By Michael Ormsbee, PhD, Florida State University

Edited by Kate Findley, The Great Courses Daily

As we age, building muscle becomes more challenging. With the right protein formula, however, it is definitely still possible. Professor Ormsbee explains.

Muscle Protein Synthesis and Exercise

Along with diet and exercise, eating protein is vital if you want to achieve your ideal body composition. Typically exercise induces wear and tear on your muscles, but eating protein after exercise can prevent muscle loss and even build new muscle. Research has found that the ideal dose of protein after exercise to stimulate muscle protein synthesis, or muscle growth, as well as a host of other benefits, is about 20–25 grams (g) of protein. 

The research was done only with young men; however, most experts use this same range for young women. You may be wondering how these findings apply to older people. One study gave elderly men one, 10, 20, or 40 g of protein immediately after resistance training.

The study found that with 20 g of protein, muscle protein synthesis remained elevated compared to baseline levels of muscle protein synthesis. However, muscle protein synthesis was even higher with a 40-g dose. These findings suggest that older muscles respond better to higher protein amounts.

Recently, it has also been shown that protein amounts above the recommended dietary allowance (RDA), even in young people, may further contribute to the muscle protein balance equation by reducing muscle protein breakdown. Therefore, if you’re 20 years old and you eat or drink about 25 g of protein following a workout, you will likely maximize your ability to make new muscle proteins.

However, you need almost twice this amount—about 40 g—postexercise when you are older in order to have the same results as seen in younger people. The age at which this occurs is variable, but Professor Ormsbee recommends increasing your after-exercise protein intake after around age 40. 

Anabolic Resistance and Aging

New research has pointed out a number of reasons why this anabolic resistance, or reduced ability to grow muscle in response to consuming protein, might occur as we age. Some of these include decreased digestion and absorption of protein, decreased ability for your muscles to absorb amino acids, and decreased anabolic signaling (messages that communicate to our muscles that they need to grow) once the protein is eaten. 

The entire process for muscle repair, maintenance, and growth is blunted as we age. However, anabolic resistance in older, healthy adults can be overcome with a higher intake of dietary protein. 

One study gave healthy, older men 10, 20, or 35 g of whey protein and found that absorption and muscle protein synthesis was greater with 35 g compared to 10 g and 20 g. When it comes to protein intake, it seems that we have an anabolic threshold that rises as we get older. 

That threshold needs to be met in order to stimulate a response. An increased protein intake seems to have a long-term effect as well.

Another study looked at the level of protein intake in older men and women over three years. After a complete dietary analysis, the participants were grouped into five groups based on their levels of protein intake. 

The group that consumed the highest average amount of protein—about 19% of their typical diet over the three-year period—had the smallest loss in muscle mass over the same time. In fact, they had 40% less muscle loss than the group with the lowest protein intake that only ate about 11% protein in their diets. 

In other words, eating more protein helped these older people to maintain their muscle mass much better than lower protein intake. If you are an older adult, Professor Ormsbee recommends including a lean source of protein in every meal.

This article was edited by Kate Findley, Writer for The Great Courses Daily.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.