Reducing saturated fat, increasing polyunsaturated fat ‘cuts CHD risk’
MedWire News: Increasing consumption of polyunsaturated fatty acids (PUFAs) in place of saturated fatty acids (SFAs) is associated with a reduction in coronary heart disease (CHD) events, a review of randomized controlled trials suggests.
The authors say that their results support public health recommendations to substitute dietary SFAs with PUFAs in order to reduce the burden of heart disease.
Dariush Mozaffarian (Harvard Medical School, Boston, Massachusetts, USA) and team undertook a systematic review and meta-analysis with the aim of determining the impact of substituting SFAs for PUFAs on CHD outcomes.
This issue is “surprisingly understudied,” they remark, especially given the contradictory dietary recommendations regarding the consumption of PUFAs.
The team searched literature databases for randomized controlled trials in which adult participants increased their consumption of total or n-6 PUFAs for at least 1 year, in the absence of any other major intervention, and reported “hard” CHD events (ie, myocardial infarction, CHD death, or sudden death) as study endpoints.
The final meta-analysis included eight trials, totaling 13,614 participants with 1042 CHD events.
The average weighted PUFA consumption was 14.9% of energy in intervention groups and 5.0% in control groups. The overall pooled risk reduction for CHD events was 19% (relative risk 0.81) for intervention versus control, which corresponded to a 10% reduction in CHD risk for each 5% energy increase in PUFA.
Further analyses found no evidence of statistical heterogeneity, and meta-regression suggested that study duration was an independent determinant of risk reduction, with studies of longer duration showing greater benefits than shorter studies.
Mozaffarian’s group says that the study was unable to distinguish the benefits of reducing SFAs from those of increasing PUFAs. Nevertheless, they advise: “Instead of trying to lower PUFA consumption, a shift toward greater population PUFA consumption in place of SFA could significantly reduce rate of CHD.”
The study, which appears in the open-access journal PLoS Medicine, is accompanied by an Editors’ Summary that concluded: “In the light of these findings, future recommendations to reduce SFA in the diet should stress the importance of replacing SFA with PUFA rather than with other forms of energy.”
Importantly, the journal Editors added: “The current advice to limit PUFA intake should be revised.”
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By Joanna Lyford