High Quality Proteins
It's important to eat all three macro-nutrients: fat, carbohydrates and proteins. Today we will focus on the latter.
You can find proteins in lots of foods, both animal-based and plant-based. However, not all proteins are the same.
Proteins are made of smaller molecules called amino-acids - these are the building blocks of proteins. There are 20 amino-acids. High-quality proteins contain nine amino acids that are called essential.
The human body is amazing, in the sense that our body is able to produce its own amino acids, but not all 20 of them; the amino acids that your body cannot produce on its own are called essential amino acids.
Another name for High Quality Proteins is "Complete Proteins", because they contain all nine essential amino-acids.
Essential Amino Acids (9 total)
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
These amino acids are vital for building and repairing tissues, enzymes, hormones, and other body chemicals.
Here are some characteristics of High-Quality Proteins:
- Contain all essential amino acids in balanced amounts
- Easily digestible and absorbable
- Support muscle repair, immune function, and overall growth
Common sources of animal-based food contain High-Quality Proteins, like:
- Meat (beef, chicken, pork)
- Fish and seafood
- Eggs
- Dairy (milk, cheese, yogurt)
There are also plant-based sources, like:
- Soy products (tofu, tempeh, edamame)
- Quinoa
- Buckwheat
- Chia seeds
From the examples above, you can see that some carbohydrate sources, like grains, contain some protein.
Most plant-based protein is incomplete, however, there is a trick to make them complete to provide all essential amino acids. If we combine grains with legumes, we can obtain High Quality Proteins. For example:
- Rice + beans
- Hummus + pita bread
- Peanut butter + whole-grain bread
Protein quality matters because this will helps ensure the body gets all essential amino acids it needs as well as support muscle synthesis and maintenance, especially important in growth, recovery, and aging. High Quality Protein can aid in better satiety and metabolic health.
We can measure the quality of a protein; this involves evaluating how well the protein meets human amino acid requirements and how well it’s digested and absorbed. There are a couple of key methods used to measure protein quality indexes, but the PDCAAS (Protein Digestibility Corrected Amino Acid Score) is the most widely used method, recommended by the FAO/WHO for many years.
The PDCAAS compares the essential amino acid profile of the protein to a reference amino acid requirement, then it adjusts the score based on digestibility (how much protein the body actually absorbs).
The Score Range is 0 to 1 (or 0% to 100%) — a score of 1 means the protein provides 100% or more of the essential amino acids after digestion. For example:
- Egg protein and whey protein have a PDCAAS of 1.0 (highest quality).
Below are some PDCAAS scores for animal-based proteins:
- Milk protein (casein) 1.00
- Beef 0.92 - 0.98
- Fish ~0.90 - 0.92
- Chicken ~0.92 - 0.95
And here you can see PDCAAS scores for plant-based proteins:
- Brown rice ~0.47 – 0.55
- Peanuts ~0.52 – 0.70
- Black beans ~0.75
- Quinoa ~0.78 – 0.87
Look what happens when you combine plant-based proteins:
- Rice + Beans ~0.9
- Corn + Beans ~0.8 - 0.9
- Lentils + Quinoa ~0.9
- Hummus + Pita Bread ~0.85-0.9
Yes, the above shows how plant-based proteins, when combines, can increase the PDCAAS score and you can get High Quality Proteins.
Tips to Maximize Protein Quality:
- Try to include legumes + grains combinations at least once or twice per day.
- Incorporate soy products like soy milk or tofu regularly—they have some of the highest PDCAAS scores among plants.
- Include nuts and seeds for added protein and healthy fats.
- Vary your protein sources to cover all essential amino acids over the day.