New research has uncovered a link between higher intakes of fibre and a reduction in the risk of several diseases.
Researchers at the University of Otago in New Zealand looked at analyses and clinical trials conducted over nearly 40 years.
They found a 15 to 30% decrease in deaths and incidence of coronary heart disease, stroke, type two diabetes and colorectal cancer, when comparing the highest dietary fibre consumers with the lowest.
For every 1,000 participants in the studies, the impact of consuming higher fibre translated into 13 fewer deaths and six fewer cases of coronary heart disease compared to those consuming less fibre.
Lead author Dr Andrew Reynolds said the results give convincing evidence that we should increase fibre intake, and replace refined grains with whole grains.
"Our research indicates we should have at least 25 to 29 grams of fibre from foods daily, although most of us currently consume less than 20 grams of fibre daily.
"Practical ways to increase fibre intake is to base meals and snacks around whole grains, vegetables, pulses and whole fruits."
Co-author Professor Jim Mann said the study findings are significant.
"This study is essential as there is increased public confusion over what to base our meal choices on, and the impact our dietary choices have on our risk of certain diseases.
"While we all knew that dietary fibre was good for us we didn't know the extent to which the old mantra was true".
File photo of fresh vegetables | Image: David Davies/PA Wire/PA Images
The study, published in The Lancet, looked at 58 clinical trials and 185 prospective studies from all over the world that considered the role of fibre, whole grains, dietary glycaemic index, and glycaemic load on health.
Professor Mann said the study is unique in that it has examined a range of indicators of carbohydrate quality and many disease outcomes.
The researchers found people who increased the amount of fibre in their diet had lower bodyweight, and total cholesterol.
"We also found an overwhelmingly positive effect, with high fibre diets being protective against heart disease, diabetes, cancers and measures of mortality", Prof Mann added.
The results also showed diets with a low glycaemic index and low glycaemic load provided limited to no benefit.
Foods with a low glycaemic index or low glycaemic load can also contain added sugars, saturated fats and sodium.
Prof Mann said this may account for the links to health being less clear.
Dr Reynolds said the team also looked at whole grain intake, which showed protective benefits.
"There is no surprise there, as wholegrains such as oats and chunky whole grain bread can be major sources of fibre in the diet.
"Fibre and whole grains are important physiologically, metabolically, and even to gut microbiome. Eating high fibre and whole grain foods is of a clear benefit to our health by reducing the occurrence of a surprisingly broad range of important diseases"
The study was commissioned by the World Health Organisation (WHO).