Oral nutritional supplement fortified with beta-alanine improves physical working capacity in older adults: a randomized, placebo-controlled study

Abstract

This study examined the effects of an oral nutritional supplement fortified with two different doses of beta-alanine on body composition, muscle function and physical capacity in older adults. Using a double-blind placebo controlled design, 60 men and women (age ± SD = 70.7 ± 6.2 yrs) were randomly assigned to one of three treatment groups: 1) oral nutritional supplement (ONS; n = 20) (8 oz; 230 kcal; 12 g PRO; 31 g CHO; 6 g FAT), 2) ONS plus 800 mg beta-alanine (ONS800; n = 19), and 3) ONS plus 1200 mg beta-alanine (ONS1200; n = 21). Treatments were consumed twice per day for 12 weeks. At pre- and post-supplementation period, participants performed a discontinuous, submaximal cycle ergometry test to determine physical working capacity at fatigue threshold (PWCFT). Fat mass, total body and arm lean soft tissue mass (ALSTM) were measured with DEXA while muscle strength was assessed with handgrip dynamometry (GRIP) and 30-s sit-to-stand (STS) was used to measure lower body functionality. Muscle quality (MQ) was calculated with GRIPmax and DEXA derived ALSTM [GRIP (kg)·ALSTM (kg)(-1)]. Two-way analysis of variance was used to compare pre- to post-supplementation measures and group differences. There were 16 dropouts over the duration of the study. Final group sizes were ONS = 16 (m = 11, w = 5), ONS800 = 15 (m = 5, w = 10), and ONS1200 = 13 (m = 6, w = 7). No significant changes were observed for body composition or GRIP values pre to post. Significant increases in PW(CFT) were seen in ONS1200 (13.6%) and ONS800 (17.8%) pre- to post-supplementation (p < 0.05). These changes were significantly greater (p < 0.05) than the changes in ONS (-6.3%). ONS1200 and ONS had significant increases in STS (22.2 and 10.7%, respectively). While ONS significantly increased in STS, no differences (p > 0.05) in change scores were found between ONS and ONS800. ONS fortified with beta-alanine may improve physical working capacity, muscle quality and function in older men and women. These findings could have importance in the perception of frailty, and the maintenance of health and independent living in older adults.

Keywords: ALSTM; Arm lean soft tissue mass; Beta-alanine; DEXA; Dual-energy X-ray Absorptiometry; EMG; Electromyography; MQ; Muscle Quality; Muscle quality; ONS; Older adults; Oral Nutritional Supplement; Oral nutritional supplement; PWC(FT); Physical Working Capacity at Fatigue Threshold; Physical working capacity; TLSTM; Total body lean soft tissue mass.