【Introduction】
High-fiber diets reduce early mortality and reduce the incidence of and risk factors for various noncommunicable diseases. Therefore, we conducted a systematic review and meta-analysis of reports examining the association between dietary fiber intake and risk factors for mortality and cardiometabolic diseases in adults with prediabetes and diabetes (type 1 and type 2).
【Materials and Methods】
OVID Medline, Embase, PubMed, and the Cochrane Central Register of Controlled Trials were searched until January 18, 2019. We selected prospective cohort studies on dietary fiber intake and mortality, and controlled trials (parallel or crossover) of 6 weeks or longer that examined the effects of increased intake of whole grains and dietary fiber on glycemic control and cardiovascular disease risk factors.
【Results】
Two prospective cohort studies and 42 controlled trials were included in the analysis. The prospective cohort studies followed 8300 diabetic patients in 22 countries for a median of 8.8 years, and the comparative studies included data from 1789 patients.
The highest dietary fiber intake group had 45% lower risk of all-cause mortality and 39% lower risk of cardiovascular disease-related mortality than the lowest group were estimated from two prospective cohort studies. The risk of all-cause mortality was 35% (95% confidence interval, 10-48%) lower with 35 grams of fiber per day than 19 grams per day, and in absolute terms, there were 14 fewer deaths per 1,000 persons during the follow-up period.
In a controlled trial, increased dietary fiber intake was associated with significant improvements in HbA1c, fasting glucose, total cholesterol, LDL-cholesterol, triglyceride levels, body weight, waist circumference, and CRP.
【Discussion and Conclusion】
In many relatively wealthy countries, most adults consume about 20 g of dietary fiber per day*1. Increasing intake by 15 g per day to 35 g per day could be a reasonable goal to reduce the risk of early death by 10% to 48%.
Analyses of controlled trials have consistently shown improvements in various diabetes-related biochemical measures with increased fiber intake. This result support the findings of reduced risk of death in prospective cohort studies.
This result suggested that may apply to any type of diabetes, whether diet alone, oral medication, insulin, or a combination of the two, as well as to prediabetics.
One practical way to increase dietary fiber intake is to replace refined grains with whole grains.
【Research institution】
University of Otago (New Zealand)
*1 Nutr Res Rev 30, 2, 149-90, 2017
Dietary fibre and whole grains in diabetes management: Systematic review and meta-analyses
PLoS Med 17, 3, e1003053, 2020
