Researchers looked at 63 studies involving nearly 5,000 people over age 50 to see if certain foods and supplements could help prevent muscle loss that comes with aging. They found that eating more fiber-rich whole foods and taking probiotic supplements helped people get stronger and walk faster. High-protein diets helped women build more muscle, especially when followed for at least 12 weeks. These findings suggest that simple dietary changes might help older adults maintain their strength and independence as they age.

The Quick Take

  • What they studied: Whether eating certain foods or taking gut-friendly supplements could help older adults keep their muscles strong and prevent age-related muscle loss
  • Who participated: Nearly 5,000 people over age 50 from 63 different studies, with about 59% being women
  • Key finding: Probiotic supplements helped people gain about 4 pounds of muscle strength and walk slightly faster, while fiber-rich foods also boosted strength
  • What it means for you: Adding probiotics or more whole foods with fiber to your diet might help you stay stronger as you age, but talk to your doctor first

The Research Details

This was a meta-analysis, which means researchers gathered data from 63 separate studies that had already been completed. They looked at studies testing different dietary approaches including high-protein diets, fiber-rich foods, weight-loss diets, and supplements like probiotics and prebiotics. All studies focused on people over 50 years old and measured things like muscle strength, walking speed, and muscle mass.

By combining results from many studies, researchers can get a clearer picture of what really works than any single study could provide. This approach helps identify patterns that might be missed in smaller individual studies.

Most of the individual studies had some quality issues, which means the results should be interpreted carefully. The researchers used standard methods to assess study quality and only included studies that met basic scientific standards.

What the Results Show

Probiotic supplements showed the most consistent benefits, helping people gain about 1.9 kg (roughly 4 pounds) of muscle strength and walk 0.08 meters per second faster. Diets rich in fiber from whole foods also improved muscle strength by about 1.25 kg. High-protein diets helped build muscle mass, but mainly in women and when followed for at least 12 weeks. Weight-loss diets helped preserve muscle mass, but only in people under 60 and when the diet lasted less than 12 weeks.

The benefits varied depending on age, gender, and how long people followed the interventions. Women seemed to respond better to high-protein diets than men. Shorter interventions worked better for weight-loss approaches, while longer interventions were needed for protein-based approaches to show benefits.

These findings build on previous research showing that diet can influence muscle health in older adults. The probiotic findings are relatively new and suggest that gut health might play a bigger role in muscle maintenance than previously understood.

Many of the original studies had design flaws that could affect the reliability of results. Most studies didn’t measure gut bacteria changes, so researchers couldn’t confirm whether gut health improvements were responsible for the muscle benefits. The studies varied widely in their methods, making it harder to draw firm conclusions.

The Bottom Line

Consider adding probiotic supplements or probiotic-rich foods to your diet, and focus on eating more fiber from whole foods like fruits, vegetables, and whole grains. Women over 50 may particularly benefit from ensuring adequate protein intake for at least 12 weeks to see muscle-building effects.

Adults over 50 who want to maintain their strength and independence should pay attention to these findings. People already experiencing muscle weakness or those at risk for falls may find these approaches especially helpful, but should consult healthcare providers first.

Some benefits like improved strength might be noticeable within a few weeks of taking probiotics, while muscle-building effects from high-protein diets typically require at least 12 weeks of consistent intake to become apparent.

Want to Apply This Research?

  • Track daily fiber intake from whole foods and probiotic consumption, aiming for 25-35 grams of fiber daily and regular probiotic intake through supplements or fermented foods
  • Add one probiotic-rich food daily (like yogurt, kefir, or sauerkraut) and increase whole food fiber by including more fruits, vegetables, and whole grains at each meal
  • Monitor muscle strength through simple tests like chair stands or grip strength measurements monthly, while tracking dietary changes weekly to identify what works best for your body

This information is for educational purposes only and should not replace professional medical advice. Consult your healthcare provider before making significant dietary changes or starting new supplements, especially if you have existing health conditions or take medications.