When guided by science, many options are available to achieve a healthy diet. While eating both animal- and plant-based foods is important for consumers to achieve a balanced diet that is both tasty and easy to enjoy, protein quality is an important factor to consider. Optimal protein intake supports not only muscle health, but also many other physiological functions.

Protein quality

Protein can be found in a wide variety of foods; however, the quality of the protein differs based on the amino acid composition. High-quality complete proteins deliver all nine essential amino acids (EAAs) that the body can’t naturally make on its own. Among the highest-quality proteins available are whey and casein, which are derived from milk.

If you look at the concentration of EAAs on a gram-for-gram basis, dairy proteins provide one of the highest concentrations available because they are the leading source of the branched-chain EAA leucine. This is important because leucine is the primary driver of muscle protein synthesis and leads to the building and maintenance of muscle.

Other than soy, plant proteins have lower protein quality scores because they contain lower amounts of EAAs and/or are missing some EAAs entirely. As a result, one must consume more of the food or protein source or combine different sources to obtain the same level of EAAs that are found in high-quality proteins such as dairy protein. This also often means consuming larger food volumes and more calories to match the same level of EAAs.

Impacts on human health

Research demonstrates the efficacy of dairy proteins in supporting muscle health — particularly in the context of sports and exercise. Along with resistance training, consuming high-quality proteins helps mitigate the gradual loss of muscle mass and function — known as sarcopenia — that occurs with aging, starting around age 40.

Additionally, recent studies show the benefit of whey proteins in modifying the negative impacts of physical inactivity due to reduction in daily physical activity or short-term bed rest, as well as improving recovery during rehabilitation and return to normal activity. In 2020, more positive reviews were unveiled for dairy foods in the areas of inflammation and bone health.

With a rapidly aging society and a global pandemic that may be leading to reduced physical activity, considering protein quality is more important than ever. Dairy proteins stand out as a nutritionally complete source of protein with benefits backed by a solid body of published nutrition research.

For more information, visit ThinkUSAdairy.org.