Habitual dietary intake of flavonoids and all-cause and cause-specific mortality: Golestan cohort study

Jalal Hejazi,Abdolsamad Gharavi,Azita Hekmatdoost,Christian C Abnet,Ehsan Hejazi,Akram Pourshams,Sadaf G Sepanlou,Paul Brennan,Arash Etemadi,Farin Kamangar,Reza Malekzadeh,Hossein Poustchi,Paolo Boffetta,Masoud Sotoudeh,Matin Ghanavati,Akbar Fazeltabarmalekshah,Masoud Khoshnia,Sanford M Dawsey,Amir Ali Sohrabpour

doi:10.1186/s12937-020-00627-8

Abstract

Background and objectivesFlavonoids are the most important group of polyphenols with well-known beneficial effects on health. However; the association of intake of total flavonoid or their subclasses with all-cause or cause-specific mortality is not fully understood. The present study aims to evaluate the association between intake of total flavonoid, flavonoid subclasses, and total and cause-specific mortality in a developing country.MethodsA total number of 49,173 participants from the Golestan cohort study, who completed a validated food frequency questionnaire at recruitment, were followed from 2004 till 2018. Phenol-Explorer database was applied to estimate dietary intakes of total flavonoid and different flavonoid subclasses. Associations were examined using adjusted Cox proportional hazards models.ResultsDuring a mean follow-up of 10.63 years, 5104 deaths were reported. After adjusting for several potential confounders, the hazard ratios (HRs) of all-cause mortality for the highest versus the lowest quintile of dietary flavanones, flavones, isoflavonoids, and dihydrochalcones were 0.81 (95% confidence interval = 0.73–0.89), 0.83(0.76–0.92), 0.88(0.80–0.96) and 0.83(0.77–0.90), respectively. However, there was no association between total flavonoid intake or other flavonoid subclasses with all-cause mortality. In cause-specific mortality analyses, flavanones and flavones intakes were inversely associated with CVD mortality [HRs: 0.86(0.73–1.00) and 0.85(0.72–1.00)] and isoflavonoids and dihydrochalcones were the only flavonoid subclasses that showed a protective association against cancer mortality [HR: 0.82(0.68–0.98)].ConclusionThe results of our study suggest that certain subclasses of flavonoids can reduce all-cause mortality and mortality rate from CVD and cancer.

Highlights

Flavonoids, an important subgroup of polyphenols, have a substantial impact on different aspects of health
The conduct of Golestan cohort study (GCS) was approved by the institutional review boards of the Digestive Disease Research Center of Tehran University of Medical Sciences, the US National Cancer Institute (NCI), and the World Health Organization International Agency for Research on Cancer (IARC)
There were no marked differences in rates of all-cause mortality, cardiovascular mortality, or cancer mortality by quantiles of total flavonoid intake

Summary

Introduction

Flavonoids, an important subgroup of polyphenols, have a substantial impact on different aspects of health. Dietary flavonoids are chemically diverse and are divided into 6 main subclasses, i.e. flavanols or flavan-3ols (e.g. catechin, epicatechin, epigallocatechin), anthocyanins (e.g. cyanidin, pelargonidin, delphinidin, peonidin), flavanones (e.g. hesperetin, naringenin), flavonols (e.g. quercetin, kaempferol, myricetin), flavones (e.g. apigenin, luteolin), isoflavones (e.g. daidzein, genistein) and some subsidiary classes such as dihydrochalcones and chalcones (e.g. phloridzin, arbutin, phloretin, and chalconaringenin) [6]. These subclasses vary in their biological efficacy and bioavailability. The present study aims to evaluate the association between intake of total flavonoid, flavonoid subclasses, and total and cause-specific mortality in a developing country

Methods

Results

Discussion

Conclusion