How Understanding Amino Acids Digestion Can Definitely Improve Your Health

“You are what you eat!” The huge words from a colorful poster in the cafeteria of my elementary school keep coming to mind. Fifty years ago, as a child, and being very literal, I thought I would turn into a cow, a fish, or a sprig of broccoli, as pictured on the poster if I ate those things. Those who are less literal might still think they have chicken, fish, egg, or milk proteins in their bodies – This is NOT the case! The digestive system takes every single protein you eat, completely digests it into individual amino acids, and then allows you to use them to make your own proteins.

Proteins are long chains of amino acids. It is not protein that we need, it’s amino acids. We make our own proteins out of the amino acids we absorb. Therefore, when we eat protein, it is essential that we digest it completely, and absorb the amino acids.

DIGESTION OF PROTEINS

Have you ever wondered why eggs get hard when you cook them?[i]

Albumen is the white part of the egg. It is made of a bunch of individual balls of protein suspended in water. Heat causes the little balls of protein to unravel, and then the strings of protein wind around each other like a hairball, and start sticking to each other, called crosslinking. When they are all stuck together, they can no longer move separately, so they become a solid, instead of a liquid.

This same process goes on in your stomach.[ii] The acid in your stomach acts on protein like heat, causing the little protein molecules that you just broke up by chewing to unravel and open up, but then, instead of allowing them to stick together, the stomach has ENZYMES that cut them into pieces as they unwind, so they don’t harden. Then, they go down into the small intestine where pancreatic enzymes break down the short protein chains, called peptides, into individual amino acids.

These amino acids are absorbed through the intestine, going into the blood so every cell in the body can use them to make proteins and other things. Thus, EVERY ONE of the proteins in your body is made by you. They are each unique to you from your hair to your toenails. You have no proteins that belong to or came from anyone, or anything else. This is important because your immune system uses the uniqueness of your proteins to identify you as you.

To properly digest proteins, the stomach must produce acid – a lot of acid. The pH inside your stomach is enough to burn you severely if it spills on you.[iii] It must denature proteins, and your skin is made of protein. This acid along with enzymes is required to digest the proteins you eat.

We make acid and digestive enzymes according to what we eat. Eating protein causes the production of a hormone called “gastrin” which tells the stomach to make more acid so the proteins can be digested. Eating sugar, on the other hand, causes the production of a hormone called GIP (Gastric Inhibitory Polypeptide) which stops the stomach from making acid and enzymes. So, if we eat only protein in a meal, we will digest it easily, but if we eat sugar with the protein, it may prevent the full digestion of proteins. There are many proteins in a modern diet that are mixed with sugar. For example:

• Flavored yogurt
• Peanut butter with honey
• Ketchup on hamburgers
• Chocolate milk
• BBQ sauce on meat
• Bread and cheese
• Cinnamon rolls

These all contain a mixture of protein and sugar which may impair the digestion of the protein. “What about cinnamon rolls?” you ask. There is gluten in the cinnamon roll that requires a high level of acid to digest. Many people have celiac disease because of eating sugar with wheat protein. Individuals will respond differently, it is just something to keep in mind, especially if you lack amino acids.

ABSORPTION OF AMINO ACIDS[iv]

Amino acids must be actively absorbed in the intestines. There are multiple mechanisms for absorption, and therefore multiple things that can go wrong, preventing absorption and causing deficiencies.

• Lack of Digestive Enzymes: digestive enzymes are essential for breaking proteins down into amino acids.
• The wrong Gastrointestinal pH: Different enzymes require specific pH levels to function optimally. For instance, pepsin in the stomach needs a highly acidic environment (pH 1.5-3.5), whereas enzymes in the small intestine, such as trypsin and chymotrypsin, require a slightly alkaline pH (around 7-8).
• Poor Gastrointestinal Health: Conditions such as celiac disease, “leaky gut,” Crohn’s disease, or other inflammatory bowel diseases can damage the intestinal lining, leading to malabsorption of amino acids.
• Presence of Antinutrients: Phytates (found in grains and legumes), lectins (from seeds and vegetables), and tannins (found in some teas and fruits) can bind amino acids and make them less available for absorption.
• Diet Composition: dietary components can hinder amino acid absorption. For example, sugar can compete with amino acid absorption, as can antacids and calcium supplements.
• Transport Mechanisms: Some amino acids share the same transport channels across the intestinal membrane. For example, leucine, isoleucine, valine, methionine, and threonine all share transporter systems, so a high concentration of one can limit the absorption of the others.
• Meal Timing: eating late at night can prevent digestion and absorption of amino acids.
• Medications: acid reducers for acid reflux can decrease both the stomach acid and enzymes that digest proteins.

