Research

Mixed

Higher circulating levels of long-chain monounsaturated fatty acids (specifically 22:1 and 24:1) are associated with a significantly higher incidence of congestive heart failure in humans.

Focus on the specific type of fat rather than just the category. While common monounsaturated fats (like olive oil) are generally good, high levels of long-chain monounsaturated fats (specifically erucic acid 22:1 and nervonic acid 24:1) found in certain fish, mustard, and meats are linked to a higher risk of heart failure. If you have risk factors for heart failure, consider moderating intake of foods high in these specific long-chain fatty acids.

GoodSupportsHIGH confidence
In multivariable-adjusted analyses, higher levels of both 22:1 and 24:1, but not 20:1, were significantly associated with higher CHF incidence... higher circulating levels of 22:1 and 24:1... were associated with incident congestive heart failure in 2 independent cohorts, suggesting possible cardiotoxicity of LCMUFAs in humans.
Fumiaki Imamura et al. · Circulation · 2013

Why this rating

Two large, independent prospective cohorts with objective biomarkers (plasma phospholipids) and rigorous adjustment for confounders, though observational design prevents causal proof.

Source

Long-Chain Monounsaturated Fatty Acids and Incidence of Congestive Heart Failure in 2 Prospective Cohorts

Fumiaki Imamura et al. · Circulation · 2013

DOI 10.1161/circulationaha.112.001197

cohort · n=7271Cited 79×
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DOI resolved against Crossref · corpus check 2026-06-10

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