EFFECTS OF BEETROOT JUICE, PROTEIN SUPPLEMENTATION, AND RESISTANCE TRAINING ON STRENGTH IN OLDER ADULTS

Reductions in muscle strength, lean body mass, and insulin sensitivity occur with aging; a novel intervention of dietary nitrates, protein supplement, and resistance training was tested to improve these age-related declines. Beetroot juice is a dietary source high in nitrates. PURPOSE: The primary purpose was to examine the effects of this intervention on quadriceps muscle strength in healthy older adults. Secondary outcomes were to determine feasibility regarding recruitment and intervention delivery. METHODOLOGY: Healthy older adults (n=24) were randomized into either a nitrate rich beetroot juice supplement (BRJ+) or a nitrate depleted beetroot juice supplement (BRJ-), while undergoing a 10 week progressive resistance exercise training program and consuming a protein supplement. Beetroot juice (with and without nitrate) and protein supplements were consumed immediately post-workout. STATISTICAL ANALYSIS: ANCOVA tested for intervention effects on quadriceps strength. Paired t-tests examined changes over time in variables. RESULTS: There were no significant differences between groups in quadriceps strength measures. In a pooled sample, differences (p=0.004) were shown in quadriceps strength between baseline and follow-up. The intervention was well tolerated with high session attendance and supplement consumption. Change in plasma nitrate occurred with BRJ+ but not BRJ-. Effect sizes were small (0.25 and 0.20 for BRJ+ and BRJ-, respectively). CONCLUSIONS: Dietary nitrate does not further increase strength gains in healthy older adults more than that observed with a resistance exercise and protein supplement training program. The intervention was well tolerated and may need to be applied to an insulin resistant population to reap its potential benefits.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2015

Author dc:creator

• Tweedie, Samuel Jesse

• Beetroot Juice

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10339/57158

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/57158