This informative post covers what impacts protein digestion and different ways to increase protein digestion to improve muscle growth and gut health.
3 Main Factors that Affect Protein Digestion
The amount of protein you digest depends on three main things: the source of the protein, your digestive capacity, and the total amount of protein you consume.
Further, the factors discussed in this informative post are based on a study done by health, nutrition, and food science experts at the University of California Davis. Remember that the factors discussed are based on the results of one study and that additional study is needed to fully comprehend the extent to which these variables play a part in our health.
- The Source of Protein
Where the protein comes from and how the protein is prepared/processed makes a difference in the digestibility of the protein.
For simplicity, we are going to compare the entire difference in digestibility between plant sources of protein and animal sources of protein.”
Animal Protein vs. Plant Protein
Where the protein comes from (the source) affects the digestibility of the protein primarily because of what the researchers refer to as “matrix effects.
Most food sources comprise of other macronutrient components along with protein, and these elements can impact the digestibility of the protein. The protein in plant sources is particularly impacted by these anti-nutritional factors.
Of plant proteins, different legumes, cereals, potatoes, and tomatoes contain inhibitors that block trypsin, pepsin, and other gut proteases that reduce protein digestibility. Below are specific examples of the:
- Legumes & cereals
- Nuts, seeds, & grains
- Contain tannins, which bind to proteins and digestive enzymes, inhibiting protein digestion
- Contain phytic acid, which binds to minerals which are necessary cofactors to digestive enzymes, reducing digestibility
- Legumes & alliums (onion varieties)
- Contain saponins, which act as a defense system for your plant, protecting it reducing digestibility
Also, many resources of plant protein have been surrounded by complex carbs, which prevent enzymes’ accessibility into the protein, further impairing digestibility.
In comparison, the digestibility of animal proteins is greater than that of plant proteins on average, 10-30%. This is likely because of the anti-nutrients & complex carbs in plant proteins that decrease their digestibility that animal fats don’t include.
Take away: animal proteins are easier to digest than plant proteins.
Preparation of this Protein
According to the study, how preparation techniques impact the protein is via altering the structure of this protein, influencing the anti-nutritional factors and complex carbohydrates, and consequently, digestibility.
A few different prep methods include heat treatments, fermentation, soaking, higher pressure, and regular meat processing measures. Below is a brief recap of how these various preparation methods impact digestibility.
Heat treatments (such as boiling, microwaving, and roasting)
- Overall, moderate temperatures and short heating times denatures protein and also deactivates anti-nutritional facets, increasing digestibility, while high temperatures for longer heating times results in chemical changes that make proteins insoluble, reducing digestibility.
- What to do: heat protein sources enough to cook them (ensuring they are “done”) but do not overcook or oxidize. Bear in mind that these impacts change with protein supply, as different protein sources require different cooking times and temperatures.
Fermentation (chemical breakdown by bacteria and fungi)
- Fermentation processes of nearly all protein sources reduce the allergenicity of a few proteins also improves the overall digestibility of the protein
- What to do: consider sometimes rotating your normal protein sources with proteins that have been fermented, such as miso and tempeh (fermented soybeans), kefir, yogurt, and sour milk (fermented milk), and/or fermented vegan protein powder.
- Soaking uncooked beans and grains improve digestibility by lowering anti-nutritional variables (possibly from them leaking out during the soaking process, as detailed here). The digestibility improves the longer the source is soaked.
- What to do: pre-soak your legumes and grains before cooking and consuming as long as you possibly can.
- For most proteins, therapy at high pressures for a varying amount of temperatures and times (the research mentions variations of 10 minutes at 20 degrees C to half an hour at 50 degrees C) denatures the protein, enhancing digestibility. On the other hand, the consequence of high-pressure cooking on protein digestibility depends on the protein source (likewise to heat therapy).
- What to do: Don’t knock pressure cooking for a preparation method, but do research beforehand about the specific protein source to determine whether that method of preparation is best or even appropriate for the source. As an example, red kidney beans demonstrated decreased digestibility after pressure cooking, so don’t pressure cook these legumes.
- Cook meat enough to no longer be raw, but avoid overcooking and long exposure to high heat
- Experiment cycling in fermented sources of protein
- Soak beans and grains – the longer the better
- Don’t fear high-pressure cooking, but ensure the protein source is compatible with this type of preparation beforehand. Probably limit this type of preparation to be safe
- Your Digestive Ability
The digestibility of protein also varies within individual consumer digestive capacity, the degree to which you can breakdown and utilize the protein. Digestive capacity is very impaired across several ailments and depends heavily on general gut health and functioning. One sign of inferior bowel health and function is a leaky gut (hyperpermeability), which has been related to the development of several other health conditions. Thus, the presence of the following conditions may be an indication of a poorly functioning gut:
- Acute inflammation conditions
- Arthritis & other chronic inflammatory conditions
- Autoimmune diseases (Hashimoto’s, lupus, multiple sclerosis, etc.)
- Celiac disease
- Chronic constipation
- Chronic diarrhea
- Chronic fatigue syndrome
- Colorectal cancer
- Esophageal cancer
- Gastric ulcers
- Inflammatory bowel diseases (Crohn’s, ulcerative colitis)
- IBS (irritable bowel syndrome)
- Metabolic diseases
- Parkinson’s disease
- SIBO (small intestine bacterial overgrowth)
- Respiratory infections
- Thyroid disorders
No causal relationship has been proven between those conditions and leaky gut. However, research strongly suggests these conditions happen in adjunct with leaky gut.
Take off: when it comes to avoiding issues connected with bad protein digestion, individuals with conditions associated with leaky gut or particular gastrointestinal ailments may consider taking extra care to choose easier to digest protein sources and preparation methods.
- Complete Protein Consumption
A third variable the researchers discussed associated with poor protein digestion is the overconsumption of protein.
Past research has debunked the idea that consuming more than the recommended quantities of protein is taxing to the liver, however, little research was explored that reveals the effects of too much protein on the intestine and other intestines.
The information demonstrates that even just increasing protein Intake from 15.4% to 23.8% of the diet for one week led to increased fecal markers of putrefaction, and another study has revealed improved ammonia production and putrefactive products in the colon from increased protein consumption.
What is considered too much or too high of protein not only depends on the characteristics and needs of the individual, but on somebody’s digestive capacity as discussed earlier, and the digestibility of the protein source itself?
Too much indigestible or difficult to digest fats may increase the opportunity of undigested protein living into the colon, increasing the amount of putrefaction and dangerous metabolites produced.
Ultimately, more research is needed to determine exactly what constitutes excess levels of every one of these markers, but the data does indicate that the overconsumption of protein can impair optimum gut health, especially in people who have impaired digestive capacity, to begin with.
Take away: be mindful of the recommended amount of protein for your particular attributes and targets, and avoid consuming high levels of a protein that’s typically more difficult to breakdown and digest.
If you need a higher protein consumption, consider supplementing in easier to digest fats, like hydrolyzed whey proteins, which are pre-broken down into amino acids, which makes digestion simpler and quicker.
6 Ways to Improve Protein Digestion for Muscle Growth & Gut Health
- Lower your protein intake
- Consume easily to digest proteins (link to another post)
- Increase your fiber intake
- Supplement with digestive enzymes (link to another post)
- Buy high-quality animal and plant protein sources
- Prepare protein properly to increase digestibility and avoid oxidization