The Physiology of Endurance Running Podcast · Dan Nash and Owain Zerilli

Blackcurrants, the unknown super-supplement? - with Dr Sam Shepherd

·1 hr 10 min·4 clips

Blackcurrants increased fat oxidation by about 20% to 30% across several populations.

1. The Physiology of Endurance Running Podcast episode with Dr Sam Shepherd focuses on New Zealand blackcurrants and their effects on metabolism and endurance physiology. 2. Sam Shepherd appears as head of sports science at Precision Fuel and Hydration, with a background that includes the University of Birmingham, Aberdeen, and Liverpool John Moores University. 3. The episode asks what blackcurrant extract is doing to fat oxidation, glycogen storage, and training recovery. 4. Shepherd says his PhD work at Birmingham centered on exercise metabolism and high-intensity interval training. 5. He explains that much of his later work at Liverpool John Moores involved taking muscle samples to study how exercise and nutrition alter muscle metabolism. 6. The blackcurrant work began after an email from Professor Mark Williams at the University of Chichester. 7. Williams had already shown that seven days of blackcurrant capsules could increase fat oxidation in men. 8. Shepherd and his team then tested whether the same response occurred in females. 9. He says blackcurrants are rich in anthocyanins, which are a type of polyphenol found in colorful plants. 10. He notes that one capsule is equivalent to about 83 blackcurrants, which is why the studies use concentrated extracts. 11. Shepherd says the team started from skepticism and used the null hypothesis as the default position. 12. He describes a consistent increase in whole-body fat oxidation of about 20% to 30% across several studies. 13. He says the response appears in healthy, active, overweight, obese, and sedentary participants. 14. In the most recent study, the team used a glycogen-depletion bout and then gave about 8 grams of carbohydrate per kilogram over 36 hours. 15. A pre-exercise muscle biopsy then showed higher glycogen in the blackcurrant condition than in the placebo condition. 16. Shepherd says the mechanism is still unclear, but the finding suggests improved storage or restoration of muscle glycogen. 17. He adds that the team did not see a clear performance benefit in the short cycling test used in that study. 18. The conversation stays applied and technical, with Shepherd often qualifying what the data does and does not show. 19. Athletes interested in recovery between hard sessions, stage racing, or double-threshold training would get the most from this episode. 20. Listeners seeking light chat or simple supplement advice without physiology detail may skip it.

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