A bowl of high-fibre cereal for breakfast can help keep you regular, but new research reveals how much it can do to ward off heart disease, some cancers and diabetes.
A study commissioned by the World Health Organisation, published last week, showed that people who eat lots of high-fibre and wholegrain foods are at a much lower risk of developing heart disease, stroke, diabetes and other chronic diseases.
For every 8 g increase in fibre a day — the amount in, say, two bananas, or a chicken salad sandwich — the researchers found that total deaths and incidence of heart disease, type 2 diabetes and bowel cancer fell by up to 27 per cent. There was also protection against stroke and breast cancer.
New research: People who eat lots of high-fibre and wholegrain foods are at a much lower risk of developing heart disease, stroke, diabetes and other chronic diseases, experts say
The authors of the study, published in The Lancet, believe we should all eat 30g of fibre a day — but 91 per cent of us do not consume anywhere near that amount.
Some experts believe that the importance of having adequate fibre in the diet has been drowned out by other health messages.
‘People have become very focused on cutting back on sugar and salt, and the importance of having adequate fibre in the diet seems to have become overlooked — but it is arguably as important, if not more so, for good health,’ says Professor Nita Forouhi, a public health physician and clinical scientist at the Epidemiology Unit at the University of Cambridge.
Fibre is the indigestible part of plant foods, found in vegetables, fruits, grains and beans. The richest sources include wholegrain bread and cereals, and fruit and vegetables such as berries, pears, oranges, broccoli and sweetcorn.
It speeds up the transit of waste through the colon, protecting against constipation and colon cancer. The fibre in oats, meanwhile, can cut cholesterol, reducing the risk of heart disease and stroke.
Fibre retains its structure in the gut and helps make us feel fuller for longer. A team from Imperial College London is investigating how fibre may hold the key to the obesity crisis.
Their research centres on how bacteria in the gut produce a compound called propionate when they break down dietary fibre.
One theory is that propionate may have a role in controlling hunger pangs, temporarily switching them off. In the future, a supplement version called inulin-propionate ester may be used to help people maintain a healthy weight.
Concern: The authors of the study, published in The Lancet, believe we should all eat 30g of fibre a day — but 91 per cent of us do not consume anywhere near that amount
Fibre is also used as a food source by the friendly bacteria in the gut. ‘These consume fibre and produce by-products called metabolites, which act as messengers to organs such as the heart and brain, and have beneficial effects,’ says Dr Megan Rossi, a dietitian and spokesperson at the British Dietetic Association.
This, she says, may explain the link between high-fibre diets such as the Mediterranean diet and lower rates of heart disease and some mental health conditions.
These metabolites also assist the immune system, which plays a crucial role in the development of cancers. ‘Around 70 per cent of the body’s immune cells reside within the gut and are influenced and interact with the bacteria in the gut, which flourishes on a fibre-rich diet,’ says Dr Rossi.
It’s also thought short-chain fatty acids, produced by gut bacteria from fibre, reduce the risk of inflammatory diseases, heart disease, type 2 diabetes and stroke.
In 2015, the Scientific Advisory Committee on Nutrition recommended that adults should aim to eat 30g of fibre per day. On average, women in the UK consume around 17g a day compared to 21g for men.
One issue is that the majority of Britons still eat white processed carbohydrates, such as rice, pasta, and white bread, which contains less than half the fibre of wholemeal bread.
These habits need to change, says Professor Forouhi. ‘This latest research and other research all highlight the benefits from fibre. We need to take notice.’