A new study suggests that consuming dietary nitrate, which is the active molecule in beetroot juice, significantly increases muscle force production during exercise. While this isn’t the first study to demonstrate the health and performance benefits of dietary nitrate, including boosting endurance, improving heart health and enhancing the ability to perform high-intensity exercise, researchers are just beginning to understand why this effect occurs, and how the body converts dietary nitrate that is ingested into the nitric oxide that can be used by the body’s cells.

To help close this gap in understanding, researchers at the University of Exeter and the US National Institutes of Health traced the distribution of ingested nitrate in the saliva, blood, muscle and urine of 10 healthy volunteers, who were then asked to perform a maximal knee extension exercise. The team wanted to discover where in the body the dietary nitrate was active to glean a clearer picture of what mechanisms are at work.

An hour after the nitrate was taken, participants were asked to perform 60 quadriceps contractions in five minutes at maximum intensity on an exercise machine. During the exercises, researchers found nitrate boosted muscle torque production by 7% during the first 18 contractions (The first ~90 seconds of the five-minute test), compared to when the participants took a placebo.

“Our research has already provided a large body of evidence on the performance-enhancing properties of dietary nitrate,” explains Andy Jones, professor of Applied Physiology at the University of Exeter. “Excitingly, this latest study provides the best evidence to date on the mechanisms behind why dietary nitrate improves human muscle performance.”

Previous studies have found an increase of nitrate in tissue and body fluid after ingesting labelled dietary nitrate. By using the tracer in the new study, researchers were able to accurately assess where nitrate is increased and active, and also shed new light on how the nitrate we consume is used to enhance exercise performance.

“This study provides the first direct evidence that muscle nitrate levels are important for exercise performance, presumably by acting as a source of nitric oxide,” explains Dr Barbora Piknova, research collaborator and staff scientist in the National Institute of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health. “These results have significant implications not only for the exercise field, but possibly for other medical areas such as those targeting neuromuscular and metabolic diseases related to nitric oxide deficiency.”

Previous Studies Highlight Benefits of Beetroot Juice

As mentioned, a wide range of studies have been conducted over the past 15 years that suggest beetroot juice offers some pretty potent benefits. For example, in one study, researchers gave a group of competitive male cyclists either 16 ounces of beetroot juice or 16 ounces of a nitrate-free placebo beetroot juice about 2.5 hours before completing a 2.5-miles (4-km) or a 10-mile (16.1-km) timed trial. Two to three days later, each athlete completed the workout again, this time with a different drink–distance combination. In all, each of the athletes completed four trials with two to three days separating the workouts. Once the times were tallied, the researchers found that beetroot juice improved trial time by about 2 to 3% in both the short-distance trial (lasting about five minutes) and longer-distance trial (lasting about 30 minutes) when compared to the nitrate-free placebo.

In another study, the same research team looked at the effects of beetroot juice on blood pressure; mitochondrial oxidative capacity, a marker of how efficiently and effectively the body converts food to fuel; and physiological responses such as how much oxygen is required to fuel walking and moderate- to high-intensity running and how long a participant could exercise before exhaustion. They found that participants who consumed beetroot juice had lower blood pressures and experienced a lower oxygen cost of exercise. In fact, walkers had a significant 12 to 14% decrease in the amount of oxygen needed. The authors point out that this could have significant implications for improving exercise capacity in people who suffer from certain cardiovascular and pulmonary diseases. The participants also had decreased overall maximal oxygen consumption (VO2max), but this was compensated for with an increased time to exhaustion.

What Does the Research Mean to Health and Exercise Professionals?

At this point, there’s no question that beets and beetroot juice—like many raw vegetables and juices—offer a fairly long list of benefits. While these studies have several limitations, including small sample size (10 or fewer participants), limited age range (participants were 19 to 27 years old) and gender bias (no females were studied), the cumulative results of these studies are promising.

Beetroot juice is the blended up, liquefied version of the beet, and beetroot powder is an even more concentrated form. Both products have become more widely available in the past decade or so. The taste of beetroot juice might take some getting used to, particularly for those who try to drink it undiluted. For a more palatable juice, try a 4:1 (beetroot juice: other juice) dilution with the juice of other sweeter vegetables and fruits. Oh, and don’t be alarmed if, after eating beets or drinking beetroot juice, your urine turns pink. It’s also worth noting that nitrate can also be found in green leafy vegetables.  

While one can’t say with certainty that loading up on beets will set your clients up for a new personal best, the potential benefits seem to outweigh any known risks. A noted exception may be those who are at risk of kidney stones or gout because the high oxalate content of beets could exacerbate these conditions. For most people, however, having another reason to consume more vegetables of any kind and in just about any form could be a boon for their overall health.