By John Laznovsky
The Wolf of Wellness
8/27/24
Addressing Myths and Misconceptions:
Myth- “Humans digest plants better than meat.”
We’ve heard this myth going around for some time and wanted to address why this is inaccurate from a scientific point of view.
Protein Digestion:
Technically all digestion begins in the mouth with mechanical chewing but the chemical digestion of proteins begins in the stomach. The stomach is a highly acidic environment, with an average pH of around 2 to 2.5. This is due to the presence of hydrochloric acid, which is released by the parietal cells of the stomach. In addition to the acidic environment, the gastric chief cells of the stomach release pepsinogen (a zymogen or inactive form of pepsin), which is eventually converted to pepsin.
Pepsin is a type of protease. Proteases help digest proteins by breaking the peptide bonds, a type of bond that links carbon # 1 from one amino acid to nitrogen # 2 of another. This takes place through hydrolysis, which is the breaking of a bond via the addition of water, so proteins can be broken down into their smaller counter parts, amino acids.
The acidic environment of the stomach kicks off the major digestive processes so proteins become denatured and break apart (this means tertiary and quaternary structures of proteins begin to unfold and unravel). While this is taking place, pepsin will be also be breaking peptide bonds to produce amino acids. Eventually, the partially digested protein food stuffs (a mixture of unraveled proteins and amino acids) make their way into the small intestine.
Once in the small intestine, more proteases are released into the duodenum by acinar cells (exocrine) in the pancreas in the form of zymogens. Proteases released by the pancreas include trypsinogen, chymotrypsinogen, proelastase and procarboxypeptidase. These zymogens are eventually converted to their active forms, which are trypsin, chymotrypsin, elastase and carboxypeptidases, respectively. Trypsin, chymotrypsin, and elastase are all considered endopeptidases, which means they hydrolyze (break) peptide bonds on the interior of a protein. While carboxypeptidases A and B are considered exopeptidases, which means they break bonds at the end of proteins. Elastase is also noted for its ability to break bonds and assist with the digestion of connective tissue that is found in meat. All protein absorption takes place in the small intestine.
As you can see, the body has very efficient mechanisms in place for digesting meat, including a highly acidic environment and a diverse array of enzymes for digesting all parts of meat. In fact, studies have shown 95% efficiency for digesting and absorbing meat, which is considered highly efficient. (1)
Plant Digestion in General:
Fruits, vegetables and grains are made up of different varying components, such as plant fibers (cellulose), plant proteins, sugars (fructose, glucose, sucrose etc.) and starches from rice, potatoes, barley etc. It is important to note that all plants contain cellulose, especially in their cell wall, which is an indigestible form of plant fiber for humans. Plant proteins, sugars and some cooked starches are the most easily digested parts of the plant. It should also be noted that raw, as in uncooked starch, is very poorly digested. (2)
Starch chemical digestion technically begins in the mouth due to the release of salivary amylase but very minimal digestion actually takes place in the mouth since it passes quickly to the stomach via the esophagus, after chewing. The stomach doesn’t release any enzymes related to starch digestion, therefore, the majority of starch digestion takes place in the small intestine. The main enzyme for digesting carbohydrates is amylase, which is released into the small intestine via the acinar cells of the pancreas.
Interestingly, amylase is only capable of breaking alpha 1,4 and 1,6 glycosidic bonds in starches. Thus, not all components of starch can be digested and some starches are resistant, meaning they can not be digested. For example, cellulose contains beta 1,4 glycosidic bonds and can not be broken down by amylase. (3) Therefore, cellulose is considered indigestible for humans. Remember, all plant foods contain cellulose in varying amounts, which means all plant foods have a certain portion that can not be digested. Further, some plants contain large portions of cellulose and/or resistant starch, making their digestibility very poor.
However, ruminants and are capable of breaking beta 1,4 glycosidic bonds and digesting cellulose. This is because they contain special bacteria in their intestines, such as fibrobacter succinogenes, ruminococcus flavefaciens, and ruminococcus albus. Some termites also contain special bacteria and protists that help them digest cellulose.
Plant Protein Vs. Animal Protein:
The chemical digestion of plant proteins begins in the stomach and finishes in the small intestine, exactly as animal proteins are digested, and the same enzymes are involved. Except, there are some major differences between plant protein content versus animal protein content and how efficiently they are digested.
Overall, plant proteins have less of an anabolic effect, a lower essential amino acid profile, a lower protein content per serving and lower digestibility compared to animal proteins. (1, 4, 5, 6, 7, 8) This means that plant proteins are less likely to be used in muscle protein synthesis compared to animal proteins.
In terms of digestibility, a direct comparison between animal protein and plant shows that plant protein has 75-80% digestibility compared to animal protein, which has 90-95% digestibility. (5) Researchers attribute the lower digestibility of plant proteins to plant fibers, such as cellulose and resistant starches. These plant fibers can slow digestion and even inhibit nutrient absorption.
