Use plant oils instead of lard or butter; rotating oils or buying flaxseed oil has no proven extra heart benefit
Replacing saturated fats such as lard and butter reduced cardiovascular events by about 17%, without a clear change in overall mortality. There is no evidence here that rotating soybean, corn and rapeseed oils changes outcomes. More flaxseed oil did not clearly reduce coronary disease.
What it takes
No extra spending; plant oil is already the main cooking fat in most households. Giving up a preference for lard in stir-fries or rice may take effort.
What you may gain
A Cochrane review of 15 randomized trials, 56,675 people, each lasting at least two years, found 17% fewer combined cardiovascular events after reducing saturated fat (RR 0.83, 0.70–0.98). All-cause mortality changed little (RR 0.96, 0.90–1.03), as did cardiovascular mortality (RR 0.95, 0.80–1.12). Replacement with polyunsaturated fat, prominent in soybean and corn oils, did not clearly differ from replacement with carbohydrate. Data for monounsaturated fat, prominent in rapeseed and olive oils, were insufficient. Another Cochrane review of 19 trials and 6,461 people found no clear benefit or harm from increased omega-6 linoleic acid: RR 1.00 for all-cause mortality (0.88–1.12) and 0.97 for cardiovascular events (0.81–1.15). A third review, 86 trials and 162,796 people overall, found little effect from increased plant omega-3, prominent in flaxseed and perilla oils: RR 1.01 for all-cause mortality (0.84–1.20) and 1.00 for coronary events (0.82–1.22).
Context & considerations
Some argue that omega-6 in soybean and corn oils promotes inflammation and should be reduced or replaced. The randomized omega-6 trials above found no clear harm, though the authors rated certainty low. Benefit is rated medium based on 17% fewer cardiovascular events, with no mortality change. Limit total oil whichever type you use: China's dietary guidelines recommend 25–30 g of cooking oil per person daily.
Research & references
Hooper L, Martin N, Jimoh OF, et al. (2020). Reduction in saturated fat for cardiovascular disease. Cochrane Database of Systematic Reviews, (5), CD011737. https://doi.org/10.1002/14651858.CD011737.pub3 ; Hooper L, Al-Khudairy L, Abdelhamid AS, et al. (2018). Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, (11), CD011094. https://doi.org/10.1002/14651858.CD011094.pub4 ; Abdelhamid AS, Brown TJ, Brainard JS, et al. (2020). Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, (3), CD003177. https://doi.org/10.1002/14651858.CD003177.pub5 ; Chinese Nutrition Society (2022). Dietary Guidelines for Chinese Residents, 2022. People's Medical Publishing House.