Red Meat Consumption And Mortality

Abstract

Red meat consumption has been associated with an increased risk of chronic diseases. However, its relationship with mortality remains uncertain. We prospectively observed 37 698 men from the Health Professionals Follow-up Study (1986-2008) and 83 644 women from the Nurses’ Health Study (1980-2008) who were free of cardiovascular disease (CVD) and cancer at baseline. Diet was assessed by validated food frequency questionnaires and updated every 4 years. We documented 23 926 deaths (including 5910 CVD and 9464 cancer deaths) during 2.96 million person-years of follow-up. After multivariate adjustment for major lifestyle and dietary risk factors, the pooled hazard ratio (HR) (95% CI) of total mortality for a 1-serving-per-day increase was 1.13 (1.07-1.20) for unprocessed red meat and 1.20 (1.15-1.24) for processed red meat. The corresponding HRs (95% CIs) were 1.18 (1.13-1.23) and 1.21 (1.13-1.31) for CVD mortality and 1.10 (1.06-1.14) and 1.16 (1.09-1.23) for cancer mortality. We estimated that substitutions of 1 serving per day of other foods (including fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1 serving per day of red meat were associated with a 7% to 19% lower mortality risk. We also estimated that 9.3% of deaths in men and 7.6% in women in these cohorts could be prevented at the end of follow-up if all the individuals consumed fewer than 0.5 servings per day (approximately 42 g/d) of red meat. Red meat consumption is associated with an increased risk of total, CVD, and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.

Generated Summary

This research article, published in the “Archives of Internal Medicine” in 2012, presents the findings of two prospective cohort studies, the Health Professionals Follow-up Study (HPFS) and the Nurses’ Health Study (NHS). The studies aimed to investigate the association between red meat consumption and mortality risk. The HPFS, initiated in 1986, followed 37,698 men, while the NHS, starting in 1980, tracked 83,644 women. Both studies assessed participants’ diets using validated food frequency questionnaires, updated every four years, and documented deaths over a follow-up period of up to 28 years. The primary methodology involved prospectively observing participants, collecting dietary data, and analyzing the relationship between red meat intake and total, cardiovascular disease (CVD), and cancer-specific mortality. The study also examined the effects of substituting other protein sources for red meat on mortality risks.

Key Findings & Statistics

• The study documented 23,926 deaths during the follow-up period, including 5,910 CVD deaths and 9,464 cancer deaths.
• For a 1-serving-per-day increase in unprocessed red meat consumption, the pooled hazard ratio (HR) for total mortality was 1.13 (95% CI, 1.07-1.20).
• For processed red meat, the HR for total mortality was 1.20 (95% CI, 1.15-1.24) for a 1-serving-per-day increase.
• The HRs (95% CIs) for CVD mortality were 1.18 (1.13-1.23) and 1.21 (1.13-1.31) for unprocessed and processed red meat, respectively.
• The HRs (95% CIs) for cancer mortality were 1.10 (1.06-1.14) and 1.16 (1.09-1.23) for unprocessed and processed red meat, respectively.
• Substitution of 1 serving per day of other foods (fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1 serving per day of red meat was associated with a 7% to 19% lower mortality risk.
• It was estimated that 9.3% of deaths in men and 7.6% in women could be prevented if all individuals consumed fewer than 0.5 servings per day (approximately 42 g/d) of red meat.
• In the HPFS, with up to 22 years of follow-up (758,524 person-years), 8,926 deaths were documented, of which 2,716 were CVD deaths and 3,073 were cancer deaths.
• In the NHS, with up to 28 years of follow-up (2,199,892 person-years), 15,000 deaths were documented, of which 3,194 were CVD deaths and 6,391 were cancer deaths.
• Men and women with higher intakes of red meat were less likely to be physically active and more likely to be smokers, to drink alcohol, and to have a higher body mass index.
• When treating red meat intake as a continuous variable, the elevated risk of total mortality in the pooled analysis for a 1-serving-per-day increase was 12% (HR, 1.12; 95% CI, 1.09-1.15) for total red meat, 13% (HR, 1.13; 95% CI, 1.07-1.20) for unprocessed red meat, and 20% (HR, 1.20; 95% CI, 1.15-1.24) for processed red meat.
• The HRs (95% CIs) for CVD mortality were 1.16 (1.12-1.20) for total red meat, 1.18 (1.13-1.23) for unprocessed red meat, and 1.21 (1.13-1.31) for processed red meat.
• The HRs (95% CIs) for cancer mortality were 1.10 (1.07-1.13) for total red meat, 1.10 (1.06-1.14) for unprocessed red meat, and 1.16 (1.09-1.23) for processed red meat.
• We estimated that 9.3% (95% CI, 5.9%-12.7%) in men and 7.6% (95% CI, 3.5%-11.7%) in women of total deaths during follow-up could be prevented if all the participants consumed fewer than 0.5 servings per day of total red meat in these cohorts; the estimates were 8.6% (95% CI, 2.3%-14.7%) in men and 12.2% (95% CI, 3.3%-21.0%) in women for CVD deaths.
• The mean daily intake of unprocessed red meat dropped from 0.75 to 0.63 servings from 1986 to 2006 in men and from 1.10 to 0.55 servings from 1980 to 2006 in women.

Other Important Findings

• The study found that the associations between red meat and CVD mortality were moderately attenuated after additional adjustment for heme iron, suggesting that heme iron intake may partially explain this association.
• During the follow-up, red meat intake declined in both men and women.
• The association between red meat intake and risk of total mortality was linear.
• Replacing 1 serving of total red meat with 1 serving of fish, poultry, nuts, legumes, low-fat dairy products, or whole grains daily was associated with a lower risk of total mortality.

Limitations Noted in the Document

• The study’s findings may be limited by the fact that the participants were predominantly non-Hispanic white health professionals.
• Measurement errors in dietary assessments were inevitable, including misclassification of ham or cold cuts as unprocessed red meat and inaccurate assessment of red meat content in mixed dishes.
• Because of the prospective study design, any measurement errors of meat intake are independent of study outcome ascertainment and, therefore, are likely to attenuate the associations toward the null.
• The analyses using baseline diet only yielded weaker associations.
• The generalizability of the observed associations may be limited to similar populations.

Conclusion

The research conclusively demonstrates that red meat consumption is associated with a significantly increased risk of total, CVD, and cancer mortality. Both unprocessed and processed red meats contribute to this elevated risk, with processed meats showing a stronger association. The study’s findings indicate a dose-response relationship, where higher red meat intake correlates with increased mortality. A particularly notable insight is the benefit derived from substituting red meat with alternative protein sources. Replacing red meat with fish, poultry, nuts, legumes, low-fat dairy, or whole grains resulted in a lower risk of overall mortality. These substitutions, the study indicates, can potentially reduce mortality risks, providing a clear health benefit. The study’s findings are supported by the dose-response relationship and the reduction of risk with the substitution of healthier food options, underscoring the importance of dietary choices. This prospective cohort study offers robust evidence supporting the adverse health impacts of red meat consumption and the benefits of incorporating plant-based and other protein-rich foods into the diet. The study underscores that dietary interventions focusing on reducing red meat intake and increasing the consumption of healthier alternatives can improve long-term health outcomes.

DOI

10.1001/archinternmed.2011.2287