The Impact of Dietary Protein or Amino Acid Supplementation on Muscle Mass and Strength in Elderly People: Individual Participant Data and Meta-Analysis of RCT's.

OBJECTIVES: Increasing protein or amino acid intake has been promoted as a promising strategy to increase muscle mass and strength in elderly people, however, long-term intervention studies show inconsistent findings. Therefore, we aim to determine the impact of protein or amino acid supplementation compared to placebo on muscle mass and strength in older adults by combining the results from published trials in a meta-analysis and pooled individual participant data analysis. DESIGN: We searched Medline and Cochrane databases and performed a meta-analysis on eight available trials on the effect of protein or amino acid supplementation on muscle mass and strength in older adults. Furthermore, we pooled individual data of six of these randomized double-blind placebo-controlled trials. The main outcomes were change in lean body mass and change in muscle strength for both the meta-analysis and the pooled analysis. RESULTS: The meta-analysis of eight studies (n=557) showed no significant positive effects of protein or amino acid supplementation on lean body mass (mean difference: 0.014 kg: 95% CI -0.152; 0.18), leg press strength (mean difference: 2.26 kg: 95% CI -0.56; 5.08), leg extension strength (mean difference: 0.75 kg: 95% CI: -1.96, 3.47) or handgrip strength (mean difference: -0.002 kg: 95% CI -0.182; 0.179). Likewise, the pooled analysis showed no significant difference between protein and placebo treatment on lean body mass (n=412: p=0.78), leg press strength (n=121: p=0.50), leg extension strength (n=121: p=0.16) and handgrip strength (n=318: p=0.37). CONCLUSIONS: There is currently no evidence to suggest that protein or amino acid supplementation without concomitant nutritional or exercise interventions increases muscle mass or strength in predominantly healthy elderly people.

Vitamin B12, folate, homocysteine, and bone health in adults and elderly people: a systematic review with meta-analyses.

Elevated homocysteine levels and low vitamin B12 and folate levels have been associated with deteriorated bone health. This systematic literature review with dose-response meta-analyses summarizes the available scientific evidence on associations of vitamin B12, folate, and homocysteine status with fractures and bone mineral density (BMD). Twenty-seven eligible cross-sectional (n = 14) and prospective (n = 13) observational studies and one RCT were identified. Meta-analysis on four prospective studies including 7475 people showed a modest decrease in fracture risk of 4% per 50 pmol/L increase in vitamin B12 levels, which was borderline significant (RR = 0.96, 95% CI = 0.92 to 1.00). Meta-analysis of eight studies including 11511 people showed an increased fracture risk of 4% per µ mol/L increase in homocysteine concentration (RR = 1.04, 95% CI = 1.02 to 1.07). We could not draw a conclusion regarding folate levels and fracture risk, as too few studies investigated this association. Meta-analyses regarding vitamin B12, folate and homocysteine levels, and BMD were possible in female populations only and showed no associations. Results from studies regarding BMD that could not be included in the meta-analyses were not univocal.

Plasma very long-chain n-3 polyunsaturated fatty acids and age-related hearing loss in older adults.

OBJECTIVES: Age-related hearing loss is a common social and health problem in the older adult population. Up until now, very little scientific attention has been given to the potential role of fatty acids in age-related hearing loss. In this study we investigated whether plasma very long-chain n-3 polyunsaturated fatty acids (PUFAs) are associated with age-related hearing loss over three years. DESIGN: Cross-sectional and 3-year longitudinal analyses. SETTING: Wageningen, the Netherlands. PARTICIPANTS: 720 men and postmenopausal women (50-70 years of age) without middle ear dysfunction or unilateral hearing loss. MEASUREMENTS: Fatty acid proportions were measured in plasma cholesteryl esters. Hearing thresholds (in decibels, dB) at baseline and after three years were measured with pure-tone audiometry. Hearing loss was calculated as the increase in mean hearing thresholds in the low (0.5-kHz, 1-kHz, and 2-kHz) and high (4-kHz, 6-kHz, and 8-kHz) frequencies over three years. RESULTS: Subjects in the highest quartile of plasma very long-chain n-3 PUFA had less hearing loss in the low frequencies over three years than subjects in the lowest quartile (p < 0.01, ANCOVA, difference in mean adjusted hearing thresholds= -1.2 dB). There were no significant differences between the quartiles of plasma very long-chain n-3 PUFA in hearing loss in the high frequencies (p=0.49, ANCOVA). These associations are adjusted for baseline mean hearing thresholds, age, sex, level of education and alcohol consumption. CONCLUSION: This study is the first to show an inverse association between plasma very long-chain n-3 PUFAs and age-related hearing loss. These results are encouraging, but require confirmation from future studies.

Effect of fish oil on cognitive performance in older subjects: a randomized, controlled trial.

BACKGROUND: High intake of n-3 polyunsaturated fatty acids may protect against age-related cognitive decline. However, results from epidemiologic studies are inconclusive, and results from randomized trials in elderly subjects without dementia are lacking. OBJECTIVE: To investigate the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on cognitive performance. METHODS: Double-blind, placebo-controlled trial involving 302 cognitively healthy (Mini-Mental State Examination score > 21) individuals aged 65 years or older. Participants were randomly assigned to 1,800 mg/d EPA-DHA, 400 mg/d EPA-DHA, or placebo capsules for 26 weeks. Cognitive performance was assessed using an extensive neuropsychological test battery that included the cognitive domains of attention, sensorimotor speed, memory, and executive function. RESULTS: The mean age of the participants was 70 years, and 55% were male. Plasma concentrations of EPA-DHA increased by 238% in the high-dose and 51% in the low-dose fish oil group compared with placebo, reflecting excellent compliance. Baseline scores on the cognitive tests were comparable in the three groups. Overall, there were no significant differential changes in any of the cognitive domains for either low-dose or high-dose fish oil supplementation compared with placebo. CONCLUSIONS: In this randomized, double-blind, placebo-controlled trial, we observed no overall effect of 26 weeks of eicosapentaenoic acid and docosahexaenoic acid supplementation on cognitive performance.