100% grapefruit juice and health effects

Grapefruits are rich in flavonoids such as naringenin, which is the predominant flavanone in grapefruit. Naringenin and other flavonoids have been linked in observational studies with health benefits such as reduced risk of subjective cognitive decline because of the effects they can have on body systems such as the circulatory system[1].

A systematic review and meta-analysis of randomised controlled trials in 2017 evaluated the evidence for grapefruit juice, body weight and cardiovascular disease [2]. The results concluded that grapefruit juice had no significant effects on body weight but did provide a small but significant reduction in systolic blood pressure. The authors conclude that “Grapefruits could cause significant reductions in systolic blood pressure”.

A recent randomised controlled trial gave post-menopausal women either grapefruit juice or a flavanone-free control drink for 6 months [3]. Researchers found that grapefruit juice modified gene and microRNA expression in particular immune cells, suggesting an ability to regulate inflammation, immune response and cell interaction. This may point to a mechanism for how grapefruit juice has potential beneficial effects in the body.

This study builds on a randomised crossover trial conducted in 2015 that assessed the effects of 340ml/day grapefruit juice or matched control on vascular protection in 48 post-menopausal women [4]. This study found that grapefruit juice gave a significant reduction in arterial stiffness after 6 months of intake.

In conclusion, flavanones found in grapefruit juice could influence inflammation, the immune system and how our cells interact leading to positive health effects such as improved circulation.

References

1 Yeh TS et al. (2021) https://pubmed.ncbi.nlm.nih.gov/34321362/

2 Onakpoya I et al. (2017) https://pubmed.ncbi.nlm.nih.gov/25880021/

3 Krga I et al. (2022) https://pubmed.ncbi.nlm.nih.gov/35694160/

4 Habauzit V et al. (2015) https://pubmed.ncbi.nlm.nih.gov/26016866/