Published January 9 2017
Many people reading this understand the importance of a healthy gut when it comes to achieving optimal thyroid health. The majority of thyroid conditions are autoimmune in nature, and most people with autoimmune thyroid conditions have gut issues in the form of a leaky gut and/or an imbalance of the gut flora. In fact, according to the triad of autoimmunity, a leaky gut is a necessary factor in ALL autoimmune conditions. While a leaky gut is a big factor in autoimmunity, a deficiency in digestive and pancreatic enzymes, as well as gastric acid and bile salts shouldn’t be overlooked.
Before talking about digestive enzymes, I’d like to go ahead and discuss some of the basics of digestion. Digestion of course involves the breakdown of the food you eat into smaller substances, which in turn are absorbed through the small intestine. Digestion actually begins in the mouth, and chewing your food helps to break it down, and this is an important part of the digestive process. The saliva in your mouth has an enzyme called salivary amylase, and this helps to break down carbohydrates. But there are other enzymes present in the mouth, such as lingual lipase, which aids in the digestion of fats.
Once the food makes it way down the esophagus and into the stomach, the gastric (stomach) acid helps to further break down the food you eat. The gastric acid consists primarily of hydrochloric acid and pepsin. And these are especially important to help break down the protein you eat, although having sufficient stomach acid is also important in preventing the overgrowth of bacteria and yeast. I’ll talk more about hydrochloric acid and pepsin later in this article.
The breakdown of food continues in the small intestine, as there are brush border enzymes, which includes maltase, lactase, and sucrase. In addition, the pancreas secretes proteolytic enzymes such as trypsin and chymotrypsin. Lipase is also secreted by the pancreas, and this breaks down triglycerides into free fatty acids. However, bile salts are necessary to break down the triglycerides as well.
Although I just discussed some of the basics of the digestive process, I’d like to separately discuss some of the individual digestive enzymes so you can have a better understanding of the role each of these play in digestion:
Digestive Enzymes Involved In Protein Digestion:
I’m not going to list all of the enzymes that are involves in protein digestion, but only some of the more commonly known ones. Digestive enzymes that break down proteins into amino acids are also known as proteases, or proteolytic enzymes. While proteolytic enzymes can be taken with meals to help break down proteins, they can also serve other purposes. For example, taking proteolytic enzymes in between meals can help to reduce inflammation and dissolve biofilm.
Pepsin. Pepsin is an enzyme that is formed by pepsinogen, which is released by the chief cells in the stomach, and helps to break down protein into amino acids. Hydrochloric acid is released by the parietal cells, and helps to convert pepsinogen into pepsin.
Trypsin. Trypsin helps to break down proteins into smaller peptides, which in turn are further broken down. Unlike pepsin, trypsin works at a higher pH, usually between 7.5 to 8.5.
Chymotrypsin. Chymotrypsin is another proteolytic enzyme synthesized by the pancreas.
Bromelain. This is extracted from pineapple stems and juice, and helps to break down protein into amino acids.
Papain. This enzyme is derived from papaya, and helps with the digestion of proteins.
Serratiopeptidase. This is also known as serrapeptase, and this proteolytic enzyme is commonly recommended for it’s anti-inflammatory, anti-edemic and analgesic effects (1).
Hydrochloric Acid. Hydrochloric acid (HCL) isn’t a digestive enzyme, but it is involved in protein digestion. HCL is produced by the parietal cells, which are one of the types of cells located in the stomach. HCL activates pepsinogen into pepsin, which helps with the breakdown of proteins. However, HCL also assists in the eradication of pathogens that are present in the food you eat.
Digestive Enzymes Involved In Fat Digestion:
The digestion of fats mainly takes place in the small intestine, although some of it begins in the mouth. Fat digestion involves the following enzymes and compounds:
Lingual lipase. This digestive enzyme is found in the mouth, and is what starts the process of fat breakdown. So for example, if you eat an avocado the first enzyme that is released which is involved in fat breakdown is lingual lipase.
Pancreatic lipase. This digestive enzyme is of course secreted by the pancreas, and it also aids in the breakdown of lipids and fats. Problems with lipase activity can lead to the impaired absorption of fat-soluble nutrients, which includes vitamins A, D, E, K, along with essential fatty acids.
Bile salts. While bile salts aren’t enzymes, they are very important when it comes to breaking down fats in a process known as emulsification. If someone has a bile metabolism problem then this in turn can affect the breakdown of fats, although one can supplement with bile salts. For more information I would read a blog post I’ve written entitled “The Importance of Bile In Thyroid Health“.
Digestive Enzymes Involved In Carbohydrate Digestion:
Most of the digestion of carbohydrates takes place in the small intestine, although as I mentioned earlier, it begins in the mouth with the help of salivary amylase. Carbohydrate digestion involves the following enzymes:
Amylase. Once again, this is a digestive enzyme that is present in the saliva, and helps to initiate the digestive process. It is produced not only by the salivary glands, but by the pancreas as well. High levels of amylase in the blood can indicate pancreatitis (inflammation of the pancreas), although there can be other causes.
