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Genetic study finds no clear heart benefit from vegetables

Genetically Predicted Vegetable Intake and Cardiovascular Diseases and Risk Factors: An Investigation with Mendelian Randomization.

Overview

Feng Q et al.. Nutrients 2023 · PMID 37686714 · DOI 10.3390/nu15173682

Gene-based estimates of vegetable intake were not linked to heart disease, with a weak signal for less stroke.

Does the study support the specific claim? Partly · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Test causality of vegetable intake for CVD with genetics.
How was the study done?: Mendelian randomization.
How many people, animals or samples were studied?: 1.2 million.
What was actually found?: Null for CHD, HF, AF; nominal stroke reduction.
How large was the observed effect?: Stroke OR 0.82 (0.69-0.98).
What do the results mean in everyday life?: Uncertainty about how much vegetables protect the heart.
What are the study's limitations?: Weak instruments.
What does it say about Elawady's specific claim?: Does not support eliminating vegetables; adds uncertainty.
Do the results apply to Germany and Europe?: European.
What can explicitly not be concluded from this study?: Cannot evaluate nutrient deficiency.

Authors: Feng Q et al.
Journal: Nutrients
Year: 2023
Identifier: PMID 37686714 DOI 10.3390/nu15173682
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 no conflict of interest. | Funding (PubMed grant list): Medical Research Council; Wellcome Trust

Is genetically predicted vegetable intake associated with cardiovascular outcomes and risk factors?

Study design: Other – One- and two-sample Mendelian randomization with meta-analysis (genetic instruments for cooked and raw vegetable intake)
Population: UK Biobank and GWAS consortia
Country: Mainly European ancestry populations
Period: not applicable
Sample size: 1.2 million participants (MR meta-analysis)
Inclusion and exclusion criteria: not stated in abstract

Exposure / intervention: Genetically predicted cooked (15 variants) and raw (28 variants) vegetable intake
Comparator: Per daily serving
Endpoints: CHD, stroke, heart failure, atrial fibrillation; lipids, BP, BMI, glycaemic traits
Statistical methods: Multivariable MR; Bonferroni correction

Results: Null associations for CHD, heart failure and AF; raw vegetables nominally associated with stroke (OR 0.82, 0.69-0.98 per daily serving, p = 0.03, not significant after correction); null for lipids, BP, BMI, glycaemic traits.
Absolute risks: not reported
Authors' conclusion: Null evidence for genetically predicted vegetable intake with CHD, AF, HF or risk factors; raw vegetables may reduce stroke risk; true associations cannot be ruled out.

Orienting tool: none applicable
Type of assessment: simplified assessment (abstract only)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: MR assumptions (relevance, independence, exclusion restriction) questionable for dietary behaviours.

Stroke OR CI log-symmetric; p 0.03 does not survive multiplicity correction (stats/C-VEG-16_mortality.py).

Mixed: adds uncertainty about the causal CVD benefit of vegetables; irrelevant to nutrient adequacy.

Cohort meta-analyses; fibre and potassium RCTs.

European ancestry; applicable.

Supports moderate rather than high certainty for a causal vegetable-CVD effect.

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

Better genetic instruments.