歩行障害高齢者へのホエイタンパク＋筋トレの効果

歩行障害のある高齢者に対する抵抗運動にホエイタンパクを投与した効果をみたRCTを紹介します。

Chalé A, Cloutier GJ, Hau C, Phillips EM, Dallal GE, Fielding RA. Efficacy of Whey Protein Supplementation on Resistance Exercise-Induced Changes in Lean Mass, Muscle Strength, and Physical Function in Mobility-Limited Older Adults. J Gerontol A Biol Sci Med Sci. 2012 Oct 31. [Epub ahead of print]

リサーチクエスチョンは以下の通りです。

P：歩行障害のある高齢者に6ヶ月間、抵抗運動を行う際に
I：ホエイタンパクを1日40g投与すると、
C：同じエネルギーでホエイタンパクでないものを投与した場合と比較して
O：筋肉量、筋力、身体機能が改善する。
D：ランダム化比較試験

抄録しか読めていないので、コントロールの詳細不明です。結果ですが、両群とも筋肉量、筋力、身体機能が改善して、ホエイタンパク群のほうがやや改善傾向にありますが、いずれも統計学的有意差はありませんでした。以上より1日40gのホエイタンパクではさらなる効果はないという結論です。

統計学的有意差はありませんが、臨床的には無視できない差がありますので、これで無効というのは言いすぎかなと感じます。対照群の中身によります。また、日本で考えると、1日40gのホエイタンパクという量は現実的ではない気がします。1日20gまでというところでしょうか。

Abstract

BACKGROUND:

Whey protein supplementation may augment resistance exercise-induced increases in muscle strength and mass. Further studies are required to determine whether this effect extends to mobility-limited older adults. The objectives of the study were to compare the effects of whey protein concentrate (WPC) supplementation to an isocaloric control on changes in whole-body lean mass, mid-thigh muscle cross-sectional area, muscle strength, and stair-climbing performance in older mobility-limited adults in response to 6 months of resistance training (RT).

METHODS:

Eighty mobility-limited adults aged 70-85 years were randomized to receive WPC (40g/day) or an isocaloric control for 6 months. All participants also completed a progressive high-intensity RT intervention. Sample sizes were calculated based on the primary outcome of change in whole-body lean mass to give 80% power for a 0.05-level, two-sided test.

RESULTS:

Lean mass increased 1.3% and 0.6% in the WPC and control groups, respectively. Muscle cross-sectional area was increased 4.6% and 2.9% in the WPC and control groups, respectively, and muscle strength increased 16%-50% in WPC and control groups. Stair-climbing performance also improved in both groups. However, there were no statistically significant differences in the change in any of these variables between groups.

CONCLUSIONS:

These data suggest that WPC supplementation at this dose does not offer additional benefit to the effects of RT in mobility-limited older adults.