Eating just one cup of raw vegetables daily, such as leafy greens like spinach, boosts your cardiovascular health, a new study reveals.
In a sample of over 50,000 people, the biggest eaters of nitrate-rich vegetables had lower blood pressure and up to 26 per cent lower risk of heart disease, experts found.
Just one cup is what the researchers call a ‘moderate’ intake, and should be an achievable goal even for people who don’t like their greens.
Dietary nitrates – found in leafy green vegetables and especially rich in beets too – are converted to nitric oxide by bacteria in the oral cavity and stomach.
It’s already known that nitric oxide, a gas produced naturally by the body and carried in the blood, helps blood vessels expand, thereby lowering blood pressure.
The new research found that by eating just one cup of nitrate-rich vegetables each day people can reduce their risk of heart disease
– Leafy greens: Kale, arugula, chard, spinach.
– Chinese cabbage
High blood pressure – also known as hypertension – is one of the main risk factors of cardiovascular diseases (CVD), such as coronary artery disease and heart attacks.
Cardiovascular diseases are the number one cause of death globally, taking around 17.9 million lives each year.
‘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 study author Dr Catherine Bondonno from Edith Cowan University (ECU) in Western Australia.
‘One cup of raw vegetables is equivalent to half a cup of cooked vegetables in serving size and therefore nitrate content.’
Interestingly, there didn’t appear to be any additional health benefits from eating more than the optimum amount (one cup a day).
‘People don’t need to be taking supplements to boost their nitrate levels because the study showed that one cup of leafy green vegetables each day is enough to reap the benefits for heart disease,’ Dr Bondonno said.
‘We did not see further benefits in people who ate higher levels of nitrate rich vegetables.’
HOW TO MEASURE BLOOD PRESSURE
Blood pressure is a measure of the force that the heart uses to pump blood around the body, and it rises and falls in a cycle with each pulse.
It is measured in units of millimetres of mercury (mmHg), and the reading is always given as two numbers – systolic pressure (the pressure when the heart pushes blood out) and diastolic pressure (the pressure when the heart rests between beats).
The systolic reading represents the maximum blood pressure and the diastolic reading is the minimum blood pressure.
A high systolic blood pressure in one arm alone indicates hypertension.
For those who find it hard to eat vegetables because they don’t like the taste, the scientists say smoothies are OK.
Hacks such as including a cup of spinach in a banana or berry smoothie might be an easy way to boost our intake of nitrate-rich veg, according to Dr Bondonno.
‘Blending leafy greens is fine, but don’t juice them – juicing vegetables removes the pulp and fibre,’ she said.
For the study, researchers examined dietary intake and blood pressure data from over 53,150 people residing in Denmark taking part in the Danish Diet, Cancer and Health Study over a 23-year period.
During the 23 years of follow-up, 14,088 cases of incident CVD were recorded.
Researchers found that people who consumed the most nitrate-rich vegetables had about a 2.5 mmHg lower systolic blood pressure and between 12 to 26 per cent lower risk of heart disease.
‘The greatest reduction in risk was for peripheral artery disease (26 per cent), a type of heart disease characterised by the narrowing of blood vessels of the legs,’ Dr Bondonno said.
‘However, we also found people had a lower risk of heart attacks, strokes and heart failure.’
Participants with the highest vegetable nitrate intake were more likely to be female, have a slightly lower body mass index (BMI), be more physically active, have never smoked, and have a higher degree of education and income.
Those with a high vegetable nitrate intake also tended to consume more fish, vegetables, fruit, fibre, flavonoids and less processed meat than those with a low vegetable nitrate intake.
The study, published in the European Journal of Epidemiology, adds to growing evidence linking vegetables generally and leafy greens specifically with improved cardiovascular health and muscle strength.
Adding some leafy greens to your breakfast smoothies could be a useful ‘hack’ to reap the health benefits
In March this year, Edith Cowan University researchers reported that one cup of leafy green veg a day helps to boost muscle function.
The team examined data from 3,759 participants taken over a 12-year period, including details of their diets, their lower limb strength, and walking speeds.
Their analysis revealed that people with the highest regular nitrate consumption had 11 per cent stronger lower limbs, and four per cent faster walking speeds than those with the lowest nitrate intake.
‘We know from previous research that nitric oxide is a vasodilator, which means that it widens your blood vessels, potentially allowing greater blood flow to your muscles,’ study author Dr Marc Sim said at the time.
NITRATES IN ROOT VEG AND LEAFY GREENS HELP LOWER BLOOD PRESSURE
Asked what nitric oxide gas is, many people might suggest it’s ‘hippy crack’, the legal high that’s landed so many Premier League footballers in trouble.
In fact that’s nitrous oxide. But thanks to some recent and dramatic discoveries, nitric oxide could soon be far better known – for its many health benefits, rather than any dangers.
It’s already known that nitric oxide, a gas produced naturally by the body and carried in the blood, tells your blood vessels to expand, thus lowering blood pressure.
That’s why beetroot in particular is so good for blood pressure – the body converts the nitrites in this veg into nitric oxide.
Researchers have since found nitric oxide does a lot more, including helping you to sleep and fight off infections.
And it turns out we have large, totally unexpected stores of it under our skin, and our blood cells don’t work properly without it.
Boosting our nitric oxide levels by eating more veg such as celery, or exercising more could help prevent diseases including diabetes and cancer.
Until a few years ago, no one knew that blood cells even carried nitric oxide.
Now we realise that it plays a vital role in ensuring cells get the oxygen they need, as research at the Case Western Reserve University School of Medicine in Cleveland in the US found in 2015.
‘Cardiologists have always assumed that if your blood was carrying a normal amount of oxygen, the gas would automatically get into cells,’ Jonathan Stamler, the lead researcher and a professor of medicine, told Good Health. ‘Now it looks like that was wrong.
‘What we’ve discovered is that the oxygen carried in blood cells can’t be delivered into the body’s cells unless it comes with nitric oxide.
‘When you put red blood cells and blood vessels together in the lab, the blood vessels close up.
‘We eventually worked out that the cells were missing nitric oxide. It was lost when you took the blood cells out of the body.’
A lack of the gas could cause problems generally linked to poor blood flow, such as heart attack, heart failure, stroke, damage to the kidneys and poor circulation in the legs.
But the discovery also alerted Professor Stamler to a problem with transfusions. ‘
Stored blood loses its nitric oxide, which means that transfusions generally fail to deliver the oxygen that cells may desperately need,’ he said.
‘Transfusions do help when there’s been massive blood loss, but in most cases there is only modest blood loss.
‘Cardiologists have long been puzzled by how patients could have enough oxygen in the blood, but lack it in the cells.
‘Now we have the answer.’