Ageing muscles: can an apple a day really keep the doctor away?

It doesn’t take a scientist to tell you that as we get older, our bodies tend to become smaller, weaker and frailer.

This process takes place largely because our muscles get smaller as we age. In the 1990s, the phenomenon was given the term ‘sarcopenia’ – literally, ‘flesh poverty’. Although a natural condition, it can be detrimental to our quality of life and independence, especially as we enter the later stages of life.

So, what does sarcopenia mean for our general health?

Well, for starters, this loss of muscle is a major cause of falls in the elderly and increases the risk of bone fractures. Reduced muscle mass may also increase the risk of other diseases such as type 2 diabetes and heart failure.

Perhaps the biggest problem, though, is the impact it can have on our level of independence, which can be severe.

However, more hopeful news may be on the way.

Our muscles are made up of proteins, and muscle size depends on two key factors: our bodies’ ability to build new proteins and their capacity to break them down.

Think of a wall of bricks. At one end, someone is laying new bricks and building the wall. At the other end, someone else is removing bricks and taking the wall down. The wall is your muscle, and the bricks are proteins. This is how our muscle is maintained: through a dynamic balance of building new proteins and breaking down old ones.

As we get older, we become much less capable of building the wall and better at breaking it down. This is when we start losing muscle.

When you sit down for dinner tonight, the protein in your meal is broken down and absorbed through the gut, eventually finding its way into the bloodstream. Our muscles can sense this and respond by building new proteins. Over a long period of time, our muscles begin to grow.

However, during ageing our bodies become resistant to the effects of protein. In fact, we may need nearly double the amount of protein from our meals compared with when we were younger to maintain our muscle size.

Researchers at the School of Sport, Exercise and Rehabilitation Sciences at the University of Birmingham are trying to identify small nutrients from common foods that could help fix the problem of age-related muscle loss. There is one nutrient in particular that might help.

The nutrient is called ‘ursolic acid’ and is found primarily in the skin of apples. It can also be found in some herbal extracts, such as rosemary plant leaf. Recent research in mice has shown that it has the ability to prevent muscle loss during periods of wasting (such as during the wearing of a plaster cast following bone fracture). Researchers are attempting to find out whether the same thing happens in humans.

So, can an apple a day really keep the doctor away?

It’s too early to tell at the moment. For now, it’s important to remember that the food we eat and our daily activity levels both play key roles in the health of our muscles and our general wellbeing.

As for the apple; time will tell.

Dan Craig
Doctoral Researcher in Nutrition and Metabolism, University of Birmingham