Betalain-rich concentrate improves exercise performance

Relation

Montenegro CF, Kwong DA, Minow ZA, Davis BA, Lozada CF, Casazza GA. Betalain-rich concentrate supplementation improves exercise performance and recovery in competitive triathletes.Appl Physiol Nutr Metab. 2017;42(2):166-172.

Draft

Participants were supplemented with beetroot concentrate for 6 days and then completed 2 double-blind, randomized, time-challenged crossover tests that began 7 days apart. Exercise trials consisted of 40 minutes of cycling (75 ± 5% maximal oxygen consumption) followed by a 10 km timed run. Participants returned 24 hours later to complete a timed 5K run to assess recovery.

Participant

Twenty-two (9 men and 13 women) triathletes (age 38 ± 11 years) recruited from the University of California in the Davis area; All participants trained more than 5 hours per week, had completed a triathlon within the last year and were non-smokers in good health.

Study medication and dosage

Six days before each exercise trial, participants took either a beetroot-rich concentrate (BRC) (100 mg/d) or a placebo. On day seven, participants received half their dose of BRC (50 mg) or placebo and began a series of exercise trials 2 hours later. This beet concentrate was characterized by the fact that it contained neither sugar nor nitrate.

Target parameters

Time to complete the 10K and 5K runs; serum creatine kinase; pulse rate; and perceived exertion.

Key insights

Participants ran the 10 km distance faster after taking the BRC than after taking the placebo (49.5 ± 8.9 vs. 50.8 ± 10.3 min;P=0.03). Even though they ran faster, their average heart rate and perceived exertion rating remained the same. 17 of the 22 participants ran the 5 km distance run the day after the 10 km attempt faster after BRC (23.2 ± 4.4 vs. 23.9 ± 4.7 min;P=0.003). Creatine kinase, a marker of muscle damage, increased less (40.5 ± 22.5 vs. 49.7 ± 21.5 U/L;P=0.02) compared to baseline after the 10 km run and subjective fatigue increased less (-0.05±6.1 vs. 3.23±6.1;P=0.05) from baseline to 24 hours after the 10 km run according to BRC.

Practice implications

In this study, beetroot improved 10 km running performance in male and female competitive triathletes. It also improved performance in the 5K run 24 hours after the first 10K run, and the attenuated increases in creatine kinase and fatigue suggest an increase in recovery while taking beetroot. These results support the use of beetroot for improved athletic performance.

Betalains have a wide range of biological activities with potential health benefits: they counteract inflammation, protect the liver and have anti-cancer and antioxidant effects.

Gretchen Casazza, the lead author of this study, had published a different but very similar study almost 6 months earlier that suggested similar benefits of beetroot supplementation. In the earlier study, 13 competitive runners (all male) completed the same double crossover supplementation protocol, but with a slightly different and simpler training routine. After the same 6-day routine of 100 mg BRC per day, participants spent 30 minutes on a treadmill and then completed a 5 km time trial. At the same training intensity, runners had a 3% lower heart rate, a 15% lower rate of perceived exertion (RPE), and a 14% lower blood lactate concentration after taking BRC compared to the control group (P=0.05). Also compared to the control, 10 of the 13 runners had faster times in the 5 km time trial (23.0 ± 4.2 vs. 23.6 ± 4.0 min) with lower RPE (P<0.05) after taking BRC. Lactate dehydrogenase, a marker of muscle damage, increased less from baseline to immediately and 30 minutes after the 5 km time trial following beetroot treatment, although there were no differences in subjective measures of muscle soreness and fatigue.¹

Suffice it to say, beetroot extract appears to be helpful for athletic performance. Given the previous publications (one of which was reviewed in this journal) on beet extracts and athletic performance, these current data are not surprising. What is surprising is that the previously assumed mechanism of action of nitrate-rich beets is related to the rapid conversion of nitrate into nitric acid. The beneficial effect of beets was thought to be due to the effect of an increase in nitric acid, but the beet concentrates used in these two Casazza studies were nitrate-free. We need another explanation for why beets help athletes.

Casazza suggests that the benefit comes from betalains. The earlier of their 2 studies appears to be the first to examine betalains alone, without nitrates, and how they affect exercise performance. All previous studies had examined beetroot juice, which contained nitrates. Lansley's 2011 study of cyclists used juice that contained 6.2 mmol of nitrates.²and Cermak's 2012 study used juice with 8 mmol of nitrates.³Again, we need to reconsider our previous assumptions as these 2 recent studies conducted by Casazza used nitrate-free beet concentrate.

Betalains, commonly used as food colorings, are the water-soluble pigments that give beets their bright red color. Betalains have a wide range of biological activities with potential health benefits: they counteract inflammation, protect the liver and have anti-cancer and antioxidant effects.⁴Betanin and betanidin, the most important antioxidant components of betalains, inhibit lipid peroxidation and heme degradation even in very low concentrations. Betalains are now considered a “new class” of dietary antioxidants.⁵

Studies show that pigments in betalains inhibit the growth of various types of malignant tumors, including breast, liver, colon and bladder cancer. Betalains fight cancer through effects on apoptosis – the process of programmed cell death that is built into all normal cells but is altered in cancer cells. Other potential mechanisms of action include negative effects on genes that promote cancer cell survival and genes that control blood vessel growth. The anticancer activity of betalains is enhanced by this multi-pronged attack on cancer cell growth.⁶

Given the evidence that betalains have a wide range of healthy effects in the body, it makes sense that betalains are the active ingredient in beets responsible for improved exercise performance.

In recent years, based on the nitric oxide theory, some have promoted beet juice extract as an herbal replacement for synthetic phosphodiesterase type 5 inhibitors such as sildenafil (aka Viagra). Research suggests that few, if any, herbs actually deliver the promised chemical effects and that when these products work, it is secondary to adulteration with active ingredients.⁷On the other hand, although we have yet to find publications on the subject, one could argue that because the betalains alone are powerful antioxidants that reduce reactive oxygen damage, like other plant polyphenols, they may protect against damage that leads to erectile dysfunction.⁸