Higher dietary fibre intake lowers risks of CVD, stroke mortality

Individuals who consume a high amount of dietary fibre (DF) tend to live longer, suggests a Japan study, which reveals the association of higher DF intake with a lower risk of cardiovascular disease (CVD) mortality in men and a reduced risk of stroke mortality in women.

On the other hand, intake of carbohydrate, available carbohydrate and starch is not associated with the risk of CVD mortality in men or women.

“In this … study of a Japanese population, we found that higher DF intake had a protective effect against CVD mortality in men and against stroke mortality in women,” the researchers said.

A total of 823 deaths occurred during 24 years of follow-up. In multivariable-adjusted models, men in the highest quartile of DF intake had a lower risk of CVD mortality (hazard ratio [HR], 0.64, 95 percent confidence interval [CI], 0.47–0.87; p_trend=0.007) compared with those in the lowest quartile. Such association was not significant in women. [Eur J Clin Nutr 2020;74:67-76]

Furthermore, multivariable-adjusted models showed a lower risk of total stroke mortality among women in the highest quartile of DF intake (HR, 0.61, 95 percent CI, 0.38–0.98; p_trend=0.046) compared with those in the lowest quartile.

The association between higher DF intake and a reduced risk of CVD was also reported in several studies in the past. In addition to this, two other Japan studies have found an association between DF intake and a lower CVD mortality risk. [Arch Intern Med 2004;164:370-376; Brit Med J 2013;347:f6879; Stroke 2013;44:1360-1368; J Nutr 2010;140:1445-1453; Eur J Clin Nutr 2011;65:1233-1241]

One possible reason for the varied results between men and women was lifestyle differences, with the prevalence of current smoking and alcohol consumption being higher in men than in women, according to the researchers. This could also be partially explained by the fact that CVD events were fewer in women than in men.

Kokubo and colleagues have also previously reported on the difference of the effect of DF intake between men and women. [Eur J Clin Nutr 2011;65:1233-1241]

On the other hand, consumption of carbohydrate, available carbohydrate and starch did not show a significant association with CVD mortality.

“One reason we did not find an association between carbohydrate intake and a risk of CVD mortality … might have been that we did not consider intake of protein or fat,” the researchers said.

“Only one previous study in a Japanese population has reported on the relation between carbohydrate intake and stroke mortality, and it found no significant association. The results of our study supported this conclusion,” they added. [Metabolism 2010;59:1574-1582]

The current study prospectively followed 3,916 men and 5,009 women (aged 30–79 years) without CVD at baseline who participated in the National Nutrition Survey in Japan. The researchers used Cox proportional hazards models to estimate HRs and their 95 percent CIs for CVD mortality by quartiles of exposure variables.