The 6th article in our small changes with big effects series.
Eat plenty of beetroot and garlic to keep your blood pressure down
image ©Jason Raish
An ideal healthy systolic blood pressure is between 90 and 120mmHg, so what can you do if your blood pressure is slightly too high? Well, losing a bit of weight, exercising more and stopping smoking will all help, but so can consuming certain foods – or at least that is what we discovered on Trust Me, I’m A Doctor, when we did a small experiment with Dr Andy Webb at King’s College, London, a few years ago.
We wanted to test the claims that beetroot, garlic and watermelon could lower blood pressure. All three foods are said to work by boosting levels of nitric oxide in the body, which in turn causes blood vessels to open up and blood pressure to fall.
So what happened? Well the average systolic blood pressure of the volunteers at the start was 133.6mmHg. On the beetroot diet, this went down to 128.7mmHg. Consuming two cloves of garlic a day gave a similar result (129.3mmHg).
A fall in blood pressure of around 5mmHg doesn’t sound a lot, but studies suggest that if was maintained it would translate into a reduction of the risk of stroke and heart attack of around 10 per cent.
I love garlic and I am happy to pile my plate with beetroot and other nitrate-rich veg, such as rocket, spinach, chard and broccoli.
Read Dr Mosley’s full advice on lowering your blood pressure
BBC – The big blood pressure experiment
Dr Chris van Tulleken sets out to test the health claim made for three foods – beetroot, garlic and watermelon. It’s said they can all reduce our blood pressure but what’s the truth? High blood pressure is a major risk factor for heart disease, the U.K.’s biggest killer, so if such claims are true then these three foods could be lifesavers.
Dr Andy Webb of Kings College London helped run an experiment to find out what effect these foods really have.
The experiment involved 28 volunteers who all had a systolic blood pressure above 130mm of mercury (the ideal blood pressure for an adult is around 120), and they were divided into three groups. During the first week:-
- Group 1 ate two cloves of garlic every day.
- Group 2 ate two large slices of watermelon a day.
- Group 3 ate two whole beetroots every day.
For the second and third week, each group swapped over so that by the end of three weeks everyone had tried each food.
Each volunteer measured their blood pressure twice a day – morning and evening. Each time they took 3 measurements to calculate an average. It was then possible to see which foods made the biggest difference to blood pressure.
The baseline blood pressure for the group—the average reading taken when everybody was eating and drinking normally – was 133.6 mmHg. On the beetroot diet, this went down to 128.7 mmHg and the garlic gave a similar result (129.3 mmHg). The result in this small study is in agreement with what Dr Webb and others have found in larger studies.
Studies on the links between high blood pressure and heart disease suggest that, if such a drop in blood pressure is maintained, this roughly translates into a reduction of the risk of stroke and heart attack by 10%! Watermelon didn’t have such a strong effect – it reduced systolic blood pressure to 129.8mmHg. This may be because water melon is mainly water- there isn’t much of the active ingredient.
Full details here
Other recommended links:
NHS – Garlic and High Blood Pressure
NHS – Beetroot and High Blood Pressure
Biomedcentral – A review of studies on impact of garlic on blood pressure