Why Do We Rely On Lean Muscle For Good Health?

December 5, 2017
/ Muscle, Nutrition, Protein, Sarcopenia

Mary and Sylvia might not differ in body weight and appearance, but could be hiding a distinct difference—one may have greater fat mass and the other more lean muscle. Why is this important?

Lean muscle’s little-known secrets

It is well-known that muscles give us strength and mobility, that we need them to walk, run, dance, kick a ball, and hold our bodies upright. Some might know that lean muscle burns more calories, helping to keep excess fat at bay, and helps maintain healthy bone density.

But the humble muscle has secret talents that are not widely flaunted.

Bodily organs like the skin, brain, heart and liver need protein to carry out their unfailing, life-giving duties. Protein continually breaks down in all tissues, which rely on a constant supply.

After a meal, blood vessels absorb and deliver amino acids—protein building blocks—to the organs. Between meals, i.e. when fasting, body tissues rely on lean muscle, their primary amino acid storage facility, to make protein.

Critically, the liver needs lean muscle protein for neogenesis—producing glucose from protein to supply energy when the liver’s stores are depleted during the fasting state.

This operation works well, so long as lean muscle stores are regularly replenished with protein stocks. However, when its protein stores fall below demand, depleted muscle mass has been associated with death from critical illness or starvation.

The body’s demand for muscle protein skyrockets when stressed by infection, burns, cancer or injury, and the stores are raided by the liver, immune system and infected wounds. Even heart disease—the Western world’s leading cause of death—is associated with declining muscle mass, strength and metabolic function.

Age brings loss of muscle mass and strength

Muscle bulk naturally declines with age and can cause sarcopenia—age-related loss of muscle mass, strength and function that may result in a vicious cycle of falls, illness, and hospitalisation.

If muscle mass is already low before illness, trauma and forced bed rest, the resulting loss may dramatically exceed an older adult’s recovery threshold. This explains, for instance, why many women over 65 who fall and break their hip never walk again.

Preventing and treating age-related loss of muscle mass

There are two simple ways to prevent and reverse accelerated loss of muscle mass and its valuable protein stores.

As previously reported, dietary protein is critical. A day’s supply is best spread over each meal. Whey powder derived from dairy is most easily absorbed—this can be used as a supplement when protein demands are high, and is best taken between meals to maintain a healthy appetite.

Other good protein sources include pea protein, eggs, dairy products, fish, chicken, meat, nuts and seeds.

Physical activity is also important. Any exercise is beneficial, but resistance strength training is most effective for building and retaining muscle mass, which can reduce weakness, frailty and the resulting accelerated decline.

Even two or three days a week of dedicated strength training at an appropriate level, combined with adequate protein intake, can build muscle strength and mass, improve bone density, and improve independence and quality of life with aging.