A series of systematic reviews and meta-analyses of prospective studies and randomized controlled trials with relatively high intakes of dietary fiber and whole grains revealed complementary findings, and striking dose-response evidence indicates that the relationships to several non-communicable diseases could be causal. The analyses included about 135 million person-years of data from 185 prospective studies and 58 clinical trials with 4635 adult participants. Observational data suggest a 15–30% decrease in all-cause and cardiovascular mortality, and incidence of coronary heart disease, stroke incidence and mortality, type 2 diabetes, and colorectal cancer when comparing the highest dietary fiber consumers with the lowest consumers. Clinical trials show significantly lower bodyweight, systolic blood pressure, and total cholesterol when comparing higher with lower intakes of dietary fiber. Risk reduction associated with a range of critical outcomes was greatest when daily intake of dietary fiber was between 25 g and 29 g. Dose-response curves suggested that higher intakes of dietary fiber could confer even greater benefit to protect against cardiovascular diseases, type 2 diabetes, and colorectal and breast cancer. Similar findings for whole grain intake were observed. Smaller or no risk reductions were found with the observational data when comparing the effects of diets characterized by low rather than higher glycemic index or load. Most people worldwide currently consume less than 20 g of dietary fiber per day. Source: https://www.thelancet.com/
