Dietary fat and fatty foods in the prevention of non-communicable diseases: A review of the evidence.

Reducing the intake of total fat, saturated fatty acids (SFA) and dietary cholesterol was a cornerstone of dietary guidance in past decades. This emphasis shifted recently from lowering the intake of total fat to focusing on the quality of dietary fat intake, the avoidance of industrial trans -fatty acids (TFA), and the substitution of SFA with unsaturated fatty acids. There is also a trend towards investigating diet-disease associations of fatty foods rather than nutrients. We aimed to summarize comprehensively the currently available evidence for total dietary fat, fat quality, and fatty foods such as butter, vegetable oils, nuts and seeds on risk of non-communicable diseases including cardiovascular disease (and its risk factors), cancer, type 2 diabetes, and neurodegenerative diseases. The findings from systematic reviews of prospective observational studies, which often compared extreme intake categories, found mainly no association of total fat, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and SFA with risk of non-communicable diseases. Systematic reviews of randomized controlled trials indicate that SFA and/or TFA substitution with MUFA and/or PUFA improves blood lipids and markers of glycemic control (observed only for SFA replacement), with the effect of PUFA being more pronounced. A higher intake of total TFA was associated increased risk of cardiovascular disease. In line with current dietary guidelines, the available published evidence deems it reasonable to recommend replacement of SFA with MUFA and PUFA and avoidance of consumption of industrial TFA. • Reducing the intake of total fat, saturated fatty acids and dietary cholesterol was a cornerstone of dietary guidance in past decades. • Findings from systematic reviews of observational studies found mainly no association of total fat and fatty acids with risk of non-communicable diseases. • Systematic reviews of randomized trials indicate that saturated fatty acids and/or trans fatty acids substitution with monounsaturated fatty acids and/or polyunsaturated fatty acids improves blood lipids. • A higher intake of total trans -fatty acids was associated increased risk of cardiovascular disease. • The available evidence deems it reasonable to recommend replacement of saturated fatty acids with unsaturated fatty acids and avoidance of consumption of industrial trans -fat. [ABSTRACT FROM AUTHOR]