Fruit juice and our gut health

We might not immediately think of our gut health when weighing up the pros and cons of enjoying a glass of 100% fruit juice. However, research suggests it’s a drink that could help to keep our friendly bacteria happy.

Substances like polyphenols (bioactive substances found in plants), oligosaccharides (a type of carbohydrate), and fibre (roughage) found in fruit juice may have a prebiotic-like effect. If we think of probiotics as the beneficial bacteria that live in our gut and contribute to overall health, prebiotics are the food supply for those probiotics.[1]

A 2017 study published in Scientific Reports[2] tested the theory that changes in the gut bacteria play an important role in health benefits linked to juice-based diets. During the trial, 20 healthy adults only consumed vegetable/fruit juices for three days. This was followed by two weeks of eating their usual diet.

On the fourth day of the study, the researchers noted an increase in the ‘good bacteria’ bacteroidetes (linked to a balance of gut bacteria, maintenance of the gut barrier, and brain-immune health) and cyanobacteria (linked to the regulation of blood lipids, blood pressure, and blood sugar). They also observed a decrease in the ‘bad bacteria’ firmicutes (linked with adverse effects on glucose levels and fat metabolism) and proteobacteria (linked to metabolic disorders and inflammatory bowel disease) in stool samples. What’s more, the participants experienced a small but statistically significant reduction in body weight which lasted the full 17 days.

More specifically, flavanones, a type of polyphenol found in citrus fruits, have been shown to provide gut health benefits. A study in Nutrients[3] showed that flavanones can affect the makeup and activity of the gut bacteria. While researchers haven’t yet uncovered the exact reasons why, flavanones have been shown to help strengthen the intestinal barrier and reduce inflammation in the gut.

Evidence on this topic is still emerging but suggests that a daily glass of 100% fruit juice can help to maintain the right balance of different types of bacteria in the gut and, therefore, support overall health.

[1] Davani-Davari D et al (2019). https://doi.org/10.3390/foods8030092

[2] Henning SM et al (2017). https://doi.org/10.1038/s41598-017-02200-6

[3] Stevens Y et al (2019). https://doi.org/10.3390/nu11071464