BEETROOT JUICE AFTER 50: WHAT DIETARY NITRATE ACTUALLY DOES

Beetroot juice has one of the larger evidence bases of any supplement in the endurance world. That evidence supports some performance outcomes and not others, and which is which depends on the kind of effort you're asking it to help with.

What Dietary Nitrate Actually Does

The active ingredient in beetroot juice is inorganic nitrate. Once swallowed, some of that nitrate is reduced to nitrite by bacteria on the tongue, and nitrite is then converted to nitric oxide in the body. Nitric oxide widens blood vessels and has been proposed to make muscle contraction slightly more efficient, using less oxygen for the same work.

That is the proposed mechanism. It fits with the modest size of the effects reported below.

The Largest Synthesis

In 2025, Sports Medicine published an umbrella review by Poon and colleagues, a review of reviews pooling 20 systematic reviews with meta-analyses covering 180 primary studies and 2,672 participants.

Compared with placebo, nitrate supplementation produced statistically significant improvements on five outcomes:

• Time to exhaustion (standardized mean difference 0.33)
• Total distance covered (SMD 0.42)
• Muscular endurance (SMD 0.48)
• Peak power output (SMD 0.25)
• Time to reach peak power output (SMD −0.76)

Those are small-to-moderate effect sizes.

Where It Showed No Significant Improvement

In the same umbrella review, nitrate showed no significant improvement in:

• Time trials
• Graded exercise tests
• Maximal oxygen uptake (VO₂ max)
• Muscular strength

The improvements the review found were in open-ended efforts, the kind you continue until you can't, rather than fixed-distance performances against the clock or maximal strength.

Dose and Duration

The review's subgroup analyses found more pronounced time-to-exhaustion improvements under two conditions:

At least 6 mmol of nitrate per day, about 372 mg.

Supplementation lasting more than three days, compared with shorter protocols.

The authors also reported that beetroot juice and a high-nitrate diet offered greater benefits than nitrate salts.

The Blood Pressure Question

Nitrate's second selling point is cardiovascular. Here the findings depend on the population and on how blood pressure was measured.

A 2024 meta-analysis in Nutrition, Metabolism and Cardiovascular Diseases (Grönroos et al.) pooled 11 trials and 349 patients with hypertension and found beetroot juice reduced clinic systolic blood pressure by 5.31 mmHg (95% CI −7.46 to −3.16) versus placebo. It found no significant effect on clinic diastolic pressure or on 24-hour blood pressure, and the authors rated the certainty of evidence as low.

A 2024 randomized crossover trial in Food & Function (Fejes et al.) gave 15 older adults aged 56 to 71 with treated hypertension nitrate-rich or nitrate-depleted beetroot juice for four weeks. Nitrate and nitrite levels rose, but there were no differences in forearm blood flow, 24-hour ambulatory blood pressure, or home blood pressure between the two.

If you have hypertension or take blood pressure medication, that is a conversation to have with your physician rather than a reason to change anything yourself.

Limits the Review's Authors Named

The umbrella review's authors flagged a lack of studies in youth and older populations, who have distinct physiological characteristics. The evidence base above was not built on masters athletes.

They noted three other limitations:

• Sex balance. Women made up only 7–37% of the pooled samples in the reviews that reported it.
• Methodological quality. 12 of the 20 included reviews (60%) rated "critically low" on AMSTAR-2, a standard quality appraisal tool.
• Product variability. Commercial beetroot juice products showed considerable variation in measured nitrate content, within and between products, often differing from labeled values.

Direct older-adult performance data is small. A 2017 randomized, double-blind crossover trial in PLoS One (de Oliveira et al.) gave 12 older adults a single 100 g beetroot gel containing about 12 mmol nitrate. After a handgrip exercise, muscle oxygen resaturation was faster (1.43 vs 1.02 %/s), blood volume during recovery was higher, and the decline in handgrip strength 30 minutes later was smaller than with placebo. Twelve people and a single dose make it a pilot result.

The Protocol

• Match it to what was measured. The review's improvements were in open-ended, sustained efforts. It found no significant improvement in time trials, VO₂ max, or strength.
• The dose in the subgroup analysis: at least 6 mmol of nitrate per day. Look for nitrate content stated in mmol or mg on the label, and remember measured content can differ from the label.
• The duration in the subgroup analysis: more than three days, rather than a single dose.
• Test it in training first. Beetroot juice can turn urine and stool red. That's harmless but unsettling on race morning if you're not expecting it.
• Talk to your physician first if you take nitrate-based heart medication (nitroglycerin, isosorbide) or blood pressure medication.
• Keep expectations in proportion. The effects reported were small to moderate, on top of training, sleep, and nutrition.