It should be noted that some plant proteins, such as soy and pea protein are considered more digestible. However, this requires the soy and pea plants to be processed so that the proteins are isolated and typically heated to make them more digestible. Without processing, the proteins in pea and soy are not as digestible, thus, peas and soybeans are not naturally as digestible as meat. Additionally, soybeans and peas are considered to be high FODMAP foods, while soy also contains phytoestrogens.
Further, studies have revealed that some participants who switched from an animal based protein diet to a plant based protein diet complained of gastrointestinal issues. (7) This was most likely due to the high fiber, FODMAP and anti-nutrient content contained in plant foods. (FODMAPS, Phytoestrogens and Anti-nutrients are discussed below)
Bioavailability of Nutrients in Animal-based Foods Vs. Plant-based Foods:
In general, an overview of studies showed that vitamins from animal-based foods are more bioavailable than vitamins from plant-based foods. Further, these studies concluded that foods derived from animals are “the almost exclusive natural sources of dietary vitamin B-12 (65% bioavailable) and preformed vitamin A retinol (74% bioavailable), and contain highly bioavailable biotin (89%), folate (67%), niacin (67%), pantothenic acid (80%), riboflavin (61%), thiamin (82%), and vitamin B-6 (83%).” (9)
Anti-nutrients, Complex Proteins, FODMAPS and Hormone Disrupting Compounds in Plants:
Many plant-based foods contain anti-nutrients, such as oxalic acid, phytic acid and lectins, as well as hormone disrupting compounds such as phytoestrogens. These anti-nutrients, especially oxalic acid can interfere with nutrient absorption, trigger arthritic flare ups and cause digestive inflammation, weight gain, IBS, constipation, skin rashes, vascular inflammation and kidney stones. (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
Oxalic acid is a plant toxin that certain minerals, such as calcium, have an affinity for. These minerals will bind to oxalic acid, forming an oxalate crystal. In the case of calcium, calcium oxalate crystals are formed when bound to oxalic acid. The most common type of kidney stone is calcium oxalate.
Oxalates can produce oxidative stress in the tissues and vessels, and have therefore been associated with premature aging, and an increased risk of cancer and cardiovascular disease. In fact, one study showed that the oxidative stress from oxalates may induce premature senescence (premature aging) by shortening telomeres! (20) In case you don’t know, cellular senescence is the age associated arrest of a cell. Senescent cells begin to accumulate as we age. Researchers have nicknamed senescent cells, “zombie cells” because they no longer function properly and can disrupt normal cellular processes. Basically, the more zombie cells we accumulate, the more we age.
Grains tend to be high in phytic acid and saponins, both of which can interfere with the absorption of important minerals, such as iron, zinc, magnesium, and calcium. Phytic acid chelates with these minerals, pulling them from the body. This could lead to mineral deficiencies over time. They also contain complex proteins and fructans (non-digestible carbohydrates) that are difficult for many people to digest and may trigger immunoreactivity. Recent studies have shown that the nutritional quality of grains has declined over the last 166 years, with grains today containing higher amounts of starches and lower mineral contents. (22, 23, 30, 31, 32)
FODMAPs, which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, have been known to cause digestive symptoms, such as IBS, diarrhea, bloating and cramping. These are short-chain carbohydrates (sugars) that are poorly absorbed in the small intestine, and eventually make their way to the large intestine, where they ferment and can cause a host of issues.
Nuts, seeds and legumes contain hormone disrupting compounds such as phytoestrogens (from lignans) and sex hormone binding globulins (SHBG). These compounds can interfere with important hormones, such as testosterone and estrogen, which can cause a host of issues in the body. (26, 27, 28, 29) In addition, many people can be sensitive/ allergic to nuts and seeds and have no idea. This would also disrupt digestion.
Meat does not contain complex proteins, FODMAPs, anti-nutrients and hormone disrupting compounds like plants do.
If you’re looking for help with your diet plan, check out our Anti-Inflammatory Diet for Overall Health and Weight Loss at:
https://wolfmoonwellness.com/nutrition-plan/
We deep dive into the science behind the way human beings are meant to eat and offer numerous resources to back up every suggestion. Additionally, we offer specific food lists that you can easily create an entire meal plan from, example meals, portion size recommendations, fasting strategies, exercise recommendations and extra strategies for body fat loss.
“Then Why Does It Feel Like I Have a Hard Time Digesting Meat?”
This is a question we’ve been asked throughout the years so we want to take the time to address it.
There are many possible reasons why you could feel like you’re having a hard time digesting meat but we want to address the major possibilities:
1. Quality of Meat:
The first possibility is the quality of meat you are eating. Are you eating 100% grass-fed meat that is free from antibiotics and preservatives? If not, you may want to try a higher quality meat and see how you do. If you are eating higher quality and still feel like you’re having trouble, refer to the possibilities below.
