Dietary advice aimed at reducing cardiovascular risk should focus on carbohydrate intake rather than fat intake, a European conference has been told.
A team from McMaster University, Canada, carried out an international study of diets, looking at different intakes of the macronutrients fat and carbohydrate.
In yesterday’s (29 August) Lancet they write: "The relationship between macronutrients and cardiovascular disease and mortality 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 findings were also being reported at the conference of the European Society of Cardiology in Barcelona, Spain.
Dr Mahshid Dehghan and the team examined figures on 135,335 male and female adults in 18 countries, followed up for about seven years. Food intake was measured using standard questionnaires. During follow up there were 5,796 deaths and 4,784 diagnoses of major cardiovascular disease.
Analysis showed that higher carbohydrate intake was linked to a higher overall mortality. Those in the highest fifth for carbohydrate intake had a 28% higher risk than those in the lowest fifth. However there was no link to cardiovascular disease or death from cardiovascular disease.
Looking at fat intake, those in the highest fifth had a 23% lower risk of overall death than those in the lowest fifth.
Types of fat were then examined separately. This showed that a high saturated fat intake was associated with lowered risk of overall mortality – a 14% reduction for those eating the most saturated fat and a 20% reduction for those eating polyunsaturated fat.
The authors write: "Global dietary guidelines should be reconsidered in light of these findings."
Dr Dehghan adds: "The current focus on promoting low-fat diets ignores the fact that most people’s diets in low and middle income countries are very high in carbohydrates, which seem to be linked to worse health outcomes. Our study did not look at trans fats, typically from processed foods, and the evidence is clear that these are unhealthy."
She told conference delegates: “Limiting total fat consumption is unlikely to improve health in populations – and a total fat intake of about 35% of energy with concomitant lowering of carbohydrate intake may lower risk of total mortality.
"In fact, individuals with high carbohydrate intake, above 60% of energy, may benefit from a reduction in carbohydrate intake and increase in the consumption of fats.”
* Eating extra virgin olive oil enriched-dark chocolate could benefit the cardiovascular system, Italian researchers told the conference.
Dr Rossella Di Stefano of the University of Pisa, Italy, and her team point out that chocolate may have a functional effect on the body due to its high level of flavanols, namely cathechins and procyanidins.
The team recruited 26 men and women who had at least three of the following cardiovascular risk factors: smoking, dyslipidaemia, hypertension, or family history of cardiovascular disease. Participants were given 40 grams of dark chocolate every day for four weeks. For two weeks it contained 10% extra virgin olive oil and for 14 consecutive days it contained 2.5% apple extract.
Tests were given to indicate the progression of atherosclerosis, by measuring metabolic changes. These tests included levels of the metabolic compounds carnitine and hippurate, blood lipids, blood pressure and levels of circulating endothelial progenitor cells which are critical for vascular repair and maintenance of endothelial function.
At the end of the study, a link was seen between the olive oil chocolate and higher levels of endothelial progenitor cells, as well as lower carnitine and hippurate levels.
"Olive oil-enriched chocolate was associated with significantly increased high-density lipoprotein cholesterol and decreased blood pressure compared to baseline," say the researchers, presenting the work yesterday (29 August) at the European Society of Cardiology Congress 2017 held in Barcelona, Spain.
Dr Di Stefano says: "We found that small daily portions of dark chocolate with added natural polyphenols from extra virgin olive oil was associated with an improved cardiovascular risk profile. Our study suggests that extra virgin olive oil might be a good food additive to help preserve our repairing cells."
Dehghan, M. et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. The Lancet 29 August 2017; doi: 10.1016/S0140-6736(17)32252-3 [abstract]
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