Health

Can tomato juice lower blood pressure and reduce the risk of heart disease? Here's what the NHS says


Can tomato juice lower blood pressure and reduce the risk of heart disease? Here's what the NHS says
The NHS has responded to 'overenthusiastic' headlines following a new study (Image: Anthony Devlin/PA Wire)

The NHS has given its verdict on claims that drinking tomato juice once a day can reduce a patient's risk of getting heart disease.

It comes after a new study, conducted by health and science institutions in Japan, which suggested that a daily dose of the juice reduces blood pressure and cholesterol.

The research, which was conveniently funded by a Japanese tomato juice producer, involved 500 people who were provided with a year's supply of the drink as part of the study.

Researchers conducted medical examinations at the start and end of the study, with the results eventually published in the Food Science and Nutrition journal.

The findings have since become the focus of media attention, with the NHS having now shared its thoughts on the research.

So what exactly did the researchers uncover? And how have their results been interpreted?

What was the study?

Can tomato juice lower blood pressure and reduce the risk of heart disease? Here's what the NHS says
Researchers investigated whether daily intake of fruit juice made from tomatoes had an health benefits (Image: Shared Content Unit)

This was an observational study, used to compare people before and after receiving 'treatment' - in this case, the treatment was drinking tomato juice.

Researchers enrolled 541 participants, who were provided with as much unsalted tomato juice as they wanted for a year.

The volunteers recorded how much they consumed every day and their diaries were collected every 3 months.

A medical test, including a physical examination and a lifestyle questionnaire, were conducted on participants before and after the study.

This included measuring their blood pressure as well as cholesterol levels.

Researchers then compared these two factors before and after the study to see if they had changed.

What were the results?

Can tomato juice lower blood pressure and reduce the risk of heart disease? Here's what the NHS says
The study uncovered that tomato juice reduced the blood pressure levels of participants by around 3% (Image: Anthony Devlin/PA Wire)

A total of 481 participants completed the satisfactory requirements by the end of the year - with those excluded having not participated in the second medical examination or having not consumed enough tomato juice.

Of those that successfully finished the study, the average consumption of tomato juice was about 1 bottle (200ml) a day.

Researchers found that there was no difference in blood pressure, cholesterol or any other factors measured - such as body mass index - for the overall participant group.

They however found some improvement for the 94 volunteers who had displayed raised blood pressure prior to the study.

There was an average drop of 4.2mmHg (3% decrease) for systolic blood pressure and an average drop of 2.4mmHg (2.9% decrease) for diastolic blood pressure.

The researchers also looked separately at 127 participants who had raised cholesterol at the start of the study.

The results showed an average drop of 5.1mg/dl (3.3% decrease) in LDL cholesterol, after a year of taking tomato juice.

What has the NHS said?

Can tomato juice lower blood pressure and reduce the risk of heart disease? Here's what the NHS says
The NHS said the study had no clear 'clinical significance' (Image: Dominic Lipinski/PA Wire)

The NHS said it is "impossible to tell if the results had anything to do with tomato juice" or if they're related to other factors.

This, it said, casts doubt on whether there's any "clinical significance" to the new research.

The health organisation said that the small sample of Japanese participants may not be representative and is therefore "poor evidence that tomato juice is good for the heart."

It noted that some headlines about the study were "overenthusiastic," particularly those claiming tomato juice could reduce the risk of heart disease.

The NHS added that the study had a number of limitations, including the fact it failed to acknowledge any medical treatment being received by participants - such as statins - which may have been the cause of the reduced cholesterol levels, for example.

It said that tomato juice can be part of a healthy diet, but noted that experts recommend no more than one serving (150ml) of fruit juice a day - due to their high sugar content.


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