Lactase. This enzyme is located in the brush border of the small intestine, and it breaks down lactose, which is a sugar found in dairy products. Many people have a lactose intolerance, which involves a deficiency of lactase.
Sucrase. This is a digestive enzyme that is secreted by the small intestine. This enzyme breaks down sucrose to fructose and glucose.
Alpha-galactosidase. This is a digestive enzyme located in the brush border of the small intestine. It breaks down starch and disaccharides to glucose.
Hormones Involved In The Digestive Process
Most people don’t realize that certain hormones are important for optimal digestive health, and so I wanted to briefly mention some of these:
Gastrin. This hormone is located in the stomach and is involved in the stimulation of both pepsinogen and hydrochloric acid. When you eat, the food is what in turn stimulates the secretion of gastrin.
Secretin. This hormone is located in the small intestine, and is involved in the secretion of sodium bicarbonate and bile.
Cholecystokinin. This hormone is located in the small intestine and is involved in the release of digestive enzymes and the emptying of bile.
Gastric inhibitory peptide. This hormone is in the small intestine and decreases the churning of the stomach, which in turn slows down the emptying of the stomach.
Motilin. This hormone is in the small intestine and is involved in gastrointestinal motility and the production of pepsin.
Three Risks of Having Low Digestive Enzymes and HCL
There are numerous risk factors for someone who produces lower levels of digestive enzymes and/or hydrochloric acid, or has problems with bile metabolism, but I’m going to focus on three of these risk factors here:
1. Nutrient deficiencies. If someone has low levels of these digestive enzymes and/or HCL then of course the food won’t be properly digested, and this can lead to nutrient deficiencies. These nutrient deficiencies in turn can lead to a compromised immune system, affect the metabolism of hormones and neurotransmitters, which use these nutrients as cofactors, and this can obviously lead to a lot of health issues. I talk a lot about the importance of eating whole foods, but if you have problems manufacturing digestive enzymes and/or have low HCL levels then you won’t be getting optimal benefits from the food you eat, and it can lead to other health issues. Some of the more common nutrient deficiencies which can have a negative effect on thyroid health include iodine, selenium, zinc, iron, vitamin A, and tyrosine.
2. Food sensitivities. Undigested food residues can lead to food sensitivities. As I mentioned earlier in this article, many, if not all people with autoimmune conditions such as Graves’ Disease and Hashimoto’s have an increase in intestinal permeability, which is also known as a leaky gut. And if someone has a leaky gut, undigested proteins can pass through the intestinal barrier into the bloodstream, which in turn can cause an immune system response. This can not only be a potential trigger of autoimmunity, but it can also be a reason why someone tests positive for a lot of food sensitivities when doing an IgG food sensitivity panel.
3. Bacterial and yeast overgrowth. This is especially common with low levels of HCL, as this isn’t only important for proper digestion of nutrients, but it’s also necessary for keeping the yeast and bacteria in check. I’m not just talking about harmful yeast and bacteria, as we need to realize that having yeast such as Candida is normal, but it’s the overgrowth of Candida that’s problematic, and one of the potential causes is low levels of HCL. This is also one potential cause of small intestinal bacterial overgrowth, although low digestive enzymes and bile salts can also lead to bacterial overgrowth. And while having a Candida infection or SIBO might not directly trigger thyroid autoimmunity, these can potentially cause a leaky gut, which in turn can make someone more susceptible to developing an autoimmune thyroid condition. Low HCL levels are much more common with hypothyroidism, but it can also affect those with hyperthyroidism and Graves’ Disease as well.
Testing For Digestive Enzymes, HCL, and Bile Salts
Pancreatic Elastase. Pancreatic elastase is a protein-digesting enzyme that is exclusively produced by the pancreas, and as a result, it serves as a marker of pancreatic function. In other words, if someone obtains a stool panel which shows a low or depressed pancreatic elastase, then this is a sign of pancreatic insufficiency. As a result, if someone is experiencing symptoms such as diarrhea, weight loss, undigested food in the stool, and/or abdominal pain, then it might be a good idea to get this tested.
Chymotrypsin. Although pancreatic elastase seems to be the preferred method of determining if someone has pancreatic insufficiency, some labs will test chymotrypsin through the stool.
Lipase. Lipase can be measured in the blood. Low levels can be a sign of pancreatic insufficiency, whereas elevated levels are usually associated with acute pancreatitis.
Amylase. Just as the case with lipase, low levels of amylase can be a sign of pancreatic insufficiency, whereas elevated levels are usually associated with acute pancreatitis. In fact, approximately 80% of those who have acute pancreatitis will have increased serum amylase within 24 hours.
