Total antioxidant capacity of the diet modulates the association between habitual nitrate intake and cardiovascular events: A longitudinal follow-up in Tehran Lipid and Glucose Study

Zahra Bahadoran; Mattias Carlström; Asghar Ghasemi; Parvin Mirmiran; Fereidoun Azizi; Farzad Hadaegh

doi:10.1186/s12986-018-0254-2

Total antioxidant capacity of the diet modulates the association between habitual nitrate intake and cardiovascular events: A longitudinal follow-up in Tehran Lipid and Glucose Study

Nutr Metab (Lond). 2018 Feb 27:15:19. doi: 10.1186/s12986-018-0254-2. eCollection 2018.

Authors

Zahra Bahadoran¹, Mattias Carlström², Asghar Ghasemi³, Parvin Mirmiran¹, Fereidoun Azizi⁴, Farzad Hadaegh⁵

Affiliations

¹ 1Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, No. 24, Sahid-Erabi St, Yemen St, Chamran Exp, Tehran, 19395-4763 Iran.
² 2Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
³ 3Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
⁴ 4Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
⁵ 5Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

Background: Considering the lack of data on the association between habitual dietary intakes of nitrate (NO₃^-) and nitrite (NO₂^-) and cardiovascular events, we assessed possible effects of dietary NO₃^- and NO₂^-, in the context of total antioxidant capacity (TAC) of the diet, with the risk of cardiovascular (CVD) outcomes.

Methods: Adult men and women without CVD (n = 2369) were recruited from the Tehran Lipid and Glucose Study and were followed for a mean of 6.7 years. Dietary NO₃^- and NO₂^- intakes, as well as dietary TAC and nitric oxide (NO) index were assessed at baseline (2006-2008). Multivariable-adjusted Cox proportional hazards regression models were used to estimate risk of CVD above and below median of dietary intakes of NO₃^-/NO₂^- and dietary TAC and NO index. Due to a significant interaction between NO₃^-/NO₂^- intake and TAC, stratified analyses were done for < and ≥ median dietary TAC.

Results: Daily mean (SD) dietary NO₃^- and NO₂^- intakes were 460 (195) and 9.5 (3.9) mg; mean (SD) dietary TAC and NO index was 1406 (740) and 338 (197) μmol trolox equivalent (TE)/100 g. In subjects with lower dietary TAC, higher intake of NO₃^- (≥ 430 mg/d) was accompanied with an increased risk of CVD (HR = 3.28, 95% CI = 1.54-6.99). There were no significant associations between dietary intakes of NO₂^-, TAC of the diet and NO index with the occurrence of CVD events during the study follow-up.

Conclusion: High habitual intake of NO₃^-, in the context of low TAC of the food, may be associated with the risk of CVD outcomes.

Keywords: Cardiovascular disease; Dietary nitrate and nitrite; Total antioxidant capacity.