Does a pomegranate a day keep your blood pressure at bay?

Pomegranate (Punica granatum) is a fruit-bearing shrub native to the Middle East but is cultivated widely. Once you’ve managed to successfully peel away the bitter pith, the edible seeds (arils) make for a sweet and tasty treat. Aside from making a delicious salad topping, pomegranates are believed to have a number of health benefits. They are rich in fibre, vitamins and minerals, and drinking pomegranate juice has been reported to reduce blood pressure. If this effect is true, pomegranates could help to reduce one of the most important preventable causes of premature ill health and death. We decided to investigate this claim further…

A seed of knowledge

How could pomegranates reduce blood pressure? Pomegranates are believed to reduce blood pressure through reducing levels of Angiotensin converting enzyme (ACE). ACE is a protein that plays an important role in controlling blood pressure through controlling the size of blood vessels in the body.

The juicy details

We systematically reviewed the published scientific literature about pomegranate and its effect on systolic blood pressure (the pressure in the blood vessels when the heart pumps) and diastolic blood pressure (the pressure in the blood vessels when the heart relaxes). We included randomised clinical trials that tested the effect of pomegranate (juice, capsules, or extract) on people aged 16 years and above.

We ended up with eight studies in the review. Five of the studies compared pomegranate juice with a control beverage, and three compared pomegranate capsules with a dummy. The study durations ranged from two weeks to 18 months, and the quality of the studies was variable.

Systolic blood pressure

Two studies found that pomegranate significantly reduced systolic blood pressure in the pomegranate group compared to the control group. A further study, however, did not find that there was a difference between the two groups. Five studies did not provide enough statistical information to determine the effect of pomegranate on systolic blood pressure compared with a dummy.

Diastolic blood pressure

Two studies found that pomegranate significantly reduced diastolic blood pressure in the pomegranate group compared to the control group, but a further two studies did not find a difference between the two groups. Four studies did not provide enough statistical information to determine the effect of pomegranate on diastolic blood pressure compared with a dummy.

Adverse events

The two studies that reported data on adverse events didn’t find any harms associated with pomegranate consumption.

A bitter aftertaste?

The evidence for benefit of pomegranate consumption on blood pressure is uncertain. In spite of this, pomegranate lovers might cite that fruit consumption is considered part of a healthy diet and actively promoted to all. Any benefits on blood pressure would be considered an added bonus.

We’d like to see more trials performed of high quality and longer duration, o that we can make robust conclusions about the effect of pomegranate on blood pressure. But for the time being, it seems as though we’ll have to keep swallowing our blood pressure pills. Should you decide to wash them down with a glass of pomegranate juice it may not do your blood pressure any good, but it shouldn’t do you any harm either.

Dr Oghenekome Gbinigie; MA (Cantab), MB BChir, MRCGP, DRCOG, DfSRH. Academic GP, Nuffield Department for Primary Care Health Sciences, University of Oxford.

Dr Igho Onakpoya; MD; MSc. DPhil student, Nuffield Department for Primary Care Health Sciences, University of Oxford.

Read the full article here: Gbinigie Oghenekome A., Onakpoya Igho J., Spencer Elizabeth A., Evidence for the effectiveness of pomegranate supplementation for blood pressure management is weak: a systematic review of randomized clinical trials, Nutrition Research (2017), doi: 10.1016/j.nutres.2017.07.007

Image credit: http://maxpixel.freegreatpicture.com/Sweet-Plants-Nature-Pomegranate-Red-Exotic-Fruit-1323080