Author Identifier (ORCID)
Catherine P. Bondonno: https://orcid.org/0000-0001-8509-439X
Jonathan M. Hodgson: https://orcid.org/0000-0001-6184-7764
Abstract
BackgroundInorganic nitrate from dietary sources has raised health concerns due to its possible conversion into carcinogenic N-nitrosamines, leading to strict regulations on nitrate concentrations in food and drinking water.ObjectivesIn this study, which was a part of a larger randomized controlled trial, we evaluated urinary excretion of N-nitrosamines in response to daily dietary nitrate intake over a 5-wk period using 2 different forms of nitrate administration.MethodsA total of 231 participants with mild hypertension were randomly assigned into 3 groups. Group 1 (n = 78) consumed vegetables low in nitrate along with a placebo capsule (300 mg potassium chloride). Group 2 (n = 77) consumed the same low-nitrate vegetables plus a potassium nitrate supplement (300 mg). Group 3 (n = 77) consumed nitrate-rich leafy green vegetables providing 300 mg nitrate daily plus the placebo capsule. Twenty-four-hour urine samples were collected before and after the intervention. Nitrate was measured with high-pressure liquid chromatography and N-nitrosamine concentrations were quantified using ultra high-pressure liquid chromatography-tandem mass spectrometry. A paired t-test was used for statistical analyses.ResultsAs expected, urinary nitrate increased ∼5- to 6-fold in participants consuming nitrate-rich vegetables or potassium nitrate compared with those consuming potassium chloride. Total urinary excretion of N-nitrosamines was low across all groups under basal conditions (<5 μg/24 h) and did not significantly change after the intervention. A similar lack of change was observed for each of the 7 individual N-nitrosamine species measured.ConclusionsThese findings suggest that a 5-wk dietary intake of nitrate mostly exceeding the current consensus for upper limit of the acceptable daily intake (3.7 mg/kg/d), whether provided as a vegetable source or as a nitrate salt, does not increase urinary excretion of N-nitrosamines.This study was registered at clinicaltrials.gov as NCT02916615.
Keywords
Cancer, diet, N-nitrosamines, nitrate, nitric oxide, nitrite, vitamin C
Document Type
Journal Article
Date of Publication
5-1-2026
Volume
123
Issue
5
PubMed ID
41724486
Publication Title
The American Journal of Clinical Nutrition
Publisher
Elsevier
School
Nutrition and Health Innovation Research Institute / School of Medical and Health Sciences
Funders
Jochnick Foundation / Swedish Research Council / Knut and Alice Wallenberg Foundation / Swedish Heart and Lung Foundation / Axfood / Karolinska Institutet / National Health and Medical Research Council / Western Australian Future Health Research and Innovation Fund
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
Bondonno, C. P., Sundqvist, M. L., Shinde, S., Croft, K., Hodgson, J. M., Carlström, M., Weitzberg, E., & Lundberg, J. O. (2026). A clinical study examining the effects of dietary nitrate on urinary N-nitrosamines. The American Journal of Clinical Nutrition, 123(5), 101239. https://doi.org/10.1016/j.ajcnut.2026.101239