This study will examine the effect of probiotic supplementation (Bacillus coagulans) on muscle protein synthesis in older adults in response to a plant-based diet.

The investigators hypothesize that probiotic supplementation will enhance the digestibility of plant protein, therefore increasing the proportion of ingested amino acids that appear in systemic circulation and enhancing rates of muscle protein synthesis.

There is increasing interest in the use of plant-based proteins, both from the perspectives of global sustainability and growing consumer markets; however, plant-based proteins are known to have lower digestibility and lower ability to stimulate muscle protein synthesis (an important determinant of muscle mass) compared with animal-based proteins. Emerging evidence indicates that the probiotic Bacillus coagulans GBI-30, 6086 (GanedenBC30) can enhance plant protein digestibility. As such, Bacillus coagulans treatment may augment rates of muscle protein synthesis in response to plant-based protein intake in humans, by increasing the proportion of ingested amino acids that appear in systemic circulation after a plant meal, as circulating amino acids act as both a trigger to stimulate muscle protein synthesis in humans as well as providing the building block for new muscle tissue. An increase in muscle protein synthesis rates would be particularly critical in older adults as it is well established that one of the key mechanisms driving the loss of muscle mass with age is a reduction in muscle protein synthesis rates in response to dietary protein intake. Therefore, if probiotic supplementation can improve muscle protein synthesis rates following plant protein consumption, this indicates it may represent an effective and environmentally sensitive strategy to attenuate adverse age-related loss of muscle mass and muscle function. This is critical as the maintenance of skeletal muscle health is an important factor in the preservation of independence and quality of life as we age.

Inclusion Criteria:

• Age: ≥65 y
• Sex: males and female
• Body mass index (BMI) between 20-35 kg/m2
• Non-smokers
• Generally healthy according to responses to a standard health screening questionnaire

Exclusion Criteria:

• Cancer (malignancy in the past 5 years)
• CVD
• Chronic kidney disease
• Liver failure
• Diabetes or pre-diabetes
• Conditions that will affect the ability to consume, digest and/or absorb the study supplement (i.e. gastrointestinal disease)
• Smokers
• Excess alcohol intake
• Regular resistance training
• Total walking incapacity
• Musculoskeletal or neuromuscular impairments
• Medications interfering with muscle metabolism
• Ongoing probiotic supplementation
• Antibiotic use in the previous 6 weeks
• Significant body mass loss in the 1 month period prior to the study

Research results will be published in a peer-reviewed journal once the study has finalised and the data has been analized.