Eating red and processed meats in any quantities may increase the risk of death from all causes, especially cardiovascular disease, found a large, 11-year cohort study. The Adventist Health Study-2 uniquely looked at the effect of low levels of intake compared to no-meat eating.
Saeed Mastour Alshahrani, lead author of the study and a doctoral student at Loma Linda University School of Public Health, said the research fills an important gap left by previous studies that looked at relatively higher levels of red meat intake and compared them with low intakes.
“A question about the effect of lower levels of intakes compared to no-meat eating remained unanswered,” Alshahrani said. “We wanted to take a closer look at the association of low intakes of red and processed meat with all-cause, cardiovascular diseases, and cancer mortality compared to those who didn’t eat meat at all.”
This study is part of the Adventist Health Study-2 (AHS-2), a prospective cohort study of approximately 96,000 Seventh-day Adventist men and women in the US and Canada. The principal investigator of AHS-2 is Dr Gary E Fraser, professor of medicine and epidemiology at Loma Linda University Health.
Adventists are a unique population – approximately 50% are vegetarians, and those who consume meat do so at low levels. This allowed researchers to investigate the effect of low levels of red and processed meat intake compared to zero-intake in a large setting such as the Adventist Health Study.
The study evaluated the deaths of over 7,900 individuals over an 11-year period. Diet was assessed by a validated quantitative food frequency questionnaire and mortality outcome data were obtained from the National Death Index. Of those individuals who consumed meat, 90% of them only ate about two ounces or less of red meat per day.
Nearly 2,600 of the reported deaths were due to cardiovascular disease, and over 1,800 were cancer deaths. Processed meat – modified to improve flavour through curing, smoking, or salting (such as ham and salami) – alone was not significantly associated with risk of mortality possibly due to a very small proportion of the population who consume such meat. However, the total intake of red and processed meat was associated with relatively higher risks of total and cardiovascular disease deaths.
Dr Michael Orlich, co-director of AHS-2 and co-author of the present study, said these new findings support a significant body of research that affirms the potential ill health effects of red and processed meats.
“Our findings give additional weight to the evidence already suggesting that eating red and processed meat may negatively impact health and lifespan,” Orlich said.
Associations of low-to-moderate consumption of red and processed meat with mortality would add to the evidence of possible adverse effects of these common foods. This study aims to investigate the association of red and processed meat intake with mortality. The Adventist Health Study-2 (AHS-2) is a prospective cohort study of ~96,000 Seventh-day Adventist men and women recruited in the US and Canada between 2002 and 2007. The final analytic sample after exclusions was 72,149. Cox proportional hazards regression was used and hazard ratios (HR) and confidence intervals (CI) were obtained. Diet was assessed by a validated quantitative food frequency questionnaire (FFQ), calibrated using six 24-h dietary recalls. Mortality outcome data were obtained from the National Death Index. During a mean follow-up of 11.8 years, there were 7961 total deaths, of which 2598 were Cardiovascular diseases (CVD) deaths and 1873 were cancer deaths. Unprocessed red meat was associated with risk of all-cause mortality (HR: 1.18; 95% CI: 1.07–1.31) and CVD mortality (HR: 1.26; 95% CI: 1.05–1.50). Processed meat alone was not significantly associated with risk of mortality. The combined intake of red and processed meat was associated with all-cause mortality (HR: 1.23; 95% CI: 1.11–1.36) and CVD mortality (HR: 1.34; 95% CI: 1.12–1.60). These findings suggest moderately higher risks of all-cause and CVD mortality associated with red and processed meat in a low meat intake population.
Saeed Alshahrani, Gary Fraser, Joan Sabaté, Raymond Knutsen, David Shavlik, Andrew Mashchak, Jan Lloren, Michael Orlich