Every cell, tissue and organ in your body contains protein. And your body is constantly breaking down these proteins and replacing them with new ones. Given the abundant need of protein for your health, you may be searching for the best way to digest protein to maximize your levels.
You can support your body's efforts in breaking down protein by being sure to fully chew your food, which makes it easier for denaturation of the protein when it hits your stomach.
Your Protein Needs
You may have heard proteins referred to as the building blocks of life. As noted above, that may not come as too much of a surprise, since protein is needed to make and maintain every cell, tissue and organ in your body.
Protein is also needed for growth and development, specifically for children and teens, as well as during pregnancy. You also need protein to make antibodies to keep your immune system strong, and to create the enzymes that kick-start various chemical reactions — including digestion — in your body. And if you're working out to build muscle, you need to make sure you're getting enough protein to make the desired gains.
How much protein you need a day depends on many factors and there are a couple of ways you can determine your daily protein needs. According to the Food and Nutrition Board of the Institute of Medicine, the Recommended Dietary Allowance (RDA) for protein is 0.36 gram per pound of body weight. The RDA specifically means the amount of protein sufficient to meet nutrient needs of most healthy people.
If you work out or you're an athlete, your protein needs may be higher than the RDA. According to the Academy of Nutrition and Dietetics, athletes need 0.54 gram to 0.9 gram of protein per pound. So depending on your activity, if you weigh 150 pounds you may need anywhere from 54 grams (RDA) to 135 grams (max recommendations for working out) of protein a day.
MedlinePlus also suggests that your daily protein needs may depend on your overall calorie intake and should provide 10 to 35 percent of your calories, with the rest of your calories coming from a mix of carbohydrates and fats. Based on this recommendation, if you consume 2,000 calories a day than you would need roughly 50 grams to 175 grams of protein a day.
Read more: How Much Protein is Right for You?
Sources of Protein
As one of the main building blocks of life, protein is also found in a variety of food sources, including both plants and animals. However, not all food sources offer the same quality of protein.
Some foods are considered complete proteins because they contain all of the essential amino acids, which are the amino acids your body can't make and must get from the foods you eat. Other protein sources are considered incomplete proteins because they lack one or more of the essential amino acids.
Complete sources of protein include:
- Red meat
Incomplete sources of protein include:
- Beans and peas
- Nuts and seeds
While certain sources of protein may be considered incomplete, it doesn't make them any less valuable to your diet. In fact, you can easily complete these proteins by combining them, such as beans and rice or toast with peanut butter. Despite earlier beliefs to the contrary, you don't even need to eat incomplete proteins at the same meal in order for your body to get all the essential amino acids.
Protein Digestion Steps
Now that you know how much protein you need and where protein comes from, you probably want to know the protein digestion steps that occur in your body after you eat your protein food. You help digest protein at the start when you chew your food and break it up into smaller pieces. This not only makes the food easier to swallow, but improves digestion of the protein in stomach.
In your stomach, the hydrochloric acid unravels the protein in your food, which makes it easier for the enzyme pepsin to break the proteins into peptides, which are smaller strings of amino acids. Your stomach is a strong muscle and also churns and crushes the food so it can easily pass into your small intestines.
Digestion of protein in the stomach takes longer than carbohydrates and fat, which is why you may feel full longer after eating a high-protein meal.
Enzymes made in your pancreas, chymotrypsin and trypsin, are secreted into your small intestines to help digest protein by breaking them into smaller peptides and individual amino acids. Absorption of protein occurs in the lower portion of your small intestine, where the intestinal cells transport the dipeptides and amino acids to your blood, which carries them to the cells, organs and tissues that need them.
Read more: Five Stages of Protein Digestion
Improving Protein Breakdown
While you don't have much control over the breakdown of protein in your digestive system, there are steps you can take to help protein digestion. First, be sure to thoroughly chew your food before you swallow. This improves the surface area for denaturation and enzymatic action in your stomach.
You may also improve protein in your body by including protein-rich foods regularly spaced throughout the day. This may not play too much of a role in protein digestion, but it may help maintain blood amino acid levels to support protein synthesis.
Read more: What Helps Absorb Protein
Cooking to Help Digest Protein
According to an October 2017 review published in Critical Reviews in Food Science and Nutrition, proteins are not all equally digested. And if your body can't fully break down and absorb the proteins, then these undigested proteins make their way down to your colon where they undergo fermentation and produce metabolites that may increase inflammation.
While protein digestion may not be as cut and dried as it seems, the authors of this review offered suggestions on how you can improve absorption of protein from the food you eat. For example, cooking your proteins at a low temperature for a short period of time denatures the protein just enough to improve digestion. However, if you cook your foods for too long at too high a temperature, then you may denature the protein to the point that it can't be absorbed.
The authors of the review in Critical Reviews in Food Science and Nutrition also note that fermentation (how yogurt is made) improves protein digestion, as well soaking your uncooked beans before you cook them. Pressure cooking was also noted as a method of cooking to help digest protein.
Your Digestive Health Matters Too
The health of your digestive system may also affect your body's ability to break down protein, according to the review in Critical Reviews in Food Science and Nutrition. For example, if you're taking antacid medication to control your heartburn, then the acid in your stomach may not be strong enough to fully denature the protein, which may impair absorption. Gastric bypass surgery may also affect digestion of protein in stomach.
Chronic health conditions that affect the gastrointestinal system may also affect absorption of protein, such as celiac disease, Crohn's disease, chronic pancreatitis and cystic fibrosis.
If you have concerns about protein digestion and absorption related to your health or a chronic disease, consult with your doctor for guidance.
- Food and Nutrition Board of the Institute of Medicine: "Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Total Water and Macronutrients"
- National Institutes of Health: "Nutrient Recommendations: Dietary Reference Intakes (DRI)"
- Academy of Nutrition and Dietetics: "Protein and the Athlete - How Much Do You Need?"
- MedlinePlus: "Protein in Diet"
- FDA: "Protein"
- Vegetarian Resource Group: "Protein in the Vegan Diet"
- Critical Reviews in Food Science and Nutrition: "Personalizing Protein Nourishment"
- University of Hawaii: "Human Nutrition: Chapter 6. Protein: Protein Digestion and Absorption"