Beetroot Juice That Boosts Your Performance (#04)

If you haven't been living under a rock this past year, you've surely noticed the beetroot hype. We can almost guarantee that the number of juicers sold to you runners, skiers, cyclists, and triathletes in 2015 is directly related to the amount of articles published about beetroot. 

Beetroot juice has evolved from a trend to one of the most talked-about performance aids in endurance sports. Here, we clear up what it actually is in the beetroot that does the trick, what the research says, and how significant the effect really seems to be. The picture is quite clear: nitrate can help the body work more efficiently and provide a small yet valuable boost in performance, especially for recreational and well-trained athletes. This makes beetroot juice a simple way to try to get a bit more out of your body before training and competition. 

The active compound we're interested in from beets is nitrate. Nitrate is present in varying amounts in most vegetables, but is highest in beets, rhubarb, and leafy greens like arugula and spinach. Over the past five years, research has explored nitrate's impact on performance, providing us with sufficient data to confidently consider beet juice, or at least nitrate, as the "natural" performance enhancer of the new era.

When you consume beet juice, you intake nitrate, which is initially converted to nitrite in the mouth, then swallowed and ultimately broken down into the bioactive molecule nitric oxide (NO). Nitric oxide signals the smooth muscles in your blood vessels to relax — resulting in blood vessels becoming less rigid and widening, which increases blood flow to working muscles. This is also where you can notice the blood pressure-lowering effect, whether you are an athlete or not. Beet juice also seems to support cardiovascular health.

For athletes, we've found that we can optimize our mitochondria by up to 20 percent. If you're not entirely familiar with mitochondria, they can be described as the cell's powerhouse where energy is produced. In a study from the Karolinska Institute, a 3-day loading phase was tested where participants consumed 0.1 mmol of nitrate per kilogram of body weight per day (a total of 7.5 mmol for a 75 kg athlete, equivalent to about 7.5 dl of beetroot juice). The results showed that the mitochondria could produce as much energy as before, but required 5% less oxygen. This means less energy wasted at a cellular level. The same research team conducted 2-3 similar studies with similar findings — so it's definitely not a one-time occurrence.

Beets naturally contain significantly more active substances than just nitrate. However, when researchers removed the nitrate from the beetroot juice, while keeping all other factors (taste, smell, consistency) the same, no performance enhancement occurred. While other substances in beets might interact with the nitrate, we can most likely conclude that nitrate is primarily responsible for the positive effects observed.

The most notable effects are observed among recreational and moderately trained cyclists. The findings reveal everything from a 10–20% increase in time to exhaustion to a 5–10% reduction in oxygen consumption at a specific workload, both in low and high-intensity performance.

Our bodies have a limited amount of blood. If more blood circulates to the legs during a race, it stands to reason that blood flow to the gut might decrease, potentially raising the risk of stomach problems (see the article in the previous issue about gut problems). Fortunately, research indicates that the increased blood flow and oxygen transport to your muscles occurs without reducing blood flow to the stomach and intestines. This shows how intelligent our bodies are: they make smart choices, optimizing blood circulation rather than just distributing it randomly among body parts.

Aside from the Karolinska study noting an oxygen-saving effect, another study found similar results among well-trained cyclists after consuming beet juice (6.2 mmol Beet It) 2.5 hours before starting. They experienced just over a 3% lower oxygen cost for over 80 km of cycling. In reality, they had "only" 1.8% lower oxygen consumption, yet they managed to produce 1.3% higher power output (238 W vs 235 W average over those 80 km). So, while muscle efficiency remained constant, the increased efficiency led to enhanced performance.

These cyclists were highly trained, averaging 63 ml/kg in VO2max. But when we consider elite athletes, we encounter a different situation. It's perhaps not surprising that an elite cyclist's body is more adapted and optimized for peak performance in the saddle. Nevertheless, most studies investigating the effects of nitrate supplements or beet juice on elite athletes reveal that even they experience improved performance. Although the performance gain is as modest as +0.9%, it doesn't reach statistical significance in the scientific realm. Thus, these results are often seen as too uncertain due to the potential influence of chance.

