Different protein sources offer varying balances of amino acids. Some provide a composition of essential amino acids that aligns more closely with our needs compared to others. Each food source has one amino acid that is present in the lowest proportion relative to our requirements. A previous article discussed this concept of limiting amino acids. Another important factor to consider when assessing a food’s ability to provide necessary amino acids is the absorption of these amino acids. Not all amino acids from a food are absorbed, and there can be significant differences between various foods.
While it’s crucial to include ample fiber in our diet for overall health, the fiber content in protein sources can affect the percentage of amino acids that are absorbed. The method of food processing also influences amino acid absorption. For example, grinding beef or cooking it to different temperatures can alter its digestibility.
The Digestible Indispensable Amino Acid Score (DIAAS) was created to compare the effectiveness of different foods in supplying the amino acids we need. “Indispensable amino acids” are those that our bodies cannot synthesize—these nine amino acids are commonly referred to as “essential amino acids.” The DIAAS of a food is calculated through a standardized experiment that measures amino acid absorption combined with the food’s amino acid profile. For further details on how DIAAS is determined, you can watch this video presented by a Ph.D. student from the University of Illinois, which outlines their experiments examining the effects of processing and cooking temperatures on DIAAS.
While DIAAS is an important factor when considering how a food contributes to healthy eating, it is not the only aspect to take into account. Unless you are consuming a pure protein extract, protein sources are typically accompanied by other nutrients and calories. Animal-based protein sources often contain a significant amount of calories from fat but also provide vital nutrients such as vitamin B12 and iron. In contrast, plant-based protein sources tend to have a lot of calories from carbohydrates (and occasionally fats) but are rich in fiber and various vitamins.
For those of us who consume a lot of animal-based protein, or a large amount of protein overall; the DIAAS of a food may be less critical. Understanding the DIAAS of a food becomes particularly important for individuals in certain situations, such as those who are restricting calories to lose weight, those who consume limited animal-derived proteins, and elderly individuals. These groups should pay closer attention to how well foods provide the necessary amino acids. A registered dietitian can assist such people in developing healthy eating habits.
There remains some debate about the optimal amount of protein we should consume and which sources are the healthiest. The next article in this series will cover the USRDA guidelines for protein intake. In the meantime – if you haven’t yet, be sure to read my article on exercise for enhancing aerobic capacity. Stay tuned for upcoming articles on measles.
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Russ