Observational studies and clinical trials conducted over nearly 40 years reveal the health benefits of eating at least 25g or more of dietary fibre a day, according to research commissioned by the World Health Organization.
People who had higher intakes of dietary fibre and whole grains had lower rates of chronic diseases, such as heart disease, cancer and diabetes, compared to those with diets low in fibre and whole grains.
Current UK guidelines recommend that people eat 30g a day, yet only 9 per cent of British adults meet the target. Fibre consumption is even worse in the US, with the average adult eating just 15g of fibre a day.
Higher fibre diets were associated with a 15 to 31 percent reduction in the risk of death and disease. That meant 13 fewer deaths and six fewer cases of coronary heart disease, per 1,000 participants in the studies.
People with diets high in whole grains saw similar benefits, with up to 33 percent reduction in risk, translating to 26 fewer deaths and seven fewer cases of coronary heart disease.
The study, published in The Lancet, one of the most prestigious and oldest medical journals, suggests eating at least 25 to 29 grams of dietary fibre per day to achieve these health benefits. Higher intakes could produce more benefits; however, the authors note that consuming copious amounts of it could have ill-effects for people with low iron or mineral levels.
The research consisted of analysing 185 observational studies and 58 clinical trials that were conducted over nearly 40 years.
This landmark study is important and timely because the Internet is a wasteland of deranged dietary advice. Quack ‘doctors’, self-proclaimed nutritionists, and – excuse my French – broscience baloney have infiltrated forums, social media and YouTube. In particular, there is a growing trend advocating the carnivore diet. This consists of consuming only animal foods. No fruits. No vegetables. But all the burgers, steaks and pork chops you want, which are often eaten raw by enthusiasts.
This dangerous and stupid dietary advice is gaining popularity, despite it being diametrically opposed to the robust, high quality empirical evidence that continues to emerge in the scientific literature.
For instance, another recent study, also published in The Lancet, showed that Tsimane people (forager-horticulturalist population of the Bolivian Amazon) have the lowest reported levels of vascular ageing of all populations yet studied. It turns out that their diet is largely carbohydrate-based (72%) and includes high fibre foods such as rice, plantain, corn, nuts and fruits. Protein constitutes only 14% of their diet, and they consume very low levels of fat. So much for the carnivore diet.
In summary, recent studies confirm that fibre and whole grain intakes are vitally important for longer term health. If your current diet is low in fibre, increase it gradually to help avoid bowel upset.