The absorption of amino acids is complex, requiring multiple mechanisms working together to make sure you have enough of each. Your cells can make some of them, but some amino acids are essential.

ESSENTIAL AMINO ACIDS[v]

Nine amino acids are called “essential” because you cannot make them in your body. This means that the only way to get these is from your diet. All are needed to make most proteins, but each has a special function:

1. Histidine: growth and repair of tissues, production of blood cells, and helps protect nerve cells
2. Isoleucine: muscle metabolism, immune function, hemoglobin production, and energy regulation
3. Leucine: protein synthesis, muscle repair, and regulation of blood sugar levels; stimulates growth hormone production
4. Lysine: growth, tissue repair, hormone production, enzymes, and antibodies
5. Methionine: energy metabolism and detoxification; tissue growth and the absorption of zinc and selenium
6. Phenylalanine: Brain function, makes tyrosine, dopamine, epinephrine, norepinephrine and thyroid; also required for enzymes
7. Threonine: collagen and elastin, and nervous system function
8. Tryptophan: maintain proper nitrogen balance and serotonin
9. Valine: muscle growth and regeneration, energy production

If you are missing any of the essential amino acids, you can get deficiency diseases of all kinds, as you can see from their function. You want to be sure you get a good balance of these from your food.

AMINO ACIDS IN DIFFERENT FOODS

In the Old Testament, the prophet Daniel and his companions were offered a place in the king’s court but were required to eat the king’s meat. They proposed a scientific test to see if they could fare well on “pulse” a mixture of grains and legumes (a vegan diet). They did fine.

All food has protein because life requires protein to function. Plants make lots of protein. However, the types and amounts of plant proteins are different so they have a different amino acid profile. They are also digested differently.

Animal proteins, including meat, are considered complete proteins because they contain all the essential amino acids in proportions suitable for human needs.[vi] The structure of meat protein is typically more accessible for digestive enzymes to break down compared to many plant proteins. This is partly due to the fibrous nature of plant cell walls and the complex structures in some plant proteins, which can make them less accessible to digestive enzymes. Also, plants often contain anti-nutritional factors such as phytates, tannins, lectins, and protease inhibitors, which can interfere with protein digestion and absorption.

Moreover, plant proteins often lack one or more essential amino acids or have them in lower quantities, especially if the food is processed. White flour, white rice, and other processing of plant foods remove much of the protein. It is possible to obtain sufficient and high-quality protein from a well-planned plant-based diet by choosing a wide variety of less processed, whole foods. For example, effectively combining different plant protein sources, like beans and brown rice, can provide a complete amino acid profile.[vii]

INSULIN RESISTANCE AND AMINO ACIDS:[viii]

We have already talked about how the digestion of proteins can be inhibited by sugar. But there is more. Insulin resistance also has a large effect on amino acids. Insulin stimulates the uptake of amino acids and the production of proteins. Insulin is a growth hormone. So, when people have insulin resistance these mechanisms stop working. Not only is glucose blocked from getting into cells, it also prevents amino acid transport. The amino acids most affected are those that are most important for energy and growth:

• Leucine
• Isoleucine
• Valine
• Phenylalanine
• Tryptophan
• Tyrosine
• Methionine
• Serine
• Proline
• Glutamine

Deficiencies in these amino acids will slow healing, cause depression and anxiety, can lead to Parkinson’s Disease, Alzheimer’s Disease, and immune dysfunction. Some of the deficiencies also lead to low thyroid, fatigue, weakness, and lack of energy production. People with insulin resistance are often found to be deficient in one or more of these amino acids and are told to take supplements.

AMINO ACID SUPPLEMENTATION

It is common today for physicians to prescribe amino acids for all sorts of health issues, such as:

• Lysine to prevent herpes.[ix]
• Tryptophan for depression and anxiety.[x]
• Cysteine (NAC) for liver detox.[xi]
• Arginine for hypertension.[xii]
• BCAA (branched-chain amino acids: Leucine, Isoleucine, Valine) to build muscle.[xiii]
• Tyrosine for low thyroid.[xiv]
• Glutamine for intestinal problems.[xv]

The problem with this, however, is that these amino acids compete for absorption with other amino acids. We need all the amino acids, not just some of them. Taking large amounts of one may change the balance of amino acids in the body. For example, taking extra lysine lowers arginine, which blocks the herpes virus from replicating. However, less arginine lowers nitric oxide which is needed to relax blood vessels, causing high blood pressure.

Amino acid supplementation is sometimes needed for a specific purpose, but it is best to have a balance of all amino acids. This balance almost always is a matter of digesting and absorbing the protein you eat. For this reason, before taking supplements, it is better to make sure your digestion, absorption, and metabolism of proteins are working properly.

