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Nitrate from vegetables linked to less heart disease

Vegetable nitrate intake, blood pressure and incident cardiovascular disease: Danish Diet, Cancer, and Health Study.

Overview

Bondonno CP et al.. Eur J Epidemiol 2021 · PMID 33884541 · DOI 10.1007/s10654-021-00747-3

Danes eating about a cup of leafy greens' worth of nitrate daily had 15% less cardiovascular disease than those eating the least.

Does the study support the specific claim? No · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Relate vegetable nitrate to BP and CVD.
How was the study done?: Cohort, 23 years.
How many people, animals or samples were studied?: 53,150 adults.
What was actually found?: Lower BP and CVD with moderate intake.
How large was the observed effect?: HR 0.85 (0.82-0.89).
What do the results mean in everyday life?: Nitrate from greens does not appear harmful for adults; it may be protective.
What are the study's limitations?: Observational.
What does it say about Elawady's specific claim?: Contradicts the claim.
Do the results apply to Germany and Europe?: European.
What can explicitly not be concluded from this study?: Cannot prove causation.

Authors: Bondonno CP et al.
Journal: Eur J Epidemiol
Year: 2021
Identifier: PMID 33884541 DOI 10.1007/s10654-021-00747-3
Verification: verified – PubMed efetch 2026-10-26; Crossref 2026-10-26
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: COI statement: The authors declare that they have no conflict of interest. | Funding (PubMed grant list): Healy Medical Research Foundation; National Health and Medical Research Council; National Health and Medical Research Council e Médicale (FR); National Health and Medical Research Council he Médicale (FR); National Heart Foundation of Australia; The Danish Heart Foundation; Wellcome Trust

Is habitual vegetable nitrate intake associated with blood pressure and incident CVD?

Study design: Cohort study – Prospective cohort (Danish Diet, Cancer and Health), 23 years follow-up
Population: Danish adults without baseline CVD
Country: Denmark
Period: Baseline 1993-1997; 23 years follow-up
Sample size: 53,150 (14,088 CVD cases)
Inclusion and exclusion criteria: not stated in abstract

Exposure / intervention: Vegetable nitrate (comprehensive database)
Comparator: Lowest quintile (median 23 mg/day)
Endpoints: Baseline BP; incident CVD and subtypes
Statistical methods: Restricted cubic splines in Cox models; mediation by SBP

Results: Highest quintile (median 141 mg/day): SBP -2.58 mmHg (-3.12 to -2.05), DBP -1.38 mmHg. Moderate intake (median 59 mg/day) vs lowest: CVD HR 0.85 (0.82-0.89); 12-26% lower ischaemic heart disease, heart failure, ischaemic stroke and PAD hospitalisations; plateau at ~60 mg/day; 21.9% mediated by SBP.
Absolute risks: not reported
Authors' conclusion: Consumption of at least ~60 mg/day of vegetable nitrate (~1 cup of green leafy vegetables) may mitigate CVD risk.

HR CI log-symmetric within rounding (stats/C-VEG-08_nitrate.py).

Directly contradicts the idea that vegetable nitrate harms adults.

Ward 2010 thyroid cancer signal (imprecise).

European cohort.

Consistent with BP-lowering RCTs (Siervo 2013).

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	high
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

Separation from total vegetable effects.