SOURCE: Dehghan M, Mente A, Zhang X, et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): A prospective cohort study. Lancet 2017;390:2050-2062.

Opinions about how to best structure optimum dietary constituents have gone through multiple dramatic changes in the last three decades, with little consistency. Remember when eggs were bad because of cholesterol, and margarine was preferred to butter because of calories and fat, and fat, generally, was regarded as an anathema?

The Prospective Urban Rural Epidemiology study was an observational cohort (n = 135,335) of adults aged 35-70 years, followed for 7.4 years, representing 18 different countries, selected to represent the three tiers of low-, middle-, and high-income nations.

During the follow-up interval, 5,796 deaths and 4,784 nonfatal cardiovascular events occurred. Overall for carbohydrates, comparing the highest quintile of intake to the lowest (quintile 5 vs. quintile 1), the hazard ratio for mortality was 1.28. Perhaps surprisingly, carbohydrate levels were not associated with mortality from cardiovascular disease or with cardiovascular events. Additionally, somewhat contrary to the prevailing wisdom, intake of total fat was inversely associated with total mortality (hazard ratio, 0.77). Even the much-maligned saturated fat in the diet was associated with a reduced hazard ratio for total mortality (0.86). Each of these outcomes was statistically significant.

The authors’ interpretation of their results, as quoted, is appropriate: “Global dietary guidelines should be reconsidered in light of these findings.”