Beetroot juice added nothing to 12 weeks of strength training in middle-aged adults
In short
Twenty-seven adults averaging 56 years old completed 12 weeks of supervised full-body resistance training twice a week while drinking either nitrate-rich beetroot juice (about 13 mmol nitrate) or a nitrate-depleted placebo every day. Training increased vastus lateralis mitochondrial content (citrate synthase activity) and most leg-extensor performance measures, but beetroot juice gave no additional benefit on any outcome.
For middle-aged lifters, a daily beetroot juice did nothing extra for strength or for the mitochondria inside the muscle. In a 12-week randomized study of 27 adults averaging 56 years old, every improvement came from the training itself.
How was it tested?
- Participants were 56±7 years old, averaging 85.9 kg and 36.1% body fat.
- Everyone did supervised full-body resistance training twice a week for 12 weeks.
- One group drank nitrate-rich beetroot juice daily (about 13 mmol); the other drank a matched nitrate-depleted placebo.
- Vastus lateralis biopsies, leg-extensor peak force, strength-endurance and fatigue were measured before training and about 72 hours after the final session.
What did training alone change?
Both groups increased citrate synthase activity, a marker of muscle mitochondrial content, along with several proteins linked to mitochondrial biogenesis and dynamics. Most leg-extensor performance measures improved too. Resistance training changed not only strength but the muscle's energy machinery.
Why didn't the beetroot juice help?
Nitrate in beetroot juice is known to support some aspects of endurance performance via nitric oxide. Taken daily alongside resistance training in this study, though, it beat placebo on no outcome at all. For lifters over 40, showing up for two strength sessions a week does far more for your numbers than the supplement. On an age-adjusted strength score, a consistently trained big-three total is what counts.
The sample was small (27) and limited to middle-aged and older adults. Acute effects of beetroot juice on endurance exercise were not studied here.
Frequently asked questions
Does beetroot juice boost the results of strength training?
Not in this study. Twenty-seven adults averaging 56 years old drank nitrate-rich beetroot juice daily during 12 weeks of resistance training, and it beat placebo on no strength, endurance or muscle mitochondrial outcome.
How much beetroot juice was used?
Participants drank beetroot juice providing about 13 mmol of nitrate every day for 12 weeks. The comparison group drank a nitrate-depleted placebo juice.
Does strength training increase mitochondria in middle-aged adults?
Yes. Twelve weeks of twice-weekly full-body resistance training increased vastus lateralis citrate synthase activity (mitochondrial content) and some proteins tied to mitochondrial biogenesis.
Is beetroot juice useless, then?
This study only tested it on top of resistance training. Earlier research suggests acute nitrate-rich beetroot juice can improve some aspects of endurance performance, which this study did not examine.
Source: PubMed