Vegetables may be good for you, but eating a lot of them is unlikely to reduce your risk of a heart attack or stroke, a large UK study suggests.
What else we eat, how much exercise we do and where and how we live may have more of an impact, the researchers say.
But they emphasise that a balanced diet helps reduce the risk of many diseases, including some cancers.
Eating at least five portions of fruit and vegetables every day is recommended by health advisers, including the NHS.
The study, from the universities of Oxford and Bristol and the Chinese University of Hong Kong, asked nearly 400,000 people who are taking part in the UK Biobank study to fill in a questionnaire about their diet, including the quantity of cooked and raw vegetables they ate each day.
On average, people said they ate two heaped tablespoons of raw vegetables, three of cooked vegetables and five in total per day.
Their health, and any heart problems that led to hospital treatment or death, was then tracked over the next 12 years.
Rich in fibre
Although the risk of dying from cardiovascular disease was around 15% lower for those eating the most vegetables – particularly those eating lots of raw veg – compared with those eating the least, the researchers said this could all be explained by other factors.
These included people’s lifestyles – for example, whether they smoked and how much alcohol they drank – as well as their jobs, incomes and overall diet.
As a result, they said their study did not find evidence of “a protective effect of vegetable intake” on how often heart and circulatory problems occurred.
Why eat five a day?
According to NHS advice, fruit and veg are a good source of vitamins, such as folate, and minerals, such as potassium
They also contain fibre, which can help keep your gut healthy, prevent digestion problems and reduce risk of bowel cancer
They can help to reduce your risk of heart disease, stroke and some other cancers
Fruit and vegetables contribute to a healthy, balanced diet
And they are usually low in fat and calories (provided you do not fry them or roast them in lots of oil)
Oils and fat used in cooking may also increase intake of sodium and fats, which are known risk factors for heart problems.
People eating a high-vegetable diet may eat fewer calories and less fat, while also consuming more vitamins and anti-oxidants, which can prevent damage to cells.