Many researchers involved in sports performance are also part of this field. It's common for a distinguished scientist to serve as a coach or nutrition advisor for elite athletes. These researchers often include a section in their studies sometimes titled "practical applications". In such sections, we learn that a 0.9% performance improvement among elite athletes is still immensely valuable in practice. For instance, there was less than a 0.5% difference between the winners and third-place finishers in the team competition during the UCI Road World Championship 2013. In 2015, the gap between the winning team (BMC Racing Team) and the third-place finishers (Movistar Team) was 1.1%. On an individual level, Vasil Kiryienka secured victory by a 9-second margin over Adriano Malori in second place - a difference of less than 0.3%. The stakes in terms of prize money and fame can be massive, even when research-based differences appear small.

A half-liter of beetroot juice contains around 5–8 mmol of nitrate, with the variation likely due to factors such as soil, weather, transport, harvest time, etc. In the 17 studies examining beetroot juice and performance, results show that the minimum level for a performance-enhancing effect is precisely 5 mmol of nitrate. No additional effect has been noted at doses over 9 mmol (equivalent to about 9 dl of beetroot juice). If you choose to drink beetroot juice as a shot in the form of U Nitrate or Beet It — the most well-known beetroot shots on the market — you consume 4.1–4.8 mmol nitrate per 70 ml shot of Beet It and 8 mmol nitrate from U Nitrate. These numbers vary slightly across different studies, probably because the nitrate content is influenced by the handling and harvest time of the beets. My recommendation is to down 1–2 shots 2.5 hours before the start to ensure you're nitric oxide optimized.

However, don't spit. Since the nitrate is converted into nitrite with the help of enzymes in the saliva in the oral cavity, and then swallowed again to eventually become nitric oxide, you interrupt the entire process if you spit out the saliva after intake. The studies that looked into this have noted that no effect of beetroot juice remains when test subjects were instructed to spit out all saliva for three hours after intake.

A newly published study in the winter of 2015 indicates that at least 1 g of nitrate a day is okay, but no upper limit has been set yet. 250 mg of nitrate (about 4 mmol) can be consumed through 100 g of leafy green vegetables, so you can thus munch on a few hundred grams of salad a day without worrying about negative effects. This can be sensible during a buffering period a few days before competition, but avoid large amounts of salad the last two days before activity as you don't want too much dietary fiber in the gut when you're competing.

It appears that the method you use to consume nitrates doesn't significantly impact the benefits. According to a review article from 2014, which analyzed 31 studies involving 300 participants, both a loading phase of up to 15 days and an acute intake of 0.5–1 liter of beet juice taken 2.5–3 hours before exercise can enhance performance equivalently.

You achieve the full effect, with peak levels in blood plasma, 2.5–3 hours after consumption. Nitrate then has a half-life of around 5 hours, allowing its effects to persist, albeit diminishing, over the next 24 hours.

Nitrate also works effectively to mitigate the negative impact on performance after blood donation (which, of course, is a great thing to do if you can). Taking seven Beet-It shots over 48 hours following donation decreases the oxygen cost of a given task by 4% and reduces performance loss caused by the donation.

The performance-enhancing effects observed in us endurance athletes include, among other things, reduced oxygen consumption, faster times over longer distances, and increased time to exhaustion during high-intensity intervals.

In summary, the figures show a performance increase of 1–3% among elite athletes and as much as 15% among recreational athletes during high-intensity intervals. So, the recommendation is 0.5 liters of beet juice or 12 beet shots before activity. It's a very cost-effective strategy to squeeze that little extra out of your body.

The final question, of course, is whether a big serving of oven-roasted beets works just as well? The answer to that question is… YES. However, you need to eat significantly more, as nitrate is heat-sensitive, and as much as nearly 80% can disappear when heated. We don't have exact figures, so we recommend juice or Beet It as the first choice. Then you can enjoy your beets at your leisure for the taste—without having to worry about the quantity.

• Drink 0.5–0.75 liters of beet juice 2.5–3 hours before the start, or…
• Drink 2 Beet It or 1 U Nitrate Shot 2.5–3 hours before the start