karppaus.infon arkistoitu foorumi

Published: 30 September 2023
Saturated fat, the estimated absolute risk and certainty of risk for mortality and major cancer and cardiometabolic outcomes: an overview of systematic reviews

Abstract
Objective
To assess the impact of reducing saturated fat or fatty foods, or replacing saturated fat with unsaturated fat, carbohydrate or protein, on the risk of mortality and major cancer and cardiometabolic outcomes in adults.

Methods
We searched MEDLINE, EMBASE, CINAHL, and references of included studies for systematic reviews and meta-analyses (SRMAs) of randomized controlled trials (RCTs) and observational studies in adults published in the past 10 years. Eligible reviews investigated reducing saturated fat or fatty foods or replacing saturated fat with unsaturated fat, carbohydrate or protein, on the risk of cancer and cardiometabolic outcomes and assessed the certainty of evidence for each outcome using, for example, the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) approach. We assessed the quality of SRMAs using a modified version of AMSTAR-2. Results were summarized as absolute estimates of effect together with the certainty of effects using a narrative synthesis approach.

Results
We included 17 SRMAs (13 reviews of observational studies with follow-up 1 to 34 years; 4 reviews of RCTs with follow-up 1 to 17 years). The quality of two-thirds of the SRMAs was critically low to moderate; the main limitations included deficient reporting of study selection, absolute effect estimates, sources of funding, and a priori subgroups to explore heterogeneity. Our included reviews reported > 100 estimates of effect across 11 critically important cancer and cardiometabolic outcomes. High quality SRMAs consistently and predominantly reported low to very low certainty evidence that reducing or replacing saturated fat was associated with a very small risk reduction in cancer and cardiometabolic endpoints. The risk reductions where approximately divided, some being statistically significant and some being not statistically significant. However, based on 2 moderate to high quality reviews, we found moderate certainty evidence for a small but important effect that was statistically significant for two outcomes (total mortality events [20 fewer events per 1000 followed] and combined cardiovascular events [16 fewer per 1000 followed]). Conversely, 4 moderate to high quality reviews showed very small effects on total mortality, with 3 of these reviews showing non-statistically significant mortality effects.

Conclusion
Systematic reviews investigating the impact of SFA on mortality and major cancer and cardiometabolic outcomes almost universally suggest very small absolute changes in risk, and the data is based primarily on low and very low certainty evidence.

New systematic review on sat fats and mortality, major cancer, major cardiometabolic outcomes.
"Almost universally suggest v. small absolute changes in risk, and the data is based primarily on low and very low certainty evidence"
i.e.: SATURATED FATS DON'T CAUSE heart disease, cancer, diabetes, death.
There are now nearly 30 such reviews concluding virtually the same. YET...

Nearly all public health authorities refuse to drop their caps on saturated fats. The American Heart Association, the US Dietary Guidelines, the World Health Organization. They are all ignoring the science.

Why? Cognitive dissonance, maybe. Or maybe trying to protect the massive fake-food 'plant-based' industries that depend on limiting meat/dairy via caps on sat fats. Or similar motive from climate-change activists. I can think of others..