Researchers tested whether combining exercise with soy protein could help older adults become stronger and less frail. They studied 77 people with an average age of 75 who either did exercise alone or exercise plus soy protein for three months. Both groups improved their strength, walking speed, and muscle mass, but the group that combined exercise with soy protein showed slightly better results in how quickly they could walk. This suggests that adding protein to an exercise routine might give older adults an extra boost in staying active and independent.

The Quick Take

  • What they studied: Whether older adults who exercise and eat soy protein get stronger and less frail compared to those who just exercise
  • Who participated: 77 older adults (mostly women) with an average age of 75 years living in their own homes in the community
  • Key finding: Both groups improved significantly, but the group combining exercise with soy protein showed better improvements in walking speed and overall physical strength over the 3-month period
  • What it means for you: If you’re an older adult looking to stay strong and independent, combining regular exercise with adequate protein (like soy) may help you move better and maintain muscle. However, this was a small study, so talk with your doctor before starting any new exercise or diet program.

The Research Details

This was a randomized controlled trial, which is one of the strongest types of research studies. Researchers randomly divided 84 older adults into two groups: one group did exercise only, and the other group did the same exercise but also added soy protein to their diet. The exercise program consisted of 10 one-hour sessions spread over three months. Before and after the program, researchers measured how fast participants could walk, how strong their grip was, how much muscle they had, and how tired they felt. They also did blood tests and checked their thinking abilities.

Randomized controlled trials are considered the gold standard in research because randomly assigning people to different groups helps ensure the results aren’t biased. By comparing the two groups side-by-side, researchers could see whether the soy protein made a real difference beyond just exercising.

This study design is important because it helps answer a practical question: does adding protein to an exercise program actually help older adults more than exercise alone? Many older adults struggle with weakness and frailty, which can lead to falls and loss of independence. Understanding the best combination of exercise and nutrition could help millions of seniors stay healthier longer.

This study has several strengths: it was a randomized controlled trial (the best type of study design), it measured multiple important outcomes (walking speed, muscle mass, strength), and it included real-world participants living in their communities. However, the study was relatively small (77 people analyzed) and lasted only three months, so longer-term results are unknown. The study also had mostly women participants, so results might not apply equally to older men.

What the Results Show

Both groups showed significant improvement in physical frailty scores after three months. The exercise-only group improved by about 0.82 points, and the exercise plus soy protein group also improved by about 0.82 points, showing that both approaches work well.

Walking speed improved in both groups, but the combined exercise and soy protein group showed a slightly larger improvement. The exercise-only group’s walking speed increased from 1.27 to 1.29 meters per second, while the exercise plus nutrition group improved from 1.18 to 1.27 meters per second. This means the combined group caught up and matched the exercise-only group’s walking speed by the end.

Both groups also gained muscle mass in their arms and legs, increased their grip strength, and reduced feelings of fatigue. These improvements suggest that the exercise program was effective for both groups in building strength and reducing the weakness that comes with aging.

The study measured trunk muscle (core muscles) and found improvements in both groups. Blood tests showed changes in various health markers, though the abstract doesn’t specify which ones improved. Interestingly, both groups maintained their cognitive function (thinking and memory abilities) throughout the study, which is important because sometimes weight loss can affect mental sharpness.

Previous research has shown that exercise helps older adults stay strong, and that protein is important for maintaining muscle. This study adds to that knowledge by testing whether combining them works better than exercise alone. The results suggest that while exercise is the main driver of improvement, adding soy protein may provide additional benefits for movement and walking ability, though the differences were modest.

The study lasted only three months, so we don’t know if benefits continue longer or if people stick with the program. The group was small (77 people) and mostly women, so results might be different for men or larger populations. The study didn’t compare against a group that did nothing, so we can’t say exactly how much better these interventions are compared to no treatment. Additionally, the study used soy protein specifically, so we don’t know if other protein sources would work the same way.

The Bottom Line

If you’re an older adult concerned about weakness or frailty, regular exercise (about 1 hour per week) combined with adequate protein intake appears to be beneficial. Moderate confidence: The evidence suggests this combination works, but more research is needed. Always consult your doctor before starting a new exercise program, especially if you have health conditions.

This research is most relevant to older adults (65+) who are experiencing weakness, difficulty walking, or loss of muscle. It may also interest family members and caregivers of older adults, as well as doctors and fitness professionals working with seniors. People with certain medical conditions should check with their doctor first before starting exercise programs.

Based on this study, you might expect to see improvements in walking speed and strength within 3 months of combining regular exercise with adequate protein. However, building significant muscle takes time, and maintaining these improvements likely requires continuing the exercise and nutrition habits long-term.

Want to Apply This Research?

  • Track weekly exercise sessions (aim for 1 hour per week) and daily protein intake (grams per day), with monthly measurements of walking speed or distance walked in a set time period
  • Set a goal to complete one 60-minute exercise session per week and add one soy-based protein source (like tofu, soy milk, or edamame) to your daily diet. Use the app to log both activities and receive reminders
  • Monthly check-ins to measure walking speed (time to walk a set distance), grip strength (if you have access to a grip strength meter), and overall energy levels. Track consistency with exercise sessions and protein intake to identify patterns

This research suggests potential benefits of combined exercise and soy protein for older adults, but individual results may vary. This information is not a substitute for professional medical advice. Before starting any new exercise program or making significant dietary changes, especially if you have existing health conditions, take medications, or have concerns about your health, please consult with your healthcare provider or a registered dietitian. The study was relatively small and short-term, so long-term effects are not yet known.