Short-Term Low Choline Intake May Not Negatively Affect Strength Gains in Older Adults

Abstract

PURPOSE: The micronutrient choline is a precursor to acetylcholine (ACh), which mediates skeletal muscle contraction and force production. We previously reported that 12 weeks of low choline consumption (~50% of Adequate Intake [AI]) impaired strength gains in older adults in response to resistance exercise training. The purpose of this study was to investigate whether low choline consumption for a shorter period of time has negative effects on muscle responses to resistant exercise (RE) in older adults. METHODS: Thirty one, 50-to-65-year-old, generally healthy men and women were randomly assigned to one of three choline intake groups (Low, 3.6 ± 0.6 mg/kg/d, n=10; Med, 6.0 ± 0.6 mg/kg/d, n=11; High, 8.8 ± 0.8 mg/kg/d, n=10) and underwent 3 weeks of diet and RE intervention (leg press and extension, 2x/week, 3 sets, 8-12 reps, 75% of maximum strength [1RM]; 4 bouts of maximal isometric force production on leg extension). 1RM and EMG tests were performed before and after intervention. RESULTS: While all three groups experienced significant increases in strength, there was no difference between choline groups in changes in 1RMs (Leg press, Low: 12.4 ± 12.0%, Med: 17.5 ± 10.7%, High: 15.8 ± 10.7%, p=0.588; Leg extension, Low: 17.9 ± 13.0%, Med: 15.3 ± 18.8%, High: 5.9 ± 12.2%, p=0.209). Similarly, no differences were observed in EMG amplitudes or average/peak isometric force outputs between groups. CONCLUSION: These data suggest that less than a month of low or high choline intake may not affect strength gains in older adults. It appears that only a prolonged period of low choline intake may have negative effects on muscle responses to RE.