Temporal Relationship between Urinary HMB Levels and Muscle Health in Community-Dwelling Older Adults at Risk of Malnutrition ^†

Abstract

Beta-hydroxy-beta-methylbutyrate (HMB) is the natural metabolite of leucine. There are very few studies which report on the temporal relationship between HMB levels following supplementation and muscle health. The objectives of this study were: (1) to investigate the effect of oral nutritional supplement (ONS) containing HMB on urinary HMB levels and (2) to determine the association between changes in HMB levels and muscle health. Urinary HMB levels indicate long-term HMB intake because levels increase and reach steady state over time. Data for analysis were derived from the SHIELD study, which was a randomised, double-blind, placebo-controlled trial consisting of 811 community-dwelling older adults at risk of malnutrition in Singapore. Participants were randomly allocated to either ONS containing HMB (0.74 g calcium HMB per serving) or placebo. Both groups received dietary counselling and consumed study products twice a day for 180 days. Data were collected at baseline, as well as days 30, 90, and 180. ONS containing HMB significantly increased urinary HMB levels in the intervention group over 180 days compared to placebo (p < 0.0001). The changes in HMB levels in the intervention group were positively correlated with changes in the total balance test score at day 90, ASMI, the SPPB score, and the score for the five chair stands at day 180, and negatively correlated with time taken for five chair stands at day 180 (all p ≤ 0.0425). There were also tendencies of positive association between HMB levels and calf circumference at day 90 and fat free mass at day 180 (both p ≤ 0.0591). However, no such associations were seen in the placebo group for the same measures above (all p ≥ 0.2537). In conclusion, consuming ONS containing HMB in community-dwelling older adults at risk of malnutrition significantly increased urinary HMB levels and correlated with improved muscle health. Therefore, ONS containing HMB should be incorporated in interventions for older adults with poor muscle health.