The foods that make up a heart healthy diet for people worldwide may differ from what was previously thought, according to late breaking results from the observational Prospective Urban Rural Epidemiological (PURE) study presented at ESC Congress 2018. Professor Salim Yusuf, senior author and director of the Population Health Research Institute (PHRI) at McMaster University in Hamilton, Canada, said: “Thinking on what constitutes a high-quality diet for a global population needs to be reconsidered. For example, our results show that dairy products and meat are beneficial for heart health and longevity. This differs from current dietary advice.”
Recommendations for a high-quality diet to avoid cardiovascular disease are largely based on studies conducted decades ago in high income countries. There is little information on what people eat today across the world.
This study aimed to clarify the constituents of a modern and international diet that promotes heart health and longevity. A dietary quality score was developed based on foods associated with a lower risk of death in previous studies (fruit, vegetables, nuts, legumes, fish, dairy products, and meat).
Participants of five studies including more than 218,000 people from over 50 countries in five continents were divided into five groups according to the quality of their diet. The risks of cardiovascular disease and death in those with the highest quality diet (18 points or more) were compared to those with the poorest quality diet (11 points or less).
“People who consumed a diet emphasising fruit, vegetables, nuts, legumes, fish, dairy products, and meat had the lowest risks of cardiovascular disease and early death,” said co-principal investigator Dr Andrew Mente, of the PHRI. “Regarding meat, we found that unprocessed meat is associated with benefit.”
The results suggest that we should limit the amount of refined carbohydrates we eat and that dairy foods and unprocessed meat can be included as part of a healthy diet.
Co-principal investigator Dr Mahshid Dehghan, also a PHRI investigator, added: “Our results appeared to apply to people from different parts of the world and so the findings are globally applicable.”
To conduct the study, the association between diet quality, cardiovascular disease and death was first examined in 138,527 people aged 35 to 70 years without cardiovascular disease from the PURE study. It was then validated in 31,546 patients with vascular disease from the ONTARGET and TRANSCEND studies, 27,098 patients with a first heart attack from the INTERHEART study, and 20,834 patients with a first stroke from the INTERSTROKE study.
During a median follow-up of 9.1 years in PURE, there were 6,821 deaths and 5,466 major cardiovascular events (death from cardiovascular causes, nonfatal myocardial infarction, stroke, heart failure). After adjusting for factors that could influence the relationship, compared with the poorest quality diet, the highest quality diet was associated with significantly lower risks of major cardiovascular events (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.80–1.00, p=0.0193), stroke (HR 0.83, 95% CI 0.71–0.97, p=0.0402), cardiovascular death (HR 0.71, 95% CI 0.59–0.85, p<0.0001), non-cardiovascular death (HR 0.74, 95% CI 0.66–0.84; p<0.0001), and total deaths (HR 0.75, 95% CI 0.68–0.83, p<0.0001).
Similar results were found in patients with vascular diseases in ONTARGET and TRANSCEND. The highest quality diet was associated with significantly lower risks of major cardiovascular events (HR 0.86, 95% CI 0.78–0.94), cardiovascular death (HR 0.79, 95% CI 0.69–0.91), non-cardiovascular death (HR 0.89, 95% CI 0.75–1.05), and total deaths (HR 0.75, 95% CI 0.67–0.83).
In the INTERHEART and INTERSTROKE studies, the highest quality diet was associated with a lower risk of myocardial infarction (odds ratio [OR] 0.77, 95% CI 0.70–0.84) and stroke (OR 0.78, 95% CI 0.70–0.86), respectively.