of the above, it seems that the intake of exogenous enzymes could be beneficial in older people, as they could reverse and prevent many symptoms associated with malnutrition.

Contraindications or Adverse Effects of Digestive Enzymes

According to a meta-analysis published in 2017, discomfort related to the application of digestive enzymes such as abdominal pain or flatulence is not very common. However, they could occur in cases of excessive doses or an allergic reaction to the source from which they are extracted.

Conclusions

Digestive enzymes are the agents responsible for breaking down food into simple nutrients that can be absorbed throughout the intestinal tract. Most are released in digestive secretions, but some exert their action in the intestinal villi.

The administration of exogenous enzymes (amylase, lipase, protease, lactase) from animal, vegetable or micro-organism sources is a fundamental tool in the management of exocrine pancreatic insufficiency and other diseases such as lactose intolerance.

Healthy individuals can also benefit from taking them if they often suffer from heavy digestion after eating certain foods.

There are enzymes from plants such as pineapple and papaya, which, although not part of the human enzyme pool, can aid digestion and have certain anti-inflammatory and antimicrobial properties that may be beneficial to health.

Sources

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6. Rathnavelu et al., (2016). Potential role of bromelain in clinical and therapeutic applications (Review)
7. Roxas (2008). The role of enzyme supplementation in digestive disorders.
8. Corgneau et al., (2015). Recent advances on lactose intolerancie: Tolerance thresholds and currently available solutions.
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10. Williams et al., (2014). Are intact peptides absorbed from the healthy gut in the adult human?
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