A daily sandwich could shrink your waist, lower cholesterol and cut the risk of complications that can lead to a heart attack, a new study suggests.
Researchers discovered that eating the equivalent to two large slices of wholegrain bread per day was associated with a range of heart health benefits – including weight loss.
Scientists made the discovery after analysing all existing research – including 87 clinical trials – linking wholegrain foods to cardiovascular health.
Wholegrain is an umbrella term for food made using all parts of the grain, which are typically lost during processing.
Along with wholegrain bread, other examples include porridge oats, as well as wholewheat pasta and brown rice – healthier alternatives to regular pasta and white rice.
Researchers found that just 48g of wholegrain daily – roughly the amount in two large slices of brown bread or a bowl of oats – could improve heart health.
The biggest improvements, however, were seen when intake jumped to between 60g to 100g a day – around four large slices.
This level of consumption brought the greatest cuts to high blood pressure, so-called bad cholesterol and harmful blood fats.
A daily sandwich could shrink your waist, lower cholesterol and cut the risk of heart attack, a study has found
Experts say the findings reveal a ‘simple, accessible and affordable’ way for Britons to tweak their diets and reduce the likelihood of falling victim to some of the UK’s biggest killers.
Foods made from whole grains have long been associated with protecting against disease such as type 2 diabetes.
This is because they undergo less processing than counterparts, like white bread, for example, according to cholesterol charity Heart UK.
This means they retain key nutrients like fibre, B vitamins, iron, zinc, magnesium, healthy unsaturated fats and plant compounds known as phytonutrients.
However, researchers wanted to investigate the exact quantity of whole grains that benefits heart health.
‘This left an important practical question unanswered: how much whole grain should people eat to meaningfully improve cardiovascular health?’ said Dr Helda Tutunchi, an associate professor in nutritional sciences at the Tabriz University of Medical Sciences in Iran, and study lead.
To find out, the team analysed data from more than 6,500 people spanning Asia, Europe, the US, Canada and Brazil.
The findings were published in the European Heart Journal.
Researchers discovered that consuming just 48g of whole grains per day was linked to fat loss of roughly 0.2kg – or around half a pound – on average.
It was not possible to determine how quickly the weight loss occurred because the studies analysed lasted anywhere from two weeks to two years.
The scientists also found that waist size reduced by around 0.22 centimetres after consuming just 48g a day.
Having a smaller waist size – and thus less visceral fat, which gathers around the organs – has been linked to a reduced risk of disease like type 2 diabetes and cancer.
Total cholesterol levels also fell by around 0.10 millimoles per litre (mmol/L), they found.
According to the NHS, Britons should aim to have a total cholesterol level of 5mmol/L.
Researchers said the reduction was largely driven by a drop in low-density lipoprotein, or so-called ‘bad’, cholesterol, which fell by around 0.07 mmol/L.
The NHS target for this is a reading below 4mmol/L.
This type of cholesterol can cause fatty deposits to build up in the arteries and block blood flow, raising the risk of heart attack and stroke.
Triglycerides – a type of blood fat which, when high, can drive heart disease – also dropped by 0.04 mmol/L. A healthy reading for this metric is below 1.7mmol/L.
Meanwhile, systolic blood pressure – the top number in a reading which measures the pressure of the blood against the arteries when the heart beats – dropped by 0.82 millimeters of mercury (mmHg).
The NHS recommends that Britons eat whole grain foods for various reasons, including increasing intake of fibre – an important nutrient for gut health. Whole grains are also said to make people feel fuller for longer, helping with weight loss.
In the study, the biggest boost was seen among those who ate 60g to 100g of whole grains per day.
At this level of consumption, the reduction in blood pressure was three times greater.
Meanwhile, total cholesterol dropped by 0.21 mmol/L, LDL cholesterol by 0.16 mmol/L and triglycerides by 0.08 mmol/L.
The researchers stressed that they did not measure ‘cardiovascular events’ – such as heart attacks and stroke – directly. This means longer-term studies are needed to analyse whether whole grains reduce the risk of this happening.
However, the findings did show clear improvements in several risk factors associated with the complications.
‘Our findings provide a practical indication of the amount of wholegrain that may be needed to achieve meaningful improvements in cardiovascular risk factors,’ said Dr Tutunchi.
‘Increasing wholegrain intake is a relatively simple, accessible and affordable dietary strategy that can complement other lifestyle and medical interventions.’
