October 17, 2025, 1:53 pm | Read time: 4 minutes
Small study with big insights: An extract from black currants may improve running performance. The reason is believed to be anthocyanins, plant pigments found in many fruits and vegetables. However, the promising results so far apply only to men. FITBOOK author Friederike Ostermeyer explains what exactly British researchers have discovered.
There are many methods to improve one’s running performance. In addition to getting enough sleep and proper nutrition, certain mental tricks or even choosing the right words can yield measurably better results (FITBOOK reported). Now, British researchers from the University of Chichester have identified black currant extract as another aid for a quick sprint. The product, available as a dietary supplement, contains about 210 milligrams of anthocyanins per dose, which are ultimately responsible for the increased power. What improvement in running performance can users expect?
“Miracle Substance” Anthocyanins–Natural Doping?
Numerous studies suggest that anthocyanins can temporarily improve muscle blood flow and oxygen supply, thereby enhancing endurance.1 The secondary plant pigment is responsible for the red, purple, or black color of blueberries, red cabbage, cherries, and black currants. The more science discovers about it, the more remarkable the substance appears. It is said to slow aging processes, protect against cancer, or stop inflammation (FITBOOK reported). Therefore, the researchers wanted to find out how high doses directly affect athletic performance. The results were published in the journal “Nutrients.”2 Important note: No dietary supplement manufacturer was financially involved in the study.
Also interesting: How to Run Faster?
How the Study Was Conducted
The researchers recruited 16 young, physically active men. They each received 600 milligrams of black currant extract (equivalent to 210 milligrams of anthocyanins) for one week and, after a two-week break, another week of a placebo. Of course, the men did not know whether they were receiving a placebo or the real product. Meanwhile, the men were sent to the treadmill daily, where they were to run until exhaustion. Each time, the total running distance, the distance in high-intensity intervals (the distance during the really fast sections), as well as heart rate, oxygen uptake, and lactate levels were measured.
How Anthocyanins Improve Running Performance
While the placebo also had a slight performance-enhancing effect on some runners, all men achieved better results under the supplement intake. Interestingly, these varied greatly. One man achieved a 38 percent higher distance, with the average performance advantage being 8 percent. Measurements of heart rate, VO2max, and lactate showed no difference between the two measurement periods. Therefore, the performance increase is likely not due to changes in cardiovascular stress. The researchers suspect better muscle blood flow, which was not measured. Their conclusion: While it is not a miracle cure, most athletes can expect a temporarily increased performance during intense training.
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Strengths and Weaknesses of the Study
Randomized, double-blind crossover studies like this offer several advantages: They reduce bias, are reproducible, and practical. This means athletes can at least partially verify the results in their daily lives. However, the study group in this case was very small, with 16 fit men. The results, which varied greatly from person to person, do not automatically apply to women, older people, or beginner runners. The short trial period also does not allow conclusions about long-term effects. The exact biological cause of the performance increase remains speculative. Furthermore, the study cannot determine whether other factors from general lifestyle, training, or diet played a role. Also, whether only the extract or the fruits themselves have an effect remains open. Interested runners are left to try a self-experiment.
Should Athletes Opt for an Anthocyanin-Rich Diet? Here’s What the Study Leader Says
Is an expensive dietary supplement necessary for the effect? After all, the valuable anthocyanins are naturally found in numerous foods. FITBOOK asked study leader Prof. Mark Willems for his opinion. His assessment: “If it is indeed the specific amount we chose for our study, it is very likely.” However, there is a lack of research on this. Nevertheless, he recommends incorporating as much fruit and vegetables with the typical blue, red, or black color into the daily diet. Among the biggest “anthocyanin bombs” besides black currants are:
- Elderberries
- Blackberries
- Red cabbage
- Red onions
- Beets
- Eggplants
- Kidney beans
- Purple carrots
Willems also has a hypothesis that may particularly please female athletes: “We have indications that the metabolic reactions in women and men can be similar.”