Written By: Melissa Harris, MS, University of Houston Dietetic Intern
Edited By: Brett Singer MS, RD, CSSD, LD with IRONMAN Sports Medicine Institute
Nutrition tactics in sport are constantly changing as athletes and practitioners alike search for ways to improve athletic performance and recovery. Plants and plant extracts contain high amounts of phytochemicals, specifically polyphenolic compounds, which are known for their strong antioxidant properties.
Anthocyanins, a particular type of polyphenol, are responsible for the blue, purple, red, and orange colors of many fruits and vegetables and can be found in berries such as the New Zealand blackcurrant (Braakhuis, Somerville, & Hurst, 2020). The suggested anti-inflammatory and antioxidant properties of this plant extract have led researchers to study the use of New Zealand blackcurrant extract as a way to improve physical performance and recovery in sport.
It is suggested that the regular consumption of anthocyanins found in New Zealand blackcurrant extract may improve physical performance in sport, promote enhanced recovery, lower blood pressure, increase the oxidation of fats, and may offer some cardioprotective benefits (Naderi et al., 2018).
When anthocyanin-rich blackcurrant extract is consumed before exercise, there is an increase in the release of nitric oxide which causes blood vessels to relax and widen. This in turn lowers blood pressure and allows more oxygen-rich blood to reach the working muscles or peripheral areas of the body (Cook, Myers, Blacker, & Willems, 2015). The increases in oxygen-rich blood to the working muscle during exercise may reduce fatigue and enhance athletic performance.
A study using both trained and recreationally trained youth football players found that New Zealand blackcurrant extract reduced the fatigue index by 12% in both groups, which shows the supplements potential ability to maintain high levels of activity in lower limbs during repeated sprint tests (Godwin, Cook, & Willems, 2017). This same performance enhancing effect was seen in a study by Cook et al. (2015) where cyclists exercising in normobaric normoxic conditions saw a 2.4% improvement in their 16.1 km time-trial performance when given 300-mg of New Zealand blackcurrant extract containing 105-mg of anthocyanins for 7-days with the final dose taken 1-hour before the time-trial.
However, a separate study using a similar design as Cook et al. (2015) found no performance benefit with blackcurrant supplementation prior to a 16.1 km cycling time-trial in normobaric hypoxic conditions (Willems et al. 2019). Could this be because the cyclists were exercising in normobaric hypoxia compared to the other group of trained cyclists who were exercising in normobaric normoxic conditions? More research is needed under these conditions to determine if the supplement is effective in only normobaric normoxic conditions.
In another study using recreationally active men and women performing fasted submaximal exercise in the heat, researchers had participants consume 600 mg of blackcurrant extract daily for a 7-day period prior to completing moderate intensity exercise and found no improvements in cardiovascular function but did see a higher rate of fat oxidation in these participants (Hiles et al., 2020). Future research studies should further investigate the effectiveness of NZ blackcurrant extract in various training environments and conditions.
Although the literature is still rather inconclusive as to a specific dose recommendation, there are several studies which suggest individuals should consume between 300-600 mg of blackcurrant extract, which contains about 105-210 mg of anthocyanins, daily for at least 7-days with the last dose being consumed 1-2 hours prior to exercise (Cook et al., 2015; Cook et al., 2017; Hiles et al., 2020; Willems et al.,2017). The acute functional benefits of this supplement are highly reliant upon its bioavailability and bioactivity and show both a time and dose-dependent increase of anthocyanins within the plasma 1-hr after ingestion, with peak anthocyanin levels reaching the blood stream around 2-hours after consumption (Lomiwes et al., 2019).
More research is needed to study any adverse side effects or negative interactions while using this supplement. Current literature reports only mild side effects consisting mainly of gastrointestinal discomfort at high doses, however future studies should look for any negative interactions that may have detrimental outcomes on performance or overall health and therefore contradict the use of this supplement.
At this time, it seems that the suggested performance enhancing benefits of this supplement are best suited for athletes performing short duration, moderate to high intensity exercise, but several other key properties of blackcurrant extract may provide health benefits to individuals with chronic illness such as cardiovascular disease. As more details emerge, practitioners and athletes may gain confidence in the potential performance and health benefits related to New Zealand blackcurrant supplementation.
Have questions? Please feel free to talk to an Athlete Training + Health Performance Coach or Brett Singer, Sports Dietitian MS, RD, CSSD, LD with the IRONMAN Sports Medicine Institute. Brett can be reached at email@example.com or can be found on Twitter at @bsinger10.
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