Faculty of Natural Sciences Faculty News and events
Naturally Cloudy Apple Juice and Gut Health: Implications for Regenerative Sports Nutrition

Naturally Cloudy Apple Juice and Gut Health: Implications for Regenerative Sports Nutrition

Investigations into the protective effects of apple juice on the intestinal barrier

This is the title of a study investigating the beneficial effects of naturally cloudy apple juice spritzer on the intestinal barrier. The study confirmed the already known positive effects of apple juice spritzer as a natural regeneration drink after physical exertion.

The study ran from 2021 to 2023 and was funded by the Forschungskreis der Ernährungsindustrie e.V. (FEI) under the "Industrielle Gemeinschaftsforschung" (IGF, project AIF 21925 N) funding programme.
The project was carried out by an interdisciplinary, inter-university research team consisting of apl. Prof Patrick Diel, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Prof Tuba Esatbeyoglu, Institute of Food Science and Human Nutrition, Leibniz University Hannover, and Prof Ina Bergheim from the University of Vienna.
In addition, research in Hanover was supported at faculty level on an interdisciplinary basis. In collaboration with the Institute of Organic Chemistry, Dr Gerald Dräger, the apple juice constituents in the juices and cell culture samples were analysed, and the working group of Prof Dr Oliver Plettenburg complemented the expertise on the intestinal barrier with previous studies on intestinal permeability. In addition, a number of master's theses were carried out as part of the project, including one at the University of Würzburg, where the cell culture model and associated measurement methods were established through preliminary testing supervised by Prof Leane Lehmann.  Some further measurements of apple juice constituents were carried out in cooperation with industry (riha WeserGold).

Secondary plant compounds - especially polyphenols

The interactions between diet, physical stress and gut health were analysed in more detail. The research project showed that naturally cloudy apple juice, especially in the form of spritzers, can significantly reduce the negative effects of physical stress on the intestinal barrier.
The intestinal barrier acts as a critical mediator between our body and the outside world, absorbing nutrients while simultaneously fending off pathogenic bacteria. The integrity of this barrier is essential for maintaining overall health. Previous research has shown that both physical activity and diet have a direct impact on the functioning of the gut barrier. Extreme endurance exercise and certain diets can weaken barrier function, while consuming sugar after intense exercise can promote recovery, but slows the regeneration of the intestinal barrier.

Health benefits: beyond rehydration

This discovery highlights the importance of naturally cloudy apple juice spritzers as a natural and effective way to support gut recovery after exercise.
Thanks to the close collaboration between the three institutions involved, the research team was able to gain significant insights. The results, which were recently presented at the annual conference of the German Nutrition Society, show that naturally cloudy apple juice not only has a rehydrating effect, but also supports the regeneration of the intestinal barrier after physical activity.
This study highlights the importance of interdisciplinary research and collaboration between different universities and institutes. It also shows the importance of understanding and further researching the health effects of the foods and beverages we consume on a daily basis.