Having blood sugar and insulin rise rapidly after a meal has been linked to a number of metabolic problems. Products, like crackers, cookies or bread, that cause such a rapid increase are termed high-glycemic index foods. Certain other foods, such as vinegar and cinnamon, can blunt the rapid rise in blood sugar after eating a high-glycemic index food. What about pomegranate juice?
Studying Pomegranate Juice:
Now, British scientists have found that pomegranate juice, though not pomegranate extract, can reduce the bump in blood sugar from bread by approximately one third (Kerimi et al, American Journal of Clinical Nutrition, Dec. 2017). They performed three separate randomized controlled studies with a cross-over design on 16 volunteers. Through these experiments, they compared how much blood sugar rose with bread alone (using a placebo beverage) to the rise with bread and pomegranate juice. Peak blood sugar was 25 percent lower with juice. Pomegranate juice lowered the amount of time that blood sugar was elevated by 33 percent. This is statistically significant.
The third study utilized regular fruit juice of similar acidity to pomegranate. After all, if vinegar reduces blood sugar spikes, perhaps there is something about acid that makes a difference. They found that ordinary juice did not reduce the rise in blood sugar.
Will the Effect Last?
According to the scientists, gut bacteria may act on some pomegranate polyphenols. The microbial metabolites may help control sugar uptake by liver cells. Perhaps this would extend the blood-sugar-controlling benefits of pomegranate juice for longer periods of time.
A systematic review and meta-analysis of 16 different randomized controlled trials did not find any consistent impact of pomegranate on blood sugar (Huang et al, Nutrition Journal, Oct. 6, 2017). The interventions did not seem to affect insulin levels, either. We don’t know, however, whether these studies were utilizing extracts or juice. The study reported above found that extract was not effective.
Other Benefits of Pomegranate Juice:
We have reported separately on a meta-analysis demonstrating that pomegranate polyphenols in juice can help control blood pressure. The average dose in the eight studies analyzed was approximately one cup a day.
Another study of 30 people with metabolic syndrome found that those who drank two cups of pomegranate juice every day had lower blood pressure at the end of one week (Moazzen & Alizedeh, Plant Foods for Human Nutrition, June 2017). An important measurement of inflammation, hs-CRP, was also lower.