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PURE: Moderate red meat, dairy intake may help reduce mortality, CV risk
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MUNICH — A new diet quality tool based on an analysis of more than 218,000 adults worldwide suggests that increased intake of unprocessed red meat, fish and whole fat dairy can reduce risk for all-cause mortality, MI and stroke, according to new data from the PURE study presented at the European Society of Cardiology Congress.
The findings, an analysis of five large, international cohorts, differ from current advice derived from earlier studies performed in predominantly high-income countries, which suggested an association between dairy products, red meat consumption and CV and mortality risk, said Andrew Mente, PhD, MA, a principal investigator for the epidemiology program at the Population Health Research Institute.
“Most data on diet and health are from North America, Europe, China and Japan, and there is consensus is that fruits and vegetables are protective,” Mente said during a press conference here. “Recent cohort studies with all geographic regions of the world, including South America, the Middle East, Africa and South Asia indicate that moderate intakes of whole fat dairy, unprocessed meats, fish and nuts are protective, while a diet high in starch is harmful.”
Mente and colleagues analyzed broad patterns of diet quality in 138,527 people aged 35 to 70 years without CVD disease from the PURE study (21 countries). Findings were then validated in 31,546 patients with vascular disease from the ONTARGET and TRANSCEND studies (40 countries; n = 31,546), 27,098 patients with a first MI from the INTERHEART study (52 countries; case-control design) and 20,834 patients with a first stroke from the INTERSTROKE study (36 countries; case-control design).
The PURE healthy diet score, Mente said, was based on intake of foods that were associated with a lower risk for mortality in the PURE cohort of 138,000 adults. Included foods were vegetables, fruit, legumes, nuts, fish, dairy and unprocessed red meat. Each food was assigned a score of 1 (lowest) through 5 (highest), based on intake quintiles. Total diet score was based on the unweighted sum of each protective food with a maximum score of 35. The reference quintile included adults with a diet quality score of 11; the highest quintile included adults with a diet quality score of 18.
A low PURE diet score, Mente said, would typically include low intake of fruits and vegetables, less than one daily serving of nuts and legumes, approximately half a daily serving of dairy and very little red meat and fish — translating to a diet where 69% of energy intake comes from carbohydrates.
“Conversely, a high-quality diet includes a high amount of fruits and vegetables, two to three servings of nuts and legumes, three servings of dairy, one and a half servings of red meat, and fish about twice a week,” Mente said. “This is generally a more balanced diet with moderate amounts of carbohydrates, fats and protein.”
During a median follow-up of 9.1 years in PURE, researchers observed 6,821 non-CV deaths and 5,466 major CV events, defined as CV death, nonfatal MI, stroke and HF.
In a model adjusted for multiple factors including age, sex, education, waist-to-hip ratio and diabetes status, adults in the highest quintile of the PURE cohort experienced a 25% reduced risk for non-CV mortality compared with adults in the lowest quintile, (HR = 0.75; 95% CI, 0.68-0.93), as well as a modest reduction in major CV events (HR = 0.91; 95% CI, 0.81-1.02). A greater risk reduction for major CV events was observed in the ONTARGET cohort (HR = 0.86; 95% CI, 0.78-1.05), whereas findings to total mortality were similar, Mente said.
In adjusted analyses for the INTERHEART cohort, researchers observed 22% decreased odds for MI among adults in the highest quintile for diet quality score vs. those in the lowest quintile, Mente said (OR = 0.78; 95% CI, 0.71-0.85), in addition to a similarly reduced risk for stroke among adults in the highest quintile of the INTERSTROKE cohort vs. those in the lowest diet score quintile (OR = 0.75, 95% CI 0.68–0.84).
“There is consistency across four international studies,” Mente said, noting the findings are globally applicable. “You see different designs in over 218,000 people, and consistency in those with and without vascular disease.”
In a discussion following the study presentation, Eva Prescott, MD, DMSc, of the department of cardiology at Bispebjerg Hospital and the University of Copenhagen, said the size, global design and large variation in food patterns were strengths for the PURE study; however, there is uncertainty as to whether the PURE diet quality score captures the many facets of diet.
“It is possible that we can’t use the same diet score all over the world, because there are so many different food patterns,” Prescott said.
In 2017 analyses from the PURE trial published in The Lancet and The Lancet Diabetes and Endocrinology and reported by Cardiology Today, researchers found that diets based on global guidelines, which typically limit carbohydrate and total fat intake while increasing the intake of fruits, vegetables and legumes, did not have an impact on CVD and total mortality. The researchers found elevated carbohydrate intake was associated with adverse outcomes, three or four servings per day of fruits and vegetables was associated with positive outcomes and elevated fat intake was associated with reduced mortality risk.
Mente said the PURE study is continuing and individual outcomes continue to be analyzed. – by Regina Schaffer
Reference:
Mente A. Hot Line Session 4. Presented at: European Society of Cardiology Congress; Aug. 25-29, 2018; Munich.
Disclosure: The study was funded by the PHRI, Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario and unrestricted grants from several pharmaceutical companies, as well as by grants from the health agencies or ministries of over 40 countries. Mente reports no relevant financial disclosures.
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Kim Allan Williams Sr., MD, MACC, FAHA, MASNC
The real value with this study is to get everyone to recognize that there is a direct correlation between food intake — quantity, quality and substance — and CV events and death. If everyone recognized that, it could change the world.
The real strength of this study is that it includes many countries and many patients, and the investigators were able to develop an analytic model from the data. But the question is whether the model represents the healthier diet in a relative sense or the optimum diet? For example, this model diet includes red meat and fish, which may be better than refined carbohydrates and processed meats. But recent published studies indicated that both of those foods increase mortality.
There are still questions to be answered. I would like to see a model that assesses intake of fruits and vegetables only and see how that compares to the model that includes animal products that are more subject to controversy because of their association with MI, stroke, HF and overall mortality. This is not a perfect model; however, what I like about this is that I can give the patient sitting in the waiting room a food questionnaire, and then give them a score based on this that you can hand to them, saying, “Here is how your score of what you’re eating correlates with your likelihood of dying.” That’s a very powerful tool to have.
Cardiology Today Editorial Board Member
Rush University Medical Center
Past President, American College of Cardiology
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