Enzymes in Our Body: From Digestion to Energy Production

Did you know that enzymes in our body are so efficient that a single enzyme molecule can process as many as 1000 substrate molecules per second? We all have these extraordinary biological catalysts, which perform thousands of vital functions in every cell of our body.

Indeed, every cell in our body has thousands of enzymes that collectively perform about 5000 different functions. From digestion to respiration, from muscle to nerve function – without these important proteins, our body simply could not function. It is particularly interesting that our digestive system enzymes work optimally under specific conditions – for example, stomach enzymes work best at pH 1.5, while intestinal enzymes work best at pH 8.

In this article, we will thoroughly examine how enzymes work in our body, what important role they play in digesting food and producing energy, and how we can maintain their optimal activity.

Enzymes in the Digestive System: Secrets of Food Breakdown

The digestive system is a miraculous mechanism, whose functioning is unimaginable without specific proteins – enzymes. Digestive enzymes are protein catalysts that accelerate biochemical reactions thousands of times over ^[1]. Their main function is to break down food into small molecules so that the body can absorb nutrients. Without a proper amount of enzymes, food remains insufficiently digested, which means it is not broken down into small particles ^[2].

Oral Enzymes: The First Stage of Food Processing

The digestive journey begins in the mouth. Here, saliva is released during chewing, containing the first digestive enzyme – amylase. This enzyme begins the breakdown of carbohydrates, especially starch, converting it into simpler sugars ^[3]. Salivary amylase continues to work as food enters the stomach, but its action stops when stomach acids neutralize this enzyme ^[4]. Interestingly, people who eat a lot of plant-based foods may additionally lack enzymes that break down plant fiber ^[1].

Stomach Enzymes: Protein-Digesting Substances

When food enters the stomach, parietal cells begin to secrete acids and enzymes, including pepsin – the most important stomach protease ^[4]. Pepsin is formed from pepsinogen, secreted by chief cells of the stomach, and is activated by hydrochloric acid ^[5]. The task of this enzyme is to initiate the breakdown of proteins into polypeptides. Stomach enzyme activity is most efficient when the pH is between 1 and 5 ^[5]. Other enzymes also act in the stomach – gastricsin and rennin, the latter being particularly important for infant nutrition ^[5].

Pancreatic Enzymes: Key Players in Digestion

The pancreas is the main gland of the digestive system, producing various enzymes that break down all nutrients ^[6]. The greatest digestive workload falls on this organ, as it is the only one in the human body that synthesizes and secretes the three most important digestive enzymes:

• amylase (to break down carbohydrates)

• trypsin (for proteins)

• lipase (for fats) ^[3]

It is particularly important to note that the fat-digesting enzyme lipase is produced in the human body only by the pancreas ^[3]. This enzyme is the most "problematic" because it is the least stable – it is broken down faster than other enzymes by organic acids, higher temperatures, or contact with various chemicals ^[3]. Pancreatic enzymes enter the duodenum, where intestinal enzymes, such as enterokinase, help activate them ^[5].

Intestinal Enzymes: Final Food Processing

In the small intestine, protein digestion occurs at three levels: luminal (enzymes in intestinal juices), membranous (enzymes at the villus membrane), and cellular (enzymes within the enterocyte itself) ^[5]. Here, pancreatic and intestinal juice enzymes, as well as bile produced by the liver, which is necessary for fat digestion, are active ^[3].

Glandular cells of the small intestine secrete aminopeptidases and dipeptidases, which belong to the exopeptidase group ^[5]. Here, lactase, which breaks down milk sugar lactose into glucose and galactose, sucrase, which breaks down sugar sucrose into glucose and fructose, and maltase, which breaks down maltose into glucose molecules, are also active ^[4].

Signs of enzyme deficiency can be varied: a feeling of heaviness and gas accumulation after meals, indigestion, nausea, constipation or diarrhea, chronic fatigue ^[1]. Enzyme production and secretion can be disrupted not only by various diseases but also by an unhealthy lifestyle ^[1]. Long-term enzyme deficiency can lead to obesity, weakened immunity, depression, and other health problems ^[5].

Thus, digestive enzymes play an extremely important role in maintaining our health. They not only help digest food but also ensure that the body receives all the necessary nutrients. Without these magical proteins, our body simply could not function.