Hydrochloric acid. The Heidelberg Stomach Acid Test can help to determine if someone has hypochlorydria, which is low stomach acid. This involves the patient swallowing a capsule which includes a pH monitoring device, and this measures the levels of stomach acid while the person drinks a baking soda solution. However, getting a doctor to order this test isn’t always easy. Many natural healthcare professionals will recommend a betaine HCL challenge test, which involves taking a capsule of betaine HCL with pepsin, along with a high protein meal, and if someone doesn’t notice any symptoms (i.e. heartburn) then this is usually an indication that the person has low stomach acid. On the other hand, if the person experiences heartburn then this is a sign that they have sufficient levels of stomach acid.
Bile acids. The Comprehensive Digestive Stool Analysis (CDSA) 2.0 by Genova Diagnostics has a few markers which relate to bile metabolism. This tests for the bile acids, including lithocholic acid. Some conventional labs also test for bile acids, and elevated levels are frequently an indication of problems with bile metabolism, which can increase one’s risk of developing gallstones, along with certain types of cancers. Earlier I mentioned “bile salts”, and if you’re wondering what the difference is between bile acids and bile salts, bile acids are synthesized by the liver, and they combine with either taurine or glycine to form bile salts. These bile salts are then secreted into the small intestine, where they form secondary bile acids, known as deoxycholic and lithocholic acid.
The Units Of Digestive Enzymes Can Be Confusing
I’m not going to get into much detail here, as this topic alone is deserving of a separate article. Whereas the units of measurement of most nutritional supplements are fairly straightforward, it can be pretty complex when it comes to digestive enzymes. The reason for this is because different types of digestive enzymes have different units. For example, I looked at a digestive enzyme supplement with many different enzymes, and here are some of the different units:
Digestive Enzyme Units Used
Amylase BAU (bacterial amylase unit)
Lipase FIPU (Fungi Lipase-International unit)
Protease HUT (hemoglobin unit on the tyrosine basis)
Lactase ALU (acid lactase unit)
Cellulase CU (cellulase unit)
Beta-Glucanase BGU (beta-glucanase unit)
There are about another dozen different units I haven’t listed here. I would rely on the natural healthcare professional you’re working with when choosing a digestive enzyme supplement. And of course most of the good quality supplement companies have digestive enzymes with sufficient amounts of each digestive enzyme. Just remember that everyone is different, and some people will need to take more than the suggesting serving size indicated on the label.
Plant vs. Animal Sources of Digestive Enzymes
Is it best to consume plant or animal sources of digestive enzymes? I think both of these can be effective, and I commonly recommend a vegetarian-based digestive enzyme to my patients. Bromelain and papain are two of the more well-known plant-based enzymes, and digestive enzymes can also be derived from microbial sources, such as fungal organisms (i.e. Aspergillus). In fact, many companies that sell vegetarian-based digestive enzymes use an Aspergillus fungal species as the source of their enzymes. Pancreatin is an example of digestive enzyme derived from an animal source (i.e. a porcine or bovine pancreas).
What’s The Deal With Dipeptidyl Peptidase-4?
Dipeptidyl peptidase-4, also known as DPP-4, is a type of digestive enzyme that can break down gluten proteins. As a result, numerous supplement companies have created products which include DPP-4. However, while taking a supplement with DPP-4 can be used to help with accidental exposure to gluten (i.e. when eating out), keep in mind that this enzyme won’t be able to break down all of the gluten proteins. As a result, if you are trying to follow a strict gluten free diet, taking a digestive enzyme with DPP-4 won’t completely neutralize the negative effects of gluten.
Should YOU Take Any Supplements For Digestion?
As for whether or not you should take supplements to help aid in digestion, it depends on the situation. In most cases I will recommend for my patients to take digestive enzymes as a form of general digestive support, and there are times when I’ll recommend for my patients to take betaine HCL or bile salts. For example, if someone experiences a sense of fullness right after eating on a regular basis then this is an indication of low stomach acid, and thus the person might want to consider taking betaine HCL. On the other hand, if someone experiences a sense of fullness a few hours after eating on a regular basis then this usually indicates low digestive enzymes. However, the lack of these symptoms doesn’t necessarily mean that someone can’t benefit from taking digestive enzymes or betaine HCL. If someone has problems digesting fat, which is usually indicated by digestive symptoms after eating fats and/or floating stools, and if taking a digestive enzyme with lipase isn’t helping, then they might benefit from taking bile salts or ox bile.
So hopefully you have a better understanding of the importance of digestive enzymes, HCL, and bile salts. Digestive enzymes are important for the breakdown of carbohydrates, protein, and fat. HCL is specific for breaking down protein, while bile salts are necessary for the emulsification of fats. Having a deficiency in any of these can not only result in malabsorption and resulting nutrient deficiencies, but it can also set the stage for food sensitivities, along with bacterial and yeast overgrowth. Although testing is available to determine if someone has a deficiency of enzymes, HCL, and bile salts, many times you can tell if someone has a deficiency based on the symptoms they are experiencing.