Complete Protein Sources: Unlocking the Secrets

Complete protein

Complete Protein Sources

Protein plays a vital role in our overall health and well-being, acting as the building blocks for our body’s cells, tissues, and organs. As such, it is important to ensure we consume adequate amounts of high-quality protein to support our body’s functions. However, not all protein sources are created equal.

Complete protein sources, which contain all nine essential amino acids required for optimal health, are particularly important in maintaining a balanced diet. In contrast, incomplete protein sources lack one or more of these essential amino acids. In this comprehensive guide, we will delve into the world of complete protein sources, discuss their importance, and explore various animal-based and plant-based options to help you make informed decisions about your protein intake.

The Essential Amino Acids

Amino acids are the building blocks of proteins, and our body requires 20 different amino acids to function properly. Among these, nine are considered “essential,” as our body cannot synthesise them and we must obtain them through our diet. These essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Each of these amino acids plays a unique role in the body, from supporting growth and repair processes to aiding in the production of hormones and neurotransmitters. Because our body cannot store essential amino acids, it is crucial that we consume a well-rounded diet that includes a variety of complete protein sources to meet our daily requirements.

Complete Protein Sources: What Makes Them Complete?

A complete protein source is one that contains all nine essential amino acids in sufficient quantities to support the body’s needs. The amino acid profile of a protein source is the proportion of each essential amino acid it contains, and it plays a significant role in determining the quality of that protein source.

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is a widely accepted method for evaluating the quality of protein sources based on both the amino acid profile and the digestibility of the protein. A protein source with a PDCAAS of 1.0 is considered complete and of high quality, as it provides all the essential amino acids in the right proportions and is easily digestible. By incorporating complete protein sources into your diet, you ensure that your body receives the necessary nutrients for growth, maintenance, and repair.

Animal-Based Complete Protein Sources

When it comes to complete protein sources, animal-based options often come to mind. Examples of animal-based complete protein sources include meat (such as beef, pork, and lamb), poultry (like chicken and turkey), fish (salmon, tuna, and cod), eggs, and dairy products (milk, cheese, and yogurt). These foods typically have a high PDCAAS, providing all nine essential amino acids in sufficient quantities.

Animal-based proteins also tend to be more easily absorbed and utilised by the body. However, there are some drawbacks to relying solely on animal-based protein sources. These can include concerns about saturated fat and cholesterol content, as well as ethical and environmental considerations associated with animal agriculture. To maintain a balanced and sustainable diet, it is important to consider a variety of protein sources, including plant-based options.

Plant-Based Complete Protein Sources

Contrary to popular belief, there are several plant-based complete protein sources that can provide all nine essential amino acids in sufficient quantities. Some notable examples include quinoa, soy (tofu, tempeh, and edamame), and buckwheat. Incorporating these plant-based options into your diet offers numerous benefits, such as lower levels of saturated fat and cholesterol, and a higher intake of fiber, vitamins, and minerals.

Additionally, choosing plant-based protein sources can have positive environmental impacts, as they generally require fewer resources and produce fewer greenhouse gas emissions compared to animal-based protein sources. However, it is important to note that some plant-based proteins may have lower digestibility rates than animal-based proteins. To ensure optimal absorption of essential amino acids, it is recommended to consume a variety of plant-based protein sources and to include complementary proteins when needed.

Combining Incomplete Protein Sources for a Complete Profile

For those who wish to rely more on plant-based proteins or who have limited access to complete protein sources, there is a simple solution: combining incomplete protein sources to create a complete amino acid profile. This concept, known as complementary proteins, involves pairing two or more foods that, when eaten together, provide all nine essential amino acids. Classic examples of complementary protein pairings include rice and beans, hummus and pita bread, and corn and legumes.

By incorporating a variety of complementary proteins into your diet, you can ensure that you are still meeting your body’s essential amino acid requirements even if you are not consuming complete protein sources at every meal. This approach allows for greater flexibility in meal planning and can help support a diverse, well-rounded diet.


Understanding the importance of complete protein sources and incorporating them into a balanced diet is crucial for maintaining optimal health. Both animal-based and plant-based complete protein sources offer unique benefits, and diversifying your protein intake can help ensure that you receive all the essential nutrients your body requires.

Additionally, combining incomplete protein sources through complementary proteins is an effective strategy for those who wish to focus on plant-based proteins or who have limited access to complete protein sources. By exploring different sources and combinations of proteins, you can support your body’s needs while promoting a sustainable and diverse diet.

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