Design of a randomized trial to determine the optimum protein intake to preserve lean body mass and to optimize response to a promyogenic anabolic agent in older men with physical functional limitation

Abstract

The dietary protein allowance for older men to maintain lean body mass and muscle strength and to accrue optimal anabolic responses to promyogenic stimuli is poorly characterized. The OPTIMEN trial was designed to assess in older men with moderate physical dysfunction and insufficient habitual protein intake (< recommended dietary allowance, RDA, 0.8 g·kg−1·d−1) the efficacy of consuming diets containing 163% RDA (1.3 g·kg−1·d−1) for protein, compared to RDA, to increase lean mass, muscle performance, and physical function. A second aim was to determine whether increasing protein intake to 1.3 versus 0.8 g·kg−1·d−1 would augment anabolic responses to a promyogenic agent, testosterone. For this randomized, double-blind, placebo-controlled six-month intervention trial, 92 men, 65 years or older, with Short Physical Performance Battery scores 3–10, and habitual protein intakes < RDA, were assigned to one of four groups: 100% RDA plus placebo intramuscular injections weekly; 100% RDA plus weekly intramuscular injections of 100 mg testosterone enanthate; 163% RDA plus placebo injections; or 163% RDA plus testosterone injections. All participants received portion-controlled packaged meals and group-specific dietary supplements containing either mixtures of casein and whey or carbohydrate, with identical appearance. The primary outcome was change in lean body mass assessed using dual energy X-ray absorptiometry. Secondary outcomes included maximal voluntary strength and power in leg press and chest press exercises, 6-minute walking distance, stair climbing power, and self-reported physical function. Results of the OPTIMEN trial have important implications for dietary protein guidance and policy, and efficacy of promyogenic drugs.

Weight management and physical activity throughout the cancer care continuum

“…Subsequently, some studies have demonstrated that higher protein diets (1.2‐1.6 g protein/kg of body weight per day) provide benefits beyond weight loss and may preserve lean body mass (LBM), especially in older men and women . Resistance training also has been shown to be particularly beneficial in older adults, including breast and prostate cancer survivors, to preserve LBM and bone health, maintain a higher resting metabolic rate, preserve physical functioning, and reduce falls and injury) …”

Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men

“…The design of the trial has been published previously. 31 The Optimizing Protein Intake in Older Men (OPTIMen) Trial was a ran-domized, placebo-controlled, double-blind, parallel-group trial with a 2 × 2 factorial design (Supplement 1). Institutional review boards at Brigham and Women's Hospital and Boston Medical Center approved the study.…”

Low protein intake impacts on bone mineral density

“…Peak bone density and overall BMD status are affected by several modifiable and non-modifiable cofactors. 6 Although the genetic factors are the most important contributing factors for determining BMD, they are unmodifiable and therefore it is important for public health interventions to focus on modifiable factors, Hormonal, nutritional, and mechanical factors can positively modify BMD if they are early taking into consideration. 7 Replacement of sex hormones and insulin like growth factor in deficit affected patients, optimizing bone supporting nutrients intake in an adequately and a sustainable manners, and ensuring reasonable physical activities, are mandatory for ensuring maximizing BMD in early life.…”