A study of nearly 30 000 people has shown that eating just 26 g of fibre per day can reduce the risk of developing type 2 diabetes by a fifth.
The authors of InterAct, a case–control substudy of the multinational EPIC (European Prospective Investigation into Cancer and Nutrition) study, compared dietary fibre intake between people who developed type 2 diabetes over 11 years of follow-up (n=11 559) with a random sample (n=15 258, including 729 of the cases of incident diabetes) recruited from the same study cohort.
After adjustment for lifestyle and other dietary factors, total dietary fibre intake was associated with a lower risk of developing diabetes. Comparing participants in the uppermost quartile (energy-adjusted total fibre intake, >26.4 g/day) with those in the lowest quartile (<18.9 g/day), the hazard ratio was 0.82 (95% confidence interval, 0.69–0.97). Cereals (including wholemeal bread) were the main source of fibre in most of the eight countries, followed by fruits and then vegetables. In subanalyses, cereal and vegetable fibre had similar associations with diabetes risk as total fibre; however, consumption of fruit fibre did not improve the risk.
Adjustment for BMI accounted for 50% of the association between fibre and diabetes risk, suggesting that much of the effect was mediated by reductions in BMI. Commenting on the study, Naveed Sattar, Professor of Metabolic Medicine at Glasgow University, said: “This very large and powerful study provides yet more evidence for a potential link between higher fibre intake and lower risk of diabetes but it adds a twist to the evidence – namely that higher fibre intake seemed to be associated with lower body mass. In other words, eating more fibre may help lower diabetes risk by helping individuals keep their weight in check.”
Dagfinn Aune, a Ph.D. student at Imperial College London and one of the study authors, offered some potential mechanisms behind dietary fibre’s effects on BMI, including people feeling physically full for longer, prolonged release of hormonal signals, slowed down nutrient absorption and altered fermentation in the large intestine. Other suggested mechanisms affecting type 2 diabetes risk directly included improving control of blood sugar, decreasing insulin peaks after meals and increasing the body’s sensitivity to insulin.
The study can be read in full in Diabetologia here.