Enzymes and Energy Production in Cells

Every cell in our body is like a small factory where complex energy production processes take place. All these processes are coordinated by special proteins – enzymes, which act as precise biological catalysts. Without them, our body could not convert food into energy, which is essential for absolutely all bodily functions.

Glycolysis Enzymes: Sugar Conversion to Energy

Glycolysis is the first stage of energy production, during which glucose (C₆H₁₂O₆) breaks down into pyruvate. Interestingly, this process does not occur in mitochondria but in the cell's cytosol, and it does not require oxygen ^[7]. Glycolysis consists of 10 enzymatic reactions involving different enzymes ^[8]. First, glucose is activated by phosphorylation using two ATP molecules. Later, a six-carbon molecule is broken down into two three-carbon molecules.

The glycolysis process has two main stages:

1. Preparatory stage – two ATP molecules are consumed

2. Energy recovery stage – four ATP molecules are produced

Thus, the final result of glycolysis is two new ATP molecules from one glucose molecule ^[9]. Also, during this process, NAD+ is reduced to NADH, which is later used in mitochondria for further energy production ^[7]. In the mammalian body, in addition to glucose, intermediate products of the breakdown of other substances (lipids, amino acids, glycogen) can also participate in glycolysis ^[8].

Mitochondrial Enzymes: The Center of Energy Production

Mitochondria are double-membraned cell organelles, also known as "cellular powerhouses" ^[10]. They are where the main energy production processes take place. Inside mitochondria, we find a matrix containing DNA, ribosomes, and various enzymes that regulate fatty acid oxidation and the tricarboxylic acid cycle ^[10].

One of the most important mitochondrial enzymes is citrate synthase – the main enzyme of the tricarboxylic acid cycle (Krebs cycle) ^[11]. It regulates energy production (ATP synthesis) during metabolism. Citrate synthase activity is an important indicator, often used as a marker for mitochondrial content ^[11]. Studies show that obesity and diabetes are often associated with poor mitochondrial function, and continuous physical activity can increase muscle oxidative capacity ^[11].

The mitochondrial electron transport chain consists of four protein complexes (I-IV) and mobile electron carriers – ubiquinone (CoQ10) and cytochrome c ^[1]. CoQ10 is a naturally occurring enzyme in the body, essential for cellular energy production, acting as a catalyst that facilitates the energy production process ^[12].

ATP Synthase: The Final Step in Energy Production

During electron transport, an electron flow is created, which is associated with the formation of a proton gradient across the inner mitochondrial membrane ^[1]. The energy accumulated in the form of a proton gradient is used for ATP production in Complex V (ATP synthase) ^[1]. ATP synthase has two main components: F₁ and F₀ ^[13]. This enzyme is special because it acts as a molecular motor, converting the energy of proton movement into ATP.

Adenosine triphosphate (ATP) is the primary, universal energy source for all cells ^[14]. Our cells do not have large ATP reserves, so ATP molecules are constantly synthesized ^[14]. ATP synthesis, which occurs in the mitochondrion, can be imagined as a windmill – the more we move, exercise, breathe, the more we "create wind" and stimulate the ATP synthesis process ^[14].

The role of mitochondria in energy production is so important that impaired function is associated with various diseases. Most modern human diseases are related to a lack of energy in the body: chronic fatigue, rheumatic diseases, chronic stress, diabetes, cardiovascular diseases ^[15]. Moreover, as the human body ages, the levels of important coenzymes like NAD+ decrease, leading to age-related processes – brain fog, weakened muscle function, slowed metabolism ^[16].

Thus, enzymes are indispensable participants in the energy production process, ensuring that our body receives enough energy for all vital functions.

Enzymes in Liver and Kidney Function

The liver and kidneys – two extraordinary organs that perform vital functions by removing toxins and regulating metabolism. The enzymes acting in these organs are like extraordinary chemists, constantly working to maintain our health. Let's look deeper into the activity of these irreplaceable proteins.

Detoxification Enzymes: Removal of Harmful Substances

The liver is the largest internal organ of the human body, performing one of the most important functions – detoxification. It acts as a vital filter, cleansing our body of harmful substances. First of all, liver enzymes are protein molecules that help various chemical reactions occur in this organ.

