Are all proteins equal? The truth about protein

What are proteins

Protein is an important nutrient that is responsible for a number of biological processes, such as muscle formation, cell and tissue repair, immune function, and regulation of hormones. Proteins are made up of smaller units called amino acids, and along with fat and carbohydrates, protein constitutes what we know as macronutrients. 

Essential amino acids (EAA)

Amino acids are molecules that are often referred to as the building blocks of protein. Each protein has its own sequence of amino acids and each sequence gives the protein a different structure and a different function in the body. Here’s an easier way to understand amino acids – think of them as letters of the alphabet. When you combine letters in different ways, you get different words. The same goes for amino acids. When they are combined in different ways, we get different proteins.

While there are over a hundred thousand proteins in our body, each with its own amino acid structure, our body requires 20 types of amino acids to function properly. Of these 20, our body cannot make 9 essential amino acids, which we must get from food sources. 

All proteins are not equal

Despite their importance in regulating crucial bodily functions, not all proteins are equal. It is important to understand these differences to make more informed dietary choices. Let us take a look at these differences and examine how one can get the most out of protein.

Complete vs incomplete proteins

Proteins are deemed complete or incomplete based on their amino acid profile. Complete proteins contain all 9 essential amino acids that our body cannot produce, whereas an incomplete protein lacks one or more of the 9 essential amino acids. 

Examples of complete proteins are:

1. Meat: Chicken, pork, mutton
2. Dairy: Milk, curd, cheese
3. Eggs
4. Fish: Salmon, tuna, cod
5. Grains: Quinoa, buckwheat
6. Soy products: Edamame, tofu, tempeh

Examples of incomplete proteins are:

1. Legumes: Lentils, chickpeas, black beans
2. Nuts: Almonds, walnuts, cashews
3. Seeds: Sunflower seeds, pumpkin seeds
4. Grains: Rice, wheat, oats
5. Vegetables: Spinach, broccoli

Bioavailability 

Bioavailability and digestibility are two metrics that are used to assess the quality of proteins. The amount of protein that your body can actually utilize is called bioavailability. There are several factors that affect protein usability in the body:

Digestibility: How well your digestive enzymes are able to break down protein.

Amino acid profile: Proteins that have all 9 essential amino acids are more bioavailable.

Absorption: How well the amino acids are absorbed into your bloodstream.

Preparation: Preparation methods like cooking and fermentation can improve digestibility by denaturing proteins and reducing the presence of anti-nutritional factors.

Source: Animal protein has better bioavailability as compared to plant protein because of its complete amino acid profile.                 

How to get all 9 EAAs as a vegetarian

Vegetarians might find it hard to find a source of complete protein. However, it is still possible to get all 9 essential amino acids as a vegetarian. Let us take a look at some methods to load up on the EAAs: 

Mix-and-match foods: While some vegetarian sources of food like quinoa and curd do contain all 9 EAAs, most other sources are incomplete proteins. However, combining various vegetarian food items with different amino acid profiles can help you obtain all essential amino acids. 

Supplement: You can always consider including a vegetarian protein supplement, in case you struggle to meet your protein needs through food alone. They contain all 9 essential amino acids, providing a good amount of bioavailable protein.

Diversified diet: You don’t necessarily have to consume foods with a variety of amino acid profiles in every single meal. Simply combining a variety of vegetarian foods across your meals will ensure that you end up getting all essential amino acids in a day.