2. Sauces, Herbs and Spices:
“I need flavor!” Gourmet meals with different creams, sauces, herbs and spices are very popular these days. We understand that people like a little flavor with their food, unfortunately, indigestion and reflux are commonly caused by sauces, herbs, pepper and spices. In fact, we’ve heard of several cases where people originally suspected meat as a culprit for indigestion, but the real culprit turned out to be the preservatives, herbs, spices and sauces used to flavor the meat.
You could also be sensitive/ allergic to any of the herbs, pepper and spices you are using and have no idea. This would further impact your ability to digest the meat in your gourmet dish. In addition, store bought sauces, creams and garnishes usually contain questionable ingredients. Even home-made recipes typically call for questionable ingredients.
3. If You Don’t Use It, You Lose It:
Many people coming from a vegan/ vegetarian diet are switching back to eating meat. Some of these people also complain that they are having a hard time digesting meat. Vegan/ vegetarian diets are typically lower in total protein content and plants don’t contain connective tissue. The body will adapt to whatever circumstances are present. Diets higher in protein/ phosphorus have been associated with greater stomach acid production, while plant based diets are associated with lower stomach acid production. (33, 34) Therefore, it’s possible that when switching from a plant based diet to eating meat, the body may not be used to secreting enough stomach acid to digest larger amounts of protein. Remember, stomach acid played a crucial role in the chemical digestion of proteins.
In addition, the digestive enzymes needed to fully digest proteins work on feedback mechanisms. This means when larger amounts of protein and connective tissue are present, a positive feedback mechanism is present and digestive enzymes will continually be released until they are no longer needed. A diet lower in protein and connective tissue, such as a plant based diet, does not require the continuous release of enzymes for digesting meat and connective tissue. Thus, lower levels of enzymes are produced and released over time. The body may become less efficient over time at producing and releasing enzymes for digesting the larger amounts of protein and connective tissue in meat. Indeed, studies have shown that people who follow plant-based diets produce less pancreatic proteases. (35) This doesn’t mean you can’t become more efficient at digesting meat. It may take some time and a few interventions, we’ll discuss strategies below.
4. Directly Addressing The Claim That Plants Feel Easier To Digest Than Meat:
So why do some people claim that it feels easier to digest plants versus meat? We feel there is a pretty simple explanation for this, and after reading this article, it should make sense to you. As previously mentioned, plants contain fibers, such as cellulose and resistant starches. These fibers can not be digested, thus, plants that are higher in fiber tend to pass right through the digestive system, especially the stomach, without being properly digested. This could lead people to the false notion that they are digesting the plants better when in reality, they probably aren’t digesting them well at all. Further, these plant fibers will make their way to the large intestine without being digested and can cause gas, bloating and cramping hours later. Since this is taking place hours later, people aren’t making that connection that the plants were more difficult to digest.
As previously mentioned, proper chemical digestion of meat relies on stomach acid production. Thus, meat needs to spend a longer time in the stomach than plant foods do. People may notice in the short term that the meat stays in the stomach longer and assume it’s because they are having a harder time digesting it. However, based on the the evidence presented throughout this article, you should now see that meat is in fact more digestible than plants.
5. The Power of The Mind:
The final possibility we would like to discuss is the influence of the mind on the body, or the mind/body connection. Don’t ever underestimate the power of the mind. If you convince yourself that meat is bad, more difficult to digest, or makes you feel sick, then this will most likely be true for you. In this case, the best thing you can do is try to keep an open mind and put aside any preconceived notions about eating meat.
Our recommendation for optimizing the digestion of meat:
Go for higher quality 100% grass-fed meat and to keep it as simple as possible. Just use a high quality salt that is low in heavy metals, such as Maldon, Jacobsen, or Icelandic sea salt for seasoning, nothing else. Avoid sauces, herbs, spices and creams.
In addition, digestive enzymes, such as proteases, apple cider vinegar, and salt may help to improve digestion of meat and increase stomach acid production. Finally, give it some time. Your body may just need some time to adjust to eating meat.
Conclusions:
According to the evidence, meat is more digestible, has a higher essential amino acid and relative protein content, contains more bioavailable nutrients, as well as exclusive nutrients, and does not contain anti-nutrients that are known to cause inflammation and disrupt digestion. Plants contain fibers such as cellulose and resistant starches that can not be digested. These fibers tend to slow or disrupt the digestion of other nutrients and may irritate the digestive system. Plants also contain complex proteins that are difficult to digest, and anti-nutrients that can cause inflammation and negatively impact digestive processes. Therefore, meat is better tolerated and superior to plants when it comes to digestibility and bioavailability of nutrients.
Plant-based diets may lead to lower overall stomach acid production and release of digestive enzymes, such as proteases. Adjusting from a plant-based diet to a diet that includes meat may take some time and certain strategies may need to be adopted to ameliorate the process.
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