Eating up to 30 grams of naturally-occurring dietary fibre -- such as whole grains, pulses, vegetables and fruits -- daily may prevent the risks of developing non-communicable diseases, finds a review of studies published in the journal The Lancet.

The results suggest a 15-30 per cent decrease in all-cause and cardiovascular-related mortality; and reduced incidence of coronary heart disease, stroke, Type-2 diabetes and colorectal cancer by 16-24 per cent. Increasing fibre intake is associated with lower bodyweight and cholesterol, compared with lower intake or synthetic and extracted fibre.

"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," said Professor Jim Mann, from the University of Otago, New Zealand.

"Fibre-rich whole foods that require chewing and retain much of their structure in the gut increase satiety and help weight control and can favourably influence lipid and glucose levels. "The breakdown of fibre in the large bowel by the resident bacteria has additional wide-ranging effects including protection from colorectal cancer," Mann said.

Protection against stroke, and breast cancer also increased. Consuming 25-29 grams each day was adequate but the data suggest that higher intakes of dietary fibre could provide even greater protection. The researchers included 185 observational studies and 58 clinical trials involving 4,635 adult participants. 

The study also found that diets with a low glycaemic index and low glycaemic load provided limited support for protection against Type 2 diabetes and stroke only. Foods with a low glycaemic index or low glycaemic load may also contain added sugars, saturated fats, and sodium. However, high intakes might have ill-effects for people with low iron or mineral levels for whom high levels of whole grains can further reduce iron levels, the researchers noted.