Fresh butter curls in a dish

A new study looked at dietary habits in 135,000 people around the glove and found that not all is what we have been taught for years[1].  The study looked at the controversial relationship between macronutrients and cardiovascular disease with mortality.  This relationship is controversial. Most available data are from European and North American populations where nutrition excess is more likely, so their applicability to other populations is unclear.  The results showed that a high-fat diet, including saturated fat, is associated with a reduced risk of mortality.  The PURE study followed participants from 18 countries over a 7-year span.  Researchers found that high carbohydrate intake was associated with an increased risk of mortality and heart disease risk. 

One weakness of the study is that it did not separate processed carbohydrates from unprocessed carbohydrates, but the study did find a beneficial effect of increasing consumption of fruit, vegetables, and legumes on mortality.   The maximum benefit was seen at three to four servings a day.  Also, the benefit from fruit, vegetables, and legumes was greater if they were eaten raw rather than cooked.  There was no association with an increase or lower fat or carbohydrate intake or fruit/vegetable/legume intake with major cardiovascular-disease events.

The Prospective Urban Rural Epidemiology (PURE) study is a large, epidemiological cohort study of individuals aged 35-70 years from Jan 1, 2003, to March 31, 2013, in 18 countries.  The dietary intake of 135,335 individuals was recorded using validated food frequency questionnaires.  The primary outcomes were total mortality and major cardiovascular events from fatal cardiovascular disease, non-fatal myocardial infarction, stroke, and heart failure.  Secondary outcomes were all myocardial infarctions, stroke, cardiovascular disease mortality, and non-cardiovascular disease mortality.  The researchers assessed the associations between consumption of carbohydrate, total fat, and each type of fat with cardiovascular disease and total mortality.  

During follow-up, the researchers documented 5796 deaths and 4784 major cardiovascular disease events.  Higher carbohydrate intake was associated with an increased risk of total mortality but not with the risk of cardiovascular disease or cardiovascular disease mortality. Intake of total fat and each type of fat was associated with lower risk of total mortality.  Higher saturated fat intake was associated with lower risk of stroke.  Total fat and saturated and unsaturated fats were not significantly associated with risk of myocardial infarction or cardiovascular disease mortality.

The bottom line: Higher carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.