Abstract
OBJECTIVES To study total, processed, and unprocessed red meat in relation to risk of coronary heart disease (CHD) and to estimate the effects of substituting other protein sources for red meat with CHD risk. DESIGN Prospective cohort study with repeated measures of diet and lifestyle factors. SETTING Health Professionals Follow-Up Study cohort, United States, 1986-2016. PARTICIPANTS 43 272 men without cardiovascular disease or cancer at baseline. MAIN OUTCOME MEASURES The primary outcome was total CHD, comprised of acute non-fatal myocardial infarction or fatal CHD. Cox models were used to estimate hazard ratios and 95% confidence intervals across categories of red meat consumption. Substitution analyses were conducted by comparing coefficients for red meat and the alternative food in models, including red meat and alternative foods as continuous variables. RESULTS During 1023872 person years of follow-up, 4456 incident CHD events were documented of which 1860 were fatal. After multivariate adjustment for dietary and non-dietary risk factors, total, unprocessed, and processed red meat intake were each associated with a modestly higher risk of CHD (hazard ratio for one serving per day increment: 1.12 (95% confidence interval 1.06 to 1.18) for total red meat, 1.11 (1.02 to 1.21) for unprocessed red meat, and 1.15 (1.06 to 1.25) for processed red meat). Compared with red meat, the intake of one serving per day of combined plant protein sources (nuts, legumes, and soy) was associated with a lower risk of CHD (0.86 (0.80 to 0.93) compared with total red meat, 0.87 (0.79 to 0.95) compared with unprocessed red meat, and 0.83 (0.76 to 0.91) compared with processed red meat). Substitutions of whole grains and dairy products for total red meat and eggs for processed red meat were also associated with lower CHD risk. CONCLUSIONS Substituting high quality plant foods such as legumes, nuts, or soy for red meat might reduce the risk of CHD. Substituting whole grains and dairy products for total red meat, and eggs for processed red meat, might also reduce this risk.
Generated Summary
This is a prospective cohort study that investigates the relationship between red meat intake and the risk of coronary heart disease (CHD) among US men. The study utilized repeated measures of diet and lifestyle factors from the Health Professionals Follow-Up Study cohort, spanning from 1986 to 2016. The primary outcome was total CHD, encompassing acute non-fatal myocardial infarction or fatal CHD. Cox models were employed to estimate hazard ratios and 95% confidence intervals across categories of red meat consumption. Additionally, substitution analyses were conducted to assess the effects of replacing red meat with other protein sources on CHD risk. The study included 43,272 men who were initially free of cardiovascular disease or cancer. The main objective was to determine the association of total, processed, and unprocessed red meat intake with the risk of CHD and to evaluate the impact of substituting red meat with alternative protein sources on CHD risk.
Key Findings & Statistics
- During 1,023,872 person-years of follow-up, 4,456 incident CHD events were documented.
- Total, unprocessed, and processed red meat intake were each associated with a higher risk of CHD: hazard ratio for one serving per day increment: 1.12 (95% confidence interval 1.06 to 1.18) for total red meat, 1.11 (1.02 to 1.21) for unprocessed red meat, and 1.15 (1.06 to 1.25) for processed red meat.
- Compared with red meat, the intake of one serving per day of combined plant protein sources (nuts, legumes, and soy) was associated with a lower risk of CHD: 0.86 (0.80 to 0.93) compared with total red meat, 0.87 (0.79 to 0.95) compared with unprocessed red meat, and 0.83 (0.76 to 0.91) compared with processed red meat.
- Substitutions of whole grains and dairy products for total red meat and eggs for processed red meat were also associated with lower CHD risk.
- For total red meat, an increment of one serving per day was associated with a 12% (95% confidence interval 6% to 18%) higher risk of CHD.
- Associations of each of total, unprocessed, and processed red meat with fatal CHD were slightly stronger (1.38 (1.15 to 1.66) for total red meat, 1.29 (1.08 to 1.53) for unprocessed red meat, and 1.21 (1.02 to 1.43) for processed red meat).
- Compared with intakes of total, unprocessed, or processed red meat, intakes of nuts, legumes, soy, and combined plant protein sources (nuts, legumes, and soy) were each associated with a significantly lower risk of CHD.
- Intake of high fat dairy products, low fat dairy products, and whole grains were also associated with a lower CHD risk compared with intake of total, unprocessed, and processed red meat.
- Egg intake was additionally associated with a lower CHD risk compared with intake of processed red meat (0.87 (0.76 to 0.99)).
- Milk (both skimmed and whole), yogurt, and cheese were each associated with a 10% to 22% lower risk of CHD compared with red meat.
- In age adjusted analyses, higher intakes of total red meat, unprocessed red meat, and processed red meat were each positively associated with higher risk of CHD.
- After further adjustment for non-dietary cardiovascular disease risk factors and energy intake, the associations of total, processed, and unprocessed red meat consumption with CHD risk each remained statistically significant but attenuated.
- For an increment of one serving per day, total red meat was associated with a 12% higher risk of CHD.
Other Important Findings
- Associations between red meat and CHD risk became slightly weaker after including baseline history of diabetes, hypertension, and hypercholesterolemia in the model.
- The associations comparing specific protein sources in relation to risk of CHD did not differ by BMI (<25, ≥25) or period (<2000, ≥2000).
- Stronger associations were observed in the comparisons of nuts and plant based proteins with red meat among older men and was attenuated but remained significant among those with low fiber intake.
- The associations between red meat and egg intake were stronger among younger men in whom the replacement of red meat with egg was associated with a 20% (95% confidence interval 2% to 35%) lower risk of CHD.
- The replacement of red meat with total fish was not associated with CHD risk. However, intake of dark meat fish was inversely associated with CHD risk compared with intake of red meat in 2000 and later.
- The associations observed in the substitution analyses did not seem to diminish with up to 20 years of latency; with greater than 20 years, the associations tended to be weaker, but the number of events was relatively small.
Limitations Noted in the Document
- Measurement error in dietary assessment could lead to inaccurate assessment or misclassification bias, which may underestimate the true associations.
- The observational nature of the study limits the ability to establish causality.
- The study population consisted mainly of non-Hispanic white men, potentially limiting the generalizability of the results to other populations.
- Reverse causation bias is a possibility.
- The study design was not able to account for correlation of intakes over time.
Conclusion
The study provides strong evidence supporting the association between red meat intake and an increased risk of CHD. The findings underscore the benefits of substituting red meat with plant-based protein sources, whole grains, and dairy products to reduce CHD risk. This research suggests that substituting high-quality plant foods such as legumes, nuts, or soy for red meat might reduce the risk of CHD. The study recommends substituting whole grains and dairy products for total red meat, and eggs for processed red meat, might also reduce this risk. The study emphasizes the importance of considering the impact of dietary choices, particularly red meat consumption, on cardiovascular health. The findings support public health recommendations to limit red meat intake and promote the consumption of plant-based protein sources. The results suggest that the risk of CHD could be reduced by dietary modifications. The results suggest that the risk of CHD could be reduced by dietary modifications that favor plant-based protein sources over red meat. The study’s conclusions align with other research highlighting the health benefits of plant-based diets and the potential adverse effects of red meat consumption. The long-term follow-up and detailed dietary assessments provide robust evidence to inform dietary guidelines and public health strategies aimed at reducing CHD risk.