The liver's detoxification process takes place in two main stages. In the first stage, toxins are neutralized by liver enzymes, and in the second stage, these neutralized toxins are converted into water-soluble forms to be more easily eliminated through urine or sweat. Special enzymes are necessary for this process, and their activity requires various vitamins and trace elements, such as vitamin B, vitamin C, selenium, magnesium, sulfur, and amino acids.

More than 500 different types of enzymes have been found in the liver, participating in toxin removal. Three main groups of liver enzymes can be distinguished:

• Transaminases – aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT)

• Phosphatases – alkaline phosphatase (ALP)

• Dehydrogenases – lactate dehydrogenase (LDH)

An increase in ALT and AST enzymes may be associated with liver damage, such as hepatitis or cirrhosis. Meanwhile, a higher alkaline phosphatase level usually signals liver or gallbladder diseases. The GGT enzyme most often increases in people prone to excessive alcohol consumption or suffering from gallbladder diseases.

Kidneys also play an important role in toxin removal. Specific enzymes are required for the detoxification reactions that occur in them. Non-protein nitrogenous substances – urea, creatinine, and uric acid – have important diagnostic significance in evaluating protein metabolism and kidney function.

Regulation of Metabolism

Besides detoxification, the liver is the main metabolic laboratory. Most vitally important biochemical processes occur here, coordinated by a complex enzyme system. The liver stores vitamins (A, D, E, K) and minerals, breaks down proteins, produces bile, participates in immune processes, and produces glycogen – an important energy reserve.

Fat catabolism is another important process in which liver enzymes participate. This process involves the breakdown of triglycerides in adipose tissue, and the process is regulated by hormones. The fatty acid breakdown system consists of special beta-oxidation enzymes. The regulation of the activity of these enzymes is directly related to the final products of beta-oxidation and their further metabolism.

Cholesterol biosynthesis also occurs in the liver. This process is controlled by special enzymes, whose activity can be regulated at three levels: enzyme activity, enzyme quantity, and gene expression.

Enzyme production decreases with age, so it is believed that enzyme deficiency may be one of the causes of aging. The human body uses more and more enzymes for regeneration, while their production decreases. Due to various environmental factors and industrial food processing, our body no longer receives enough enzymes from food, which creates an additional burden on the liver and kidneys.

Finally, I want to mention that it is useful to perform health tests, which would include liver enzyme indicators, at least once a year. This helps to detect changes in time and prevent more serious liver diseases. After all, the liver is one of the few organs that has the unique ability to regenerate, but only as long as the damage is not too great.

Health Problems Caused by Enzyme Deficiency

Enzyme deficiency can lead to various health problems – from minor digestive disorders to serious congenital diseases. Our body relies daily on hundreds of enzymes that ensure the smooth running of biochemical reactions, so any deficiency inevitably affects health.

Congenital Enzyme Deficiencies

Some people are born with genetic disorders that lead to various cases of enzyme deficiency. Congenital lactase deficiency is a rare autosomal recessive disorder characterized by diarrhea appearing from infancy, hypercalcemia, and nephrocalcinosis ^[3]. The occurrence of this disorder is caused by a gene mutation that results in the absence of the enzyme lactase in the small intestine ^[3].

Acquired lactase deficiency is often a consequence of prematurity. Fetal lactase activity increases in late pregnancy, so premature newborns, aged 28–32 weeks, have lower lactase activity ^[3]. Secondary lactase deficiency can also develop due to infectious inflammation or autoimmune disorders damaging the small intestinal mucosa ^[3].

Age-Related Enzyme Changes

With age, enzyme production in the body naturally decreases. Studies show that 8-month-old calves had a total nitrogen content on average 2.1 times higher, and ammonia nitrogen content 1.7 times higher than 3 and 3.5-month-old calves ^[17]. This demonstrates how enzyme activity changes with age.

Also, as we age, the acidity of our stomach acid becomes more alkaline. In terms of enzyme production, this means an increased likelihood of a lack of the much-needed acidic "trigger" that begins to be produced when chyme enters the intestine ^[18]. Due to these changes, the likelihood of developing digestive disorders due to low stomach acidity or enzyme deficiency increases with age ^[18].

Lactase Deficiency and Other Common Disorders

Lactase deficiency is the most common enzyme deficiency in the world. About 70% of people worldwide no longer produce enough lactase to properly digest lactose in milk ^[19]. However, lactose intolerance is less common among people of European and Northwestern Indian descent ^[19].

