Professor Mann said the health benefits of dietary fibre - contained in foods such as whole grains, pulses, vegetables and fruit - come from its chemistry, physical properties, physiology and its effects on metabolism. "For every 8 gram increase of dietary fiber eaten a day, total deaths and incidences of coronary heart disease, type 2 diabetes and colorectal cancer decreased by 5 to 27 percent".
While the consumption of 25-29g of fibre per day was adequate, the findings suggest that a higher daily intake could offer even greater protection.
The researchers focused on the effects of dietary fibre and whole grains on the risk of premature deaths from and rates of coronary heart disease, cardiovascular disease and stroke, as well as rates of type 2 diabetes, colorectal cancer and cancers associated with obesity: breast, endometrial, oesophageal and prostate cancer. The latest research is the most definitive evidence of the health benefits of a high fiber intake.
Most people worldwide consume less than 20g of dietary fibre per day. But it adds that for people with an iron deficiency, high levels of whole grains can further reduce iron levels.
Soluble fibre helps to reduce cholesterol and manage blood sugar levels.
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.
Glycemic index is not as good as dietary fiber when considering whether something is a good carbohydrate-containing food, Mann said. What are some rich sources of fiber that people can integrate into their daily diets? Not many, however, know that pop corn is also a possible source of fiber, with 14.5 grams of fiber for every 100 grams of popped popcorn.
Whole grains are also important in fiber content and important to the diet.
Helen Stokes-Lampard, chair of the Royal College of General Practitioners, wrote in an email that "living a healthy lifestyle is an obvious route to improving our health outcomes, and eating a balanced diet, as well as taking regular exercise, getting enough sleep, drinking alcohol in moderation and not smoking, is a key part of this".
Written by Nina Avramova for CNN.