This study will evaluate the adaptations in skeletal muscle that occur in response to 10 weeks of weight training with or without peanut protein supplementation in older adult men and women.

Aging is associated with declines in muscle mass, physical strength and physical function. Adequate quality protein intake in aging adults is critical to preventing functional decline. Peanuts provide a unique blend of amino acids that can provide several health benefits to aging adults. While supplementing with peanut protein (PP) powder as part of a resistance training program may increase myofibrillar protein synthesis (i.e., the gold standard molecular assessment in deciphering a muscle-building response), and improve skeletal muscle quality and body composition, no study to date has made this determination.

This is a two-phase study using both novel and conventional methods to assess how PP supplementation affects muscle tissue in older individuals who engage in resistance training. These two phases will be conducted as part of a 10-week randomized controlled trial in which men and women aged 50 years and older (n=60), will be stratified by gender and randomized to a resistance training intervention (whole body, two days per week) with PP powder (72g daily; n=15 males, n=15 females) provided during the intervention (immediate group, IG) or after the intervention (wait-list control, WLC, n=15 males, n=15 females). The aims of this study are to determine the acute (deuterium oxide tracer) and chronic (peripheral quantitative computed tomography) effects of PP during resistance training on skeletal muscle myofibrillar protein synthesis rates, changes in skeletal muscle size and quality, changes in whole and appendicular body composition (dual energy x-ray absorptiometry), changes in inflammatory markers and the fecal microbiome.

Inclusion Criteria:

• body mass index (body mass/height squared) less than 35 kg/m2
• resting blood pressure averaging less than 140/90 mmHg (with or without medication)

Exclusion Criteria:

• known peanut allergy
• actively participating in resistance training for more than 2 days/week
• any known overt cardiovascular or metabolic disease
• metal implants that will interfere with x-ray procedures
• medically necessary radiation exposure in the last six months (except dental x-ray)
• any medical condition that would contradict participating in an exercise program, giving blood or donating a skeletal muscle biopsy (i.e. blood clotting disorder or taking blood thinners)

PI and Co-Is will be blind to participant randomization. One study staff member will be responsible for administering the supplements to participants per randomization