31 Oct Higher Intake of Linoleic Acid Leads To Lower Coronary Heart Disease Risk
Medical Research: What is the background for this study? What are the main findings?
Dr. Hu: There has been much confusion and sensational headlines about the role of different types of fat in coronary heart disease. A recent meta-analysis suggested that higher saturated fat intake was not associated with coronary heart disease (CHD), but people don’t consume saturated fat in isolation from other components of diet. Typically people swap for one type of fat for another. Therefore it is important to look at replacement nutrient when we talk about health effects of saturated fat. Randomized clinical trials have shown that replacing saturated fat with polyunsaturated fat reduces total and LDL cholesterol. Thus it is important to examine whether such replacement confers long-term beneficial effects on heart disease prevention. We performed a systematic review and meta-analysis of prospective cohort studies to summarize the evidence regarding the link between dietary intake of linoleic acid (the predominant type of polyunsaturated fat) and heart disease risk in generally healthy people. We identified 13 published and unpublished cohort studies with a total of 310,602 individuals and 12,479 total coronary heart disease events including 5,882 CHD deaths. We found that dietary linoleic acid intake is inversely associated with coronary heart disease risk in a dose-response manner—meaning, higher intake of linoleic acid resulted in a lower risk of CHD. Comparing the highest to the lowest level of consumption, dietary linoleic acid was associated with a 15% lower risk of coronary heart disease events and a 21% lower risk of CHD deaths. These results were independent of common coronary heart disease risk factors such as smoking and other dietary factors such as fiber consumption.
Medical Research: What should clinicians and patients take away from your report?
Dr. Hu: The main conclusion of our study is that people who swap 5% of the calories they consume from saturated fat sources such as red meat and butter with foods containing linoleic acid—the main polyunsaturated fat found in vegetable oil, nuts, and seeds—lowered their risk of coronary heart disease (CHD) events by 9% and their risk of death from CHD by 13%. In practice, it is desirable to replace butter, lard, and fat from red meat with liquid plant oils in cooking and at the table. Trans fat from partially hydrogenated vegetable oils should be avoided,
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Hu: Future studies should examine the effects of replacing saturated fat with monounsaturated fat from olive oil, nuts, and other plant sources on coronary heart disease risk. Clinical trials have shown that substituting monounsaturated fat for saturated fat is beneficial for blood lipids, but its relationship with coronary heart disease risk is less clear compared to that for polyunsaturated fat.
Dietary Linoleic Acid and Risk of Coronary Heart Disease: A Systematic Review and Meta-Analysis of Prospective Cohort Studies
S. Farvid, M. Ding, A. Pan, Q. Sun, S. E. Chiuve, L. M. Steffen, W. C. Willett, F. B. Hu. Circulation, 2014; 130 (18): 1568 DOI: 10.1161/CIRCULATIONAHA.114.010236