Adding a handful of spinach to your salad, risotto or smoothie could ward off heart disease, research suggests.
Heart disease is behind more than one in four deaths in the UK.
Scientists from Edith Cowan University in Perth, Australia, analysed more than 53,000 people over 23 years.
Results suggest those who ate a cup of raw – or half a cup of cooked – green leafy vegetables, like spinach, a day were up to 26% less likely to develop heart disease.
"Our results have shown that by simply eating one cup of raw (or half a cup of cooked) nitrate-rich vegetables each day, people may be able to significantly reduce their risk of cardiovascular disease," said lead author Dr Catherine Bondonno.
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With "evidence-based" treatments a "global research priority", the Edith scientists set out to uncover the "optimal diet" for cardiovascular health.
The team analysed participants of the Danish Diet, Cancer, and Health Study, none of whom had heart disease at the start of the trial.
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Over the next 23 years, more than 14,000 cardiovascular disease "cases" were recorded.
The results – published in the European Journal of Epidemiology – reveal the participants with the highest intake of vegetable nitrate, a nutrient found in green leafy vegetables and beetroot, had lower blood pressure than those who consumed the least.
Eating more vegetable nitrate was also linked to a reduced risk of heart disease, with the benefit "plateauing at moderate intakes", around 60mg (a moderate serving) a day.
Overall, those with a moderate intake were 15% less likely to develop heart disease than the participants who consumed the least amount of vegetable nitrate, at around 23mg per day.
A moderate intake was specifically associated with a 12% lower risk of ischaemic heart disease, caused by narrow arteries depriving the vital organ of oxygen.
This consumption was also linked to 15% reduced odds of heart failure, when the organ is unable to pump blood around the body efficiently, and a 17% lower risk of an ischaemic stroke.
Most markedly, a moderate vegetable nitrate intake was associated with a 26% lower risk of being hospitalised with peripheral artery disease (PAD), when blood flow to the legs is restricted. In severe cases, PAD can affect the arteries supplying the heart and brain.
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Consuming more than a moderate intake was not linked to any additional benefits.
"People don't need to be taking supplements to boost their nitrate levels because the study showed one cup of leafy green vegetables each day is enough to reap the benefits for heart disease," said Dr Bondonno.
"We did not see further benefits in people who ate higher levels of nitrate-rich vegetables."
Adding a handful of spinach to a banana or berry smoothie may be a good way to up your intake, but be sure to whizz the vegetable gently.
"Blending leafy greens is fine, but don't juice them," said Dr Bondonno. "Juicing vegetables removes the pulp and fibre."
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