Those who may have genetic or other metabolic dysfunctions should test amino acids in both urine and blood. The urine shows what you are excreting from your kidneys, and the blood shows the level of amino acids you have available to make proteins. These tests will determine if you need to supplement one or more amino acids.

MORE IS NOT BETTER

We have a persistent concept in modern society that if some is good, then more is better. If I need all the amino acids, why don’t I just take protein supplements all the time? This can be counter-productive, especially for those who have insulin resistance. Remember that insulin resistance prevents amino acids from getting into the body, into the brain, and into cells. That creates an imbalance. Some get in, but some don’t. This creates a bottleneck of amino acids that prevent proteins from being made. Moreover, there are excessive amino acids in the blood that cannot get into cells, making them toxic. This is like having excess glucose in diabetes.

For example, high levels of amino acids block an enzyme called the mammalian Target Of Rapamycin (mTOR) pathway, which is crucial for cell growth and protein synthesis, causing muscle wasting, fatigue, and weakness. The body becomes resistant to this enzyme as it is resistant to insulin. So, amino acid supplements are not for everyone.

WHO NEEDS AMINO ACID SUPPLEMENTS?

• Low glutathione – There are many who have genetic defects in the sulfation (sulfur) pathways, requiring supplements of methionine (SAMe) and/or cysteine (NAC).
• Connective tissue disorders like Ehlers-Danlos Syndrome (EDS) often need collagen peptides. This can also be done with bone broth.
• Abnormal neurotransmitters – those who have deficiencies in enzymes to make dopamine, epinephrine, and norepinephrine or thyroid hormone, may need a tyrosine supplement.
• Low Digestive enzymes – those who are deficient in enzymes, may take an enzyme supplement, or sometimes a comprehensive essential amino acid supplement.
• Achlorhydria – low stomach acid production can be helped with Betaine HCL and Pepsin with meals to get proper digestion of proteins.

PROGRAM TO IMPROVE DIGESTION AND ABSORPTION OF AMINO ACIDS:

It is possible, even preferable, to get all your amino acids from your food. There is no lack of protein or amino acids in a diet that has a variety of foods. The problem is usually from digestion and absorption of these nutrients. This is the way to improve your digestion of proteins:

• Do not mix sugar and protein in the same meal.
• Prevent insulin resistance; avoid sugar and artificial sweeteners.
• Eat a variety of foods.
• Avoid snacks. Leave at least 5 hours between meals to reset the stomach and pancreas.
• Proper food preparation such as soaking, sprouting, fermenting, or cooking can reduce the levels of antinutrients.
• Supplements of certain vitamins and minerals (like magnesium, vitamin C, and vitamin B6) can aid in the metabolism and absorption of amino acids.
• Avoid foods to which you are sensitive.
• Don’t take “acid blockers.” Instead, stop eating before 6 pm.

After you have done all you can, and you still have issues with a lack of one or more amino acids, it would be a good idea to take a supplement. These should be taken without food, so they do not inhibit your ability to absorb other amino acids.

The key to amino acids is balance. Balance is best achieved by digesting your proteins and absorbing all the amino acids. Your metabolism is made to use all the amino acids, so don’t get over-focused on one, or just a few. Though you may not turn into an egg or a cucumber, your diet will determine which amino acids you have, and thus which proteins you are able to make. A good balance brings health and vitality to your body and brain!

 

 

 

 

 

 

Sources:

[i] https://spie.org/images/Graphics/Newsroom/Imported-2012/004149/004149_10_fig1.jpg

[ii] https://open.oregonstate.education/aandp/chapter/23-4-the-stomach/

[iii] https://sciencenotes.org/what-is-the-ph-of-the-stomach/

[iv] https://www.sciencedirect.com/science/article/pii/S2667268521000139

[v] https://en.wikipedia.org/wiki/Essential_amino_acid

[vi] https://www.foodfact.info/food/beef/amino-acids/

[vii] https://www.verywellfit.com/vegan-protein-combinations-2506396

[viii] https://diabetesjournals.org/diabetes/article/68/6/1353/39714/Nine-Amino-Acids-Are-Associated-With-Decreased

[ix] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419779/

[x] https://www.mayoclinic.org/drugs-supplements/tryptophan-oral-route/proper-use/drg-20064453

[xi] https://www.ncbi.nlm.nih.gov/books/NBK548401/

[xii] https://pubmed.ncbi.nlm.nih.gov/35070535/

[xiii] https://www.healthline.com/nutrition/benefits-of-bcaa#The-bottom-line

[xiv] https://supplementsinreview.com/thyroid/l-tyrosine-thyroid/

[xv] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454963/