A large (61,000 subject) observational study from Sweden published in British Medical Journal in 2018. (With the usual caveats about correlation not causation, non-randomization etc.).
Nut consumption ≥3 times/week was associated with an 18% reduced risk of atrial fibrillation.
Nuts are a great source of the following nutrients:
- unsaturated fatty acids
- protein
- fiber
- magnesium, potassium, zinc
- vitamin E, folic acid
- phenols, phytosterols.
Nut consumption may influence cardiovascular health by:
- improving blood lipid levels
- lower blood pressure
- improving endothelial function
- reducing the risk of weight gain
- via antioxidant and anti-inflammatory effects
Positive correlation was seen for 7 cardiovascular diseases, however strongest correlation was seen for atrial fibrillation.

Other studies have also observed association between nut intake and cardiovascular disease.



Excellent review article re. health benefits of nuts from the journal Nutrients by Emilio Ros. Full disclosure – Emilio Ros received research funding from the California Walnut Commission, Sameer Oza did NOT.
Another excellent review article from the American Journal of Clinical Nutrition.