Dundee University research has helped prove that a high fibre diet can significantly reduce the risk of heart disease and stroke.
Research published in The Lancet reveals people who eat at least 25g of fibre a day are far less likely to suffer heart disease, stroke, type 2 diabetes or colorectal cancer than those with a low-fibre diet.
Observational studies and clinical trials carried out over nearly 40 years suggest a 15-30% decrease in all-cause and cardiovascular related mortality when comparing people who eat the highest amount of fibre to those who eat the least.
Eating fibre-rich foods also reduced incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16-24%.
Per 1,000 participants, the impact translates into 13 fewer deaths and six fewer cases of coronary heart disease.
In addition, a meta-analysis of clinical trials suggested that increasing fibre intake was associated with lower body weight and cholesterol, compared with lower intakes.
The study was commissioned by the World Health Organisation to inform the development of new recommendations for optimal daily fibre intake and to determine which types of carbohydrate provide the best protection against non-communicable diseases (NCDs) and weight gain.
Most people worldwide consume less than 20 g of dietary fibre per day.
In 2015, the UK Scientific Advisory Committee on Nutrition recommended an increase in dietary fibre intake to 30 gper day, but only 9% of UK adults manage to reach this target.
In the US, fibre intake among adults averages 15 g a day. Rich sources of dietary fibre include whole grains, pulses, vegetables and fruit.
John Cummings, emeritus professor of experimental gastroenterology at Dundee University’s school of medicine said: “This is a defining moment in the fibre story.
“The work that we have done particularly on fibre and the gut micro flora (microbiome), in Cambridge and in recent years in Dundee, means we have enough evidence from population studies, human experimental work and the biochemistry and physiological of fibre to be confident of the clear benefits to health.
“Fibre has come of age as a unique and essential nutrient.”
Professor Jim Mann from Otago University in New Zealand added: “Previous reviews and meta-analyses have usually examined a single indicator of carbohydrate quality and a limited number of diseases so it has not been possible to establish which foods to recommend for protecting against a range of conditions.
“Our findings provide convincing evidence for nutrition guidelines to focus on increasing dietary fibre and on replacing refined grains with whole grains. This reduces incidence risk and mortality from a broad range of important diseases.”
The researchers included 185 observational studies containing data that relate to 135 million person years and 58 clinical trials involving 4,635 adult participants.
They focused on premature deaths from and incidence of coronary heart disease, cardiovascular disease and stroke, as well as incidence of type 2 diabetes, colorectal cancer and cancers associated with obesity.
The authors only included studies with healthy participants, so the findings cannot be applied to people with existing chronic diseases.