A recent study published within the journal Nutrients describes the consequences of plant-based protein interventions on physical function, body composition, and strengths within the older population, in addition to whether exercise improved the efficacy of those interventions.

Study: Effects of Plant-Based Protein Interventions, with and without an Exercise Component, on Body Composition, Strength and Physical Function in Older Adults: A Systematic Review and Meta-Evaluation of Randomized Controlled Trials. Image Credit: Antonina Vlasova / Shutterstock.com

Background

Aging is related to sarcopenia, which is the progressive lack of skeletal muscle mass, strength, and performance. The event of sarcopenia is related to many health-related issues, including functional decline, higher risk of falls, lack of independence, and better hospitalization rates.

A better protein intake and regular physical activity are common strategies adopted to stop sarcopenia. Nonetheless, the effectiveness of those strategies depends upon the kinds, doses, and timing of implementation.

Plant-based proteins are potential alternatives to traditional animal-based proteins. In comparison with animal protein sources, plant-based protein could be produced relatively easily and release significantly fewer greenhouse gases.

In contrast to animal-based foods, plant-based products are also wealthy in other dietary nutrients comparable to polyphenols, fiber, and unsaturated fats. Importantly, plant-based protein sources are less nutritionally effective than animal sources resulting from poor digestibility and incomplete amino acid profiles. Nonetheless, these limitations have been overcome with the event of plant-based “mylks” and meat analogs, which exhibit improved digestibility and complete amino acid intakes.

Aging is related to impaired protein metabolism resulting from changes within the digestion process, chronic inflammation, hormonal alterations, reduced muscle protein synthesis, anabolic resistance, and insulin resistance. Several studies have indicated that components of plant proteins, comparable to isoflavones in soy, have an inflammatory effect, which could ultimately prevent the event of sarcopenia. 

So far, most reviews have analyzed the effect of animal-based protein sources like whey on skeletal muscle development in younger and older populations. Thus, there stays a scarcity of systematic reviews related to the impact of plant proteins on sarcopenia.

In regards to the study

The present systemic review assessed the effect of plant-based protein on physical function, body composition, and strength in older adults 60 years of age and older. All relevant articles published between 1947 and January 2023 were obtained from databases including Embase, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Medline.

The review considered all randomized controlled trials (RCT) that compared the consequences of plant-based protein interventions with placebo treatment on body composition, strength, or physical function amongst adults 60 years of age and older. Non-English articles, animal studies, case-control studies, and non-RCT participants with cachexia or medical conditions that impacted metabolism were excluded from the evaluation.

Study findings

A complete of 8,068 articles were obtained from the initial search. After removing duplicates and matching studies with the eligibility criteria, thirteen studies were included within the review.

The consumption of plant proteins was related to improved lean muscle mass accrual and strength over time. No significant difference was observed between plant-based protein interventions and control interventions, wherein control interventions included animal protein, placebo (no interventions), exercise, and exercise + animal protein intervention.

This commentary implies that the final result of plant protein interventions was comparable to regulate interventions. Although plant-based protein interventions exhibit positive effects in older adults, more studies are needed to validate this finding.

The present study highlights that plant-based protein sources will profit older adults with impaired anabolic metabolism. Along with improving muscle mass, plant proteins also support fat mass loss, thereby demonstrating their positive effect on overall body composition.

Typically, a rise in fat mass has been linked with aging, because it contributes to insulin resistance, muscle mass decline, morbidity, and mortality risks. Due to this fact, a rise in plant protein intake would cut back fat mass in older adults.

Compared to regulate interventions, plant-based protein interventions prevent declining body strength and performance in older adults. The vitamins, fibers, minerals, antioxidants, and antioxidants in plant proteins impact muscle health by decreasing inflammation and mitigating the hostile effects of reactive oxygen species on muscle tissue, ultimately improving muscle strength and performance.

Notably, plant-based proteins were found to perform higher without an exercise component.

Conclusions

The present systematic review summarizes the effectiveness of plant-based protein interventions for improving physical function, body composition, and strength within the older population. Improved lean muscle mass and a more significant reduction in fat mass were related to plant-based intervention in older adults.

Because the current study only focused on soy protein sources, future studies are needed that include newer plant proteins, comparable to microalgae and peas, to evaluate their effect on the targeted older population.