Effects of Dietary Protein on Muscle Mass and Frailty

Many older adults do not consume enough protein in their diet.^1-3

Insufficient protein intake can cause loss of muscle and bone mass,⁴ which can lead to weakness and frailty.^1,5-9

Diminished muscle can result in decline of physical function and independence, along with increased risk of falls. It is also associated with early mortality.¹⁰

Increasing protein intake has been clinically shown to increase muscle strength, muscle mass, and physical performance in frail elderly people.^3,11-13

Why We Need Protein

Many people associate protein powders and bars with athletes trying to build muscle. They may not realize that older adults also need abundant protein to maintain optimal health.^1,5,6,14

Proteins are made of long chains of chemical units called amino acids. Cells can produce some of these protein building blocks, but others—termed essential amino acids—cannot be synthesized in the human body and must be acquired in the diet.¹⁵

Proteins serve many purposes. About 50%-70% of all proteins in the body are found in muscles.^4,16

Studies show that after the age of 30, muscle is lost at a rate of about 3% to 5% per decade, and that accelerates with advancing age.¹⁷

Dangers of Low Protein Intake

Many older adults are at risk of suboptimal protein nutrition.^3,18,19

The most profound impact of inadequate protein is on muscle and bone. With time, too little protein may eventually contribute to:

• Sarcopenia, loss of muscle mass and strength,^17,20 and
• Osteopenia, loss of bone density and strength.^4,7

Although loss of muscle mass may be the first thing that comes to mind regarding poor protein intake, bones are also profoundly affected.⁴

Bones require calcium and other nutrients for optimal mineralization, and the scaffolding of bone tissue requires protein as well. Maintenance of healthy bone structure requires adequate protein intake, and it suffers when protein availability is insufficient.

Both sarcopenia and osteopenia can occur without any symptoms in their early stages. But as they progress, they are a major contributor to declining health in older adults.

Loss of muscle and bone are closely associated with frailty and functional disability.^4,7 Both these conditions are associated with an increased risk of falls, fractures, and other injuries, and increased risk of death.

How Much Do You Need?

Although the official Recommended Dietary Allowance (RDA) for protein intake is only 0.8 grams/kilogram per day, modern scientific, nutritional, and medical researchers generally agree that for elderly individuals and people with many medical conditions, a correct nutritional target is in the range of 1.0 to 1.5 grams/kilograms per day.^3,13,21,22

A 180-pound older individual concerned about maintaining or building muscle and bone mass should aim for approximately 80 – 120 grams of protein per day from diet and protein supplements. Since two scrambled eggs provide only 12 grams of protein, and a serving of nonfat Greek yogurt delivers just 16 grams, it is apparent that protein supplementation may be crucial for some.

For instance, whey protein concentrate powders can deliver 20 grams of high-quality protein per scoop. This can make a big difference for those having trouble meeting their daily protein quotient.

What You Need to Know

Increase Protein to Fight Frailty

• Older adults require a good intake of protein to support healthy muscles, prevent frailty and functional decline, and support healthy aging.
• Studies show that low protein intake is associated with frailty, risk for falls and other injuries, bone fractures, and other negative health outcomes in the elderly.
• Increasing protein intake can help maintain muscle mass and bone density. That can prevent frailty, loss of function, and other age-related health problems.

Human Studies of Protein Intake

Observational and clinical studies confirm the impact that adequate protein intake has on overall health.

These studies have demonstrated benefits of consuming good amounts of protein – and many of these studies used protein supplementation to augment dietary intake.^{4-7,14,18,20,23-34}

The Framingham Offspring study followed thousands of participants for an extended period of time. Over nine years of observation, individuals who consumed more protein were found to maintain a greater muscle mass. Moreover, in physically active subjects, higher protein intake was linked to an impressive 35% reduction in risk of functional decline.²⁰

In a clinical trial, poorly nourished elderly individuals who were frail or prefrail were assigned to protein-supplement interventions that augmented diet to provide 1.2 or 1.5 grams/kg protein per day. Placebo recipients consumed 0.8 grams/kg/day, the usual RDA. After 12 weeks those in the 1.5 gram/kg group, compared to the 0.8 gram/kg group, had greater muscle mass in their arms, legs, and body overall, as well as improved walking speed.¹³

Multiple reviews and analyses of the scientific literature have concluded that protein consumption higher than the RDA, in the range of approximately 1.0 – 1.5 grams/kg of body weight, including through the use of whey protein supplementation, results in better muscle and physical function outcomes. Notably, several of these scientific papers concluded that better vitamin D status leads to better results with dietary protein optimization.^3,11,12

Boost Your Protein Intake

Protein bars provide a convenient way to increase daily protein intake.

The problem is that many supposedly "healthy" bars are just candy with a protein serving added.

Some popular bars have as much as 12 grams of sugar per serving!

When choosing a protein bar, look for one with:

• No added sugar and only 1-3 grams of total sugar,
• A healthy serving of fiber, around 8 grams and,
• At least 12 to 16 grams of protein.

Many people use whey protein or plant protein powder to increase their daily protein intake.

Look for a protein powder with no artificial sweeteners (stevia is ok) which provides between 18-20 grams of protein per scoop. These powders can be mixed into numerous recipes or used as basis for a healthy smoothie.

Summary

Many older adults consume inadequate amounts of protein in their diet.

Low protein intake is associated with loss of muscle mass and strength in the elderly, along with increased risk for weak bones, falls, and fractures.

Several age-related health issues are also more common with insufficient protein intake, including age-related muscle loss (sarcopenia) and frailty.

Increasing intake of protein in the diet as well as through supplementation has been shown to help support muscle mass and physical functioning. Some studies also suggest that proper vitamin D status is essential to reap the benefits of protein nutrition.

This can help ward off functional decline, frailty, and premature death.

If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.

References

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