In this episode of Longevity by Design, our hosts, Dr. Gil Blander and Ashley Reaver, MS, RD, CSSD, are joined by Dr. Roger Fielding, Associate Director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Tune in as Dr. Roger Fielding describes how proper nutrition and being physically active build muscle and prevent age-related muscle loss.
Meet Longevity by Design’s podcast guest, Dr. Roger Fielding
Dr. Roger Fielding is Associate Director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. He also serves as Leader and Senior Scientist of the Nutrition, Exercise Physiology, and Sarcopenia (NEPS) Team.
Dr. Roger Fielding’s research interests include:
- The impact of exercise and physical activity on successful human aging.
- Skeletal muscle alterations with advancing age in disabled and non-disabled populations.
- Age-related alterations in the control of skeletal muscle protein turnover.
Components of muscle building
To begin, Dr. Fielding discusses the processes by which the body builds muscle. Then, he further explains the role of nutrition, specifically how protein and energy enable muscle protein synthesis. In addition to exercise and nutrition, muscle growth also has a hormonal component. Regulation of anabolic (muscle building) and catabolic (muscle breakdown) hormones influence muscle composition. "The main pro-anabolic hormones are testosterone and dihydrotestosterone. But, catabolic cytokines and pro-inflammatory molecules activate protein and muscle breakdown," explains Dr. Fielding.
How muscle mass changes with age
Next, Dr. Fielding discusses muscle loss as it pertains to aging. Sarcopenia, age-related muscle loss, is influenced by the decline of factors associated with muscle building.
"Pro-myogenic molecules— like estrogen, testosterone, DHA, and insulin-like growth factor-1—all start to decline with advancing age. There is also a simultaneous rise in the pro-inflammatory cytokines that can cause muscle protein breakdown," says Dr. Fielding. Nutrition and exercise play a role here as well. In addition to the biological factors, older individuals tend to be less active and have lower diet quality, contributing to muscle breakdown.
Interestingly, the rate at which people experience muscle loss is highly variable and dependent on multiple factors. For example, peak muscle mass during growth and development greatly influences muscle degradation later on. Additionally, certain medical conditions and incidents like hospitalizations, infectious diseases, and other comorbidities can contribute to the chronic or acute acceleration of muscle loss.
Why is muscle mass important to maintain as you age?
Muscle loss has many implications for older individuals and is a key aspect of longevity. Dr. Fielding explains, "As you lose muscle mass, you will reach a point where your ability to perform activities of daily living will be negatively affected. Once you reach that point, muscle loss can start to affect how you function in your environment—like walking, getting out of a chair, getting out of bed, and climbing stairs—and can become a barrier to maintaining an independent lifestyle."
Grip strength and walking speed are two of the most common ways to measure age-related muscle loss at a population level. "Grip strength is a great prognostic indicator of late-life disability, falls, fractures, and mortality. Additionally, normal walking speed is a very strong predictor of mortality, risk of falling, and other poor clinical outcomes," says Dr. Fielding.
Exercise for longevity
Following the discussion on muscle mass, Dr. Fielding explains the importance of exercise for health. He explains that even the health habits we adopt while we're young can influence how we age. "We shouldn't put ourselves in a situation where we worry about becoming more physically active once we get older. It's never too late to start, but you're always going to be better off if you start exercising early in life and make a lifelong commitment to it," says Dr. Fielding.
Exercise can include intentional workouts and other activities, such as walking, gardening, and yard work. Dr. Fielding explains that while some exercises may be better than others, the most important thing is finding a form of exercise that you actually enjoy. "The benefits of exercise are real, and they are substantial. However, if you don't continue the exercise program, the benefits go away. So, anything you can do to promote adherence—say exercising with your spouse or a friend—can be a great way to promote adherence and accountability."
The role of nutrition in muscle mass
When asked about nutrition considerations for older individuals, Dr. Fielding first clarifies that the current science poorly overgeneralizes the older population's needs. He argues that nutrition needs for people 65-75 years old are different for people 75-85 or 85+. "The fastest-growing segment of our older population are individuals over the age of 85 years, yet we seem to know virtually nothing about what they eat," he says. "They have high levels of food insecurity, they are isolated, and many live alone. They tend to have trouble preparing and eating food for one person."
Extensive research supports that calcium and vitamin D are crucial for bone and muscle health in the aging population. And adequate protein and energy intake are equally as important.
Advice on living a healthier, longer life
When asked for his top tip, Dr. Fielding says to have a positive outlook on life. "You need to be optimistic. Life is great, and you need to have an optimistic outlook on life and your future. If we have a positive outlook, we're all going to be better off."