High-fibre diet cuts risk of death from cancer, stroke and heart disease by up to a third, major study finds

Most people around the world do not eat the amount of fibre needed to prevent key life-threatening illnesses, new research suggests.

A nutritional review, which includes 185 studies and 58 clinical trials conducted over nearly 40 years, found that eating at least 25g to 29g of fibre per day was linked to a 15 to 30 per cent reduction in rates of life-threatening cancers, strokes and heart disease.

For every 1,000 participants, researchers found that eating more fibre translated into 13 fewer deaths and six fewer cases of coronary heart disease.

But worldwide the majority of people consume less than 20g of fibre a day.

UK guidelines, in place since 2015, recommend that people eat 30g a day, yet only 9 per cent of British adults meet the target.

In the US rates of consumption are even worse, with the average adult eating just 15g of fibre a day.

Experts found that for every 8g increase in fibre consumption, total deaths from coronary heart disease, type 2 diabetes and colorectal cancer plummeted by 5-27 per cent.

Researchers did not find any risks associated with eating fibre but the nutritional review’s authors noted that consuming lots of it could have ill-effects for people with low iron or mineral levels.

Whole grains, which are high in fibre, can further reduce iron levels.

The review’s authors also emphasised that their results mainly related to fibre rich foods and not synthetic fibre, such as powders, which can be added to meals.

“This study effectively re-endorses that the UK government advice to consume 30g fibre per day is pretty spot on,” said Nita Forouhi, a professor at Cambridge University’s MRC Epidemiology Unit.

“The onus is on individuals themselves, as well as public agencies, to make it happen, as average fibre intakes remain woefully low at a population level in the UK.

“This research did not study total carbohydrate intakes specifically, but its findings do imply that, though increasingly popular in the community at large, any dietary regimes that recommend very low-carbohydrate diets should consider the opportunity cost of missing out on fibre from whole grains.

“This research confirms that fibre and whole grain intakes are clearly important for longer term health.”

The nutritional review was commissioned by the World Health Organisation, authored by researchers from the University of Otago and is published in The Lancet.