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What's an industrial fat
The PREDIMED trial was not terminated for harm. It was stopped early for benefit.
The trial enrolled 7,447 older adults at high cardiovascular risk and randomly assigned them to a Mediterranean diet with extra-virgin olive oil, a Mediterranean diet with nuts, or a low-fat control diet [5]. The planned follow-up was longer, but an independent data and safety monitoring board stopped the trial after a median of 4.8 years because the Mediterranean diet groups showed a clear reduction in major cardiovascular events [5]. The hazard ratio was 0.69 for the olive oil group and 0.72 for the nut group compared to the control [5]. The trial was not cut short because of safety concerns. It was cut short because the benefit was large enough that continuing to deny the intervention to the control group was considered unethical.
The interruption was not a termination. It was an early stop for efficacy, a standard practice in trials where the treatment effect crosses a pre-specified boundary. The PREDIMED findings have been widely replicated in observational studies and meta-analyses, consistently showing that higher adherence to a Mediterranean diet reduces all-cause and cardiovascular mortality [1][2][3][6][7]. The Lyon Diet Heart Study, a randomized secondary prevention trial, also stopped early after showing a 50–70% reduction in cardiovascular recurrence [4].
My call: the PREDIMED trial was interrupted because the diet worked, not because it failed. Confidence: high.
Sources used 7
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Mediterranean Diet in Older Adults: Cardiovascular Outcomes and Mortality from Observational and Interventional Studies—A Systematic Review and Meta-Analysis
This systematic review and meta-analysis assess the effectiveness of high adherence to the Mediterranean Diet in reducing all-cause mortality and cardiovascular outcomes among older adults, finding significant reductions in mortality and cardiovascular events associated with the…
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Mediterranean Diet and Mortality in People with Cardiovascular Disease: A Meta-Analysis of Prospective Cohort Studies
Greater adherence to the Mediterranean diet is linked to lower all-cause mortality in individuals with a history of cardiovascular disease, particularly in Mediterranean regions, while cardiovascular mortality shows a border-line reduction and results are limited by observationa…
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Dietary inflammatory index or Mediterranean diet score as risk factors for total and cardiovascular mortality
A large prospective cohort study (MCCS) found that a more pro-inflammatory dietary pattern (DII) and a Mediterranean-like diet (MDS) are associated with higher total and cardiovascular mortality, with the Mediterranean pattern showing inverse associations; DII did not outperform…
DOI: 10.1016/j.numecd.2018.01.010 -
The Mediterranean-style diet for the prevention of cardiovascular diseases
Mediterranean-style diet reduces cardiovascular disease risk and mortality, supported by randomized trials showing recurrence risk reductions after myocardial infarction and lower sudden cardiac death, along with observational data linking high diet adherence to improved surviva…
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Mediterranean diet and health: A systematic review of epidemiological studies and intervention trials
This is a comprehensive systematic review of epidemiological studies and randomized trials assessing the Mediterranean diet (MedDiet) and health, finding generally favorable associations with reduced cardiovascular disease risk, diabetes incidence, cancer risk, better brain func…
DOI: 10.1016/j.maturitas.2020.03.008 -
Adherence to Three Mediterranean Dietary Indexes and All-Cause, Cardiovascular, and Cancer Mortality in an Older Mediterranean Population
Among 903 adults aged 65 and older from two Spanish cohorts, higher adherence to two relative Mediterranean diet indexes (aMED and rMED) was associated with lower all-cause and cardiovascular mortality over a 12-year follow-up, while the energy-restricted erMEDAS showed no clear…
DOI: 10.3390/nu17182956 -
Mediterranean Diet and Incidence of and Mortality From Coronary Heart Disease and Stroke in Women
In a large prospective cohort of 74,886 women, higher adherence to a Mediterranean-style diet (measured by the Alternate Mediterranean Diet Score, aMed) was associated with a lower risk of incident coronary heart disease (CHD) and stroke and with reduced cardiovascular mortality…
DOI: 10.1161/CIRCULATIONAHA.108.816736