The effects of resistance exercise and leucine-enriched essential amino acid supplementation on muscle mass and physical function in post-gastrectomy patients: a pilot randomized controlled trial.
Atsushi Sawada, Kentaro Yoneta, Eri Togashi and 7 others
PMID 38694013WHAT IT FOUND
Muscle mass fell by 5.46% with exercise plus a leucine supplement and 6.56% without, over three weeks after stomach cancer surgery.
No difference between the groups. Leg strength improved only in the exercise group. Two quality-of-life scores rose there too.
Key findings
01Adding lower-limb resistance training and a leucine-rich amino acid supplement to standard care did not prevent muscle loss after stomach cancer surgery: there was no significant difference between the groups in body weight, muscle mass or fat mass, and muscle mass ended 5.46% below preoperative levels in the intervention group and 6.56% below in the control group.
02Leg strength improved significantly over the three weeks in the group given exercise plus the supplement and did not change significantly in the control group; by day 21 it was significantly higher than before surgery.
03Quality-of-life scores for physical functioning and mental health were significantly higher at day 21 than before surgery in the exercise plus supplement group.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only five people per group were analysed. The authors did no sample size calculation and describe the study as a pilot, so it can easily miss a real difference and cannot show whether the programme works. People knew whether they were in the exercise group, and the groups were not evenly matched at the start: the intervention group began with significantly lower body mass index and body fat, which the authors say they could not rule out as influencing the results. Four of the 14 randomised participants (29%) were not analysed. The resistance training and the leucine supplement were given together with standard care, so the study cannot say which part, if any, produced the improvements in leg strength or quality of life. It was a single-centre study and was registered retrospectively in 2023, after the patients had been enrolled between 2015 and 2017. Blood amino acid levels were not measured, so the authors could not test whether poor protein digestion and absorption after gastrectomy blunted the supplement's effect. Energy intake after day 7 was below requirements, at 70.6-82.9% of the target in the intervention group, which the authors suggest may be why muscle loss continued despite adequate protein intake.
Declared interests
The study was supported in part by Grants-in-Aid for Regional R&D Proposal-Based Program from the Northern Advancement Center for Science & Technology of Hokkaido, Japan. The authors declare they have no competing interests. The supplement used was a commercial product, Amino Care Jelly Leucine 40 (Ajinomoto Co., Tokyo, Japan).
The easy way to misread this
Do not read the improvements in leg strength and quality of life as proof that exercise plus leucine works after gastrectomy. The main result, muscle mass, was no different between the groups, only five people per group were analysed, and the group that exercised started with significantly lower body fat, which the authors say could have affected the results.
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