SCOTS must dramatically increase their fibre intake to reduce deaths from bowel cancer, heart disease and stroke, according to a major new study - but even consuming the recommended five a day of fruit and vegetables will not be enough.

The study, published today in the Lancet, indicates that around 13 deaths in every 1000 people would be prevented if Scots doubled how much fibre they ate.

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It has been described as a “defining moment” in nutrition research after scientists demonstrated substantially lower overall mortality among those with the highest-fibre diets.

In particular, it appeared to protect against coronary heart disease, strokes, bowel cancer, type 2 diabetes, and various obesity-related cancer, including breast and prostate cancer.

The study, which included experts from Dundee University, was commissioned by the World Health Organisation and will underpin new international recommendations for fibre consumption.

The paper concluded that everyone should aim to eat at least 25-29g of fibre a day, yet the average daily intake in Scotland is currently languishing at just 15g according to the latest Food Standards Scotland data.

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Although we have long been told to eat at least five portions of fruit and vegetables every day, Scots are typically consuming just three and a half.

HeraldScotland: Prof John CummingsProf John Cummings

However, Professor John Cummings, an expert in Experimental Gastroenterology at Dundee University’s School of Medicine, admits that even if we did achieve the five-a-day target it would probably only account for around 12g of fibre.

Achieving at least 25g is “huge public health challenge” for Scotland, he said.

Prof Cummings said: “It’s a big change in people’s diets, especially in Scotland. For some people it’s quite a radical change in diet.

“You have to look at getting more wholegrains from breakfast cereal and bread, getting your ‘five-a-day’ - that’s about 400g a day of fruit and vegetables. In Scotland that’s quite challenging.

“Brown rice will be better than white rice, without any question, so that should definitely be considered.

“The other thing that gets forgotten about are nuts, they’re a good source of fibre.”

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As an example, a consumer getting 12g of fibre from five portions of fruit and vegetables could achieve 28g if they also ate two Weetabix biscuits (nearly 4g) for breakfast, two slices of wholegrain bread at lunch (around 3g of fibre), and half a tin of baked beans at dinner (around 7.5g), and snacked on 10g of almonds (1.5g of fibre).

The Lancet study is the most comprehensive investigation to date into the benefits of a high-fibre diet. The researchers examined nearly 250 studies over the past 40 years involving tens of thousands of 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: breast, endometrial, oesophageal and prostate cancer.

The results suggest that overall mortality was 15-30% lower among those with the highest fibre diets, compared to those with the lowest intakes.

Eating fibre-rich foods also reduced incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16-24%. For every 1,000 participants, the impact translated into 13 fewer deaths and six fewer cases of coronary heart disease.

The lowest daily intake of fibre was around 10g - similar to the Scottish average - while the most was around 40g. However, the authors concluded that consuming 25g to 29g each day would be "adequate".

Prof Cummings, who sits on the WHO committee which advises on nutrition guidelines, added: “This is an important paper because the changes are big. But it also suddenly brings together 50 years of work on dietary fibre - the time to do the research is over, let’s get on and implement the changes that are required.”

Heather Peace, Food Standard Scotland’s head of Public Health Nutrition, said the average Scottish diet fell "well below"goals on fibre intake.

She added: “This paper is a valuable addition to the evidence base which highlights the importance of fibre in the diet and its impact on our health. Fruits, vegetables, wholegrains, beans and pulses are all good sources of fibre.”