New research commissioned by the World Health Organization has found that including plenty of fiber and whole grains in the diet can help reduce the risk of chronic diseases such as coronary heart disease, stroke, type 2 diabetes and colorectal cancer.
Carried out by researchers at the University of Otago, New Zealand and the University of Dundee, Scotland, the new meta-analysis looked at 185 observational studies containing data that relate to 135 million person years -- which takes into account the number of people in the study and the amount of time each person spends in the study -- and 58 clinical trials involving 4,635 healthy adult participants.
The researchers focused on the effects of dietary fiber 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 findings, published in The Lancet, suggested that those who ate the highest amount of fiber, with a daily intake of between 25g and 29g, benefited from a 15 to 30 percent decrease in all-cause and cardiovascular related mortality when compared to people who ate the least amount of fiber.
In addition, eating fiber-rich foods also reduced the rates of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16 to 24 percent.
Moreover, there also appeared to be a dose-response relationship, suggesting that a higher intake of dietary fiber above 25g to 29g per day could bring even greater benefits to protect against cardiovascular diseases, type 2 diabetes, and colorectal and breast cancer.
Increasing fiber intake was also associated with lower body weight and cholesterol, compared with lower intakes.
Higher intakes of whole grains were also associated with a 13 to 33 percent reduction in the risk of developing chronic diseases, and for every 15g increase of whole grains eaten per day, total deaths and rates of coronary heart disease, type 2 diabetes and colorectal cancer decreased by 2 to 19 percent.
Whole grains were also associated with a reduction in body weight, with the researchers explaining that whole grains are high in dietary fiber, which could explain their beneficial effects.
However, the study found only limited support that diets with a low glycemic index and low glycemic load offered protection against type 2 diabetes and stroke. They explained that foods with a low glycemic index or low glycemic load may also contain added sugars, saturated fats, and sodium which could account for the health benefits of this type of diet being less clear.
Most people worldwide consume less than 20 g of dietary fibre per day. Rich sources of dietary fibre include whole grains, pulses, vegetables and fruit.