The main symptoms of lactose intolerance are:

• bloating and pain

• gas accumulation

• diarrhea

• nausea or even vomiting ^[19]

Some people may also develop lactose intolerance after surgery or due to gastrointestinal diseases such as viral or bacterial infections ^[19]. Pancreatic problems, including cystic fibrosis, pancreatic cancer, and acute or chronic pancreatitis, can also lead to a deficiency of digestive enzymes ^[4].

Studies confirm that long-term enzyme deficiency can lead to more serious problems, such as obesity, weakened immunity, depression and anxiety disorders, premenstrual syndrome, fatigue, and autoimmune diseases ^[5]. Primarily, this is related to the body not receiving the necessary nutrients due to a disturbed digestive process.

How to Maintain Optimal Enzyme Activity

Our daily choices directly affect enzyme activity in the body. Although enzymes are naturally produced in our bodies, we can improve their activity with appropriate dietary and lifestyle decisions.

Impact of Nutrition on Enzyme Activity

Natural sources of enzymes are fresh and dried fruits, vegetables, and fermented foods. However, it is important to know that thermal processing at temperatures above 45°C and industrial processes destroy most of the enzymes in food. Therefore, cooking and baking food can significantly reduce enzyme content.

Excellent sources of enzymes include:

• Sprouted grains, raw leafy vegetables

• Pineapples and papayas (contain natural proteolytic enzymes)

• Fermented products: sauerkraut, kimchi, kefir, yogurt, and other fermented dairy products

Kimchi – spicy Korean side dishes – are particularly valuable because "Bacillus" species bacteria, which produce proteases, lipases, and amylases, appear in them during fermentation. These enzymes digest proteins, fats, and carbohydrates, respectively.

Enzyme Supplements: When Are They Useful?

The body's need for enzymes is increased by a faster pace of life, long-term stress, prolonged fatigue, and lack of sleep. Supplement use is also beneficial for chronic diseases, a low intake of fresh vegetables and fruits, prolonged medication use, or harmful habits.

Replacement digestive enzymes are especially important when:

• Pancreatic function is impaired or pancreatitis is present

• Constant bloating and a feeling of heaviness persist

• Gallbladder has been removed or bile production is disrupted

It is advisable to take digestive enzymes during or immediately after a meal. The recommended dose is 20,000-40,000 lipase units per meal.

Lifestyle Factors Supporting Enzyme Health

To ensure optimal enzyme activity, it is very important to stay hydrated – it is recommended to consume at least 2 liters of water daily. Proper hydration helps the body effectively absorb enzymes, allowing them to effectively break down food.

Regular physical exercise also improves enzyme activity – it helps food move faster through the digestive system, reducing the risk of nausea, bloating, and constipation. In addition, it is important to include probiotics in your diet, which help our bodies produce digestive enzymes.

However, successful enzyme activity is reduced by alcohol consumption, smoking, and stress, so avoiding or minimizing these factors is an important part of enzyme health. It is also essential to get enough rest, as sleep is an important process for enzyme production and renewal.

Conclusions

Thus, enzymes are indispensable agents in our bodies, performing thousands of vital functions. First of all, they ensure efficient food digestion and energy production in cells. In addition, enzymes play an essential role in liver and kidney function, helping to eliminate toxins and regulate metabolism.

Scientific research shows that enzyme deficiency can cause serious health problems – from digestive disorders to chronic diseases. Therefore, it is particularly important to maintain optimal enzyme activity in our bodies. We can achieve this by consuming fresh, unprocessed foods, fermented products, and, when necessary, high-quality enzyme supplements.

Finally, our daily choices – proper nutrition, regular physical activity, sufficient rest, and stress management – directly affect enzyme activity. By understanding the importance of these essential proteins and knowing how to maintain their activity, we can ensure better functioning of our bodies and overall well-being.

 

References

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This article does not represent the author's personal opinion and is not intended to promote food supplements. It provides general information not related to the purchase or use of specific products. If you have health problems, are taking medication or other supplements, consult your doctor or pharmacist before starting to use new supplements. Health decisions should be made based on your individual condition and, if necessary, in consultation with a healthcare professional. If you have any comments or questions about the content on this page, please contact us by email at studija@grasole.com.