Can beef fit in a heart-healthy diet? Review provides new insights

While beef diets slightly raise LDL-cholesterol, they don’t significantly affect most heart health indicators, opening the door for balanced discussions on red meat’s role in nutrition.

Study: Beef Consumption and Cardiovascular Disease Risk Factors: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Image Credit: Alexander Raths / Shutterstock

In a recent systematic review and meta-analysis of randomized controlled trials published in the journal Current Developments in Nutrition, researchers reviewed data on the effects of minimally or unprocessed beef intake on cardiovascular disease (CVD) risk factors in adults.

Background

Red meat, including beef, pork, lamb, and others, is defined by its higher myoglobin content, giving it a red hue. Despite differences in nutritional composition, red meat is often grouped together in studies on cardiometabolic health, leading to generalized conclusions about its impact. Higher red meat intake has been linked to increased CVD risk in some studies, but findings are inconsistent. While dietary patterns lower in red meat show cardiovascular benefits, recent meta-analyses have found no conclusive effects of red meat on CVD risk factors. However, variations in study designs, types of red meat, and confounding lifestyle factors suggest a need for more targeted research. Further research is needed to clarify the specific impacts of different red meats.

About the Study

This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant articles were identified through a literature search of PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) databases up to January 2024, focusing on RCTs assessing the impact of beef consumption on CVD risk factors, specifically lipoprotein-related variables and blood pressures. Only RCTs involving adults with specific health conditions such as type 2 diabetes or hypertension were included, whereas studies involving other chronic diseases, children, pregnant individuals, or processed beef were excluded.

Reviewers conducted the screening and full-text reviews, with disagreements resolved through discussion. Reference lists were also reviewed to find any additional studies. Data extraction included population, intervention, comparator, outcomes, and study quality information, assessed using the Cochrane Risk of Bias tool. For meta-analysis, Comprehensive Meta-Analysis software version 3 was used. Standardized mean differences (SMDs) were employed due to differences in data reporting. Random-effect models were used to account for heterogeneity in study characteristics. Sensitivity and subgroup analyses were conducted to examine study quality, participant characteristics, and funding sources. Publication bias was assessed using funnel plots and Egger regression.

Additionally, the study disclosed its funding by Beef Checkoff, noting that while the funding body provided feedback on early study design, all final decisions rested with the researchers.

Study Results

The literature search identified 44 articles for full-text review after initially screening titles and abstracts. Of these, 35 publications were excluded from the meta-analysis primarily due to the inclusion of other red meats, such as pork and lamb, or because of insufficient specificity regarding the type of red meat included in the diet. One additional study was identified during the reference list review, resulting in 20 full-text publications included for quantitative analysis.

The meta-analysis included RCTs with higher beef intake, averaging around 161 grams per day (approximately two servings), compared to control diets that typically had no or minimal beef intake. Beef consumption had no significant impact on most lipid-related variables or lipoproteins, such as total cholesterol, High-Density Lipoprotein (HDL)-cholesterol, triglycerides, non-HDL-cholesterol, apolipoproteins A or B, Very-Low-Density Lipoprotein (VLDL)-cholesterol, or cholesterol ratios, compared with control diets. However, beef consumption did have a small but significant effect on Low-Density Lipoprotein (LDL)-cholesterol, with a standardized mean difference (SMD) of 0.11 (95% CI: 0.008, 0.20; P = 0.03), indicating slightly higher levels of LDL-cholesterol with greater beef intake.

A sensitivity analysis involving the removal of one study at a time indicated that the study by Magkos et al. influenced the observed effect on LDL cholesterol, as it utilized a very low-calorie diet (VLCD) prior to beef intake assessment. Baseline LDL-cholesterol levels were higher in the lower beef group, and by the end of the study, LDL-cholesterol levels were comparable between both groups. When baseline LDL-cholesterol values from the end of the VLCD phase were used in a post hoc sensitivity analysis, the effect of beef intake on LDL-cholesterol was attenuated (SMD: 0.09; 95% CI: -0.01, 0.19; P = 0.08).

Sensitivity analyses for other outcomes, including the removal of weight loss studies, did not show significant influences on the effect sizes. Visual inspection of funnel plots and Egger regression revealed no evidence of publication bias. Subgroup analyses demonstrated no significant effects of beef diets on lipid profile parameters except for study quality influencing LDL-cholesterol and sex influencing triglycerides. Specifically, females experienced lower triglycerides with higher beef intake (SMD: -0.19; 95% CI: -0.36, -0.01; P = 0.04). Beef intake had no significant impact on systolic or diastolic blood pressure; sensitivity analyses similarly showed no significant effects on blood pressure outcomes.

Conclusions

To summarize, this systematic review and meta-analysis of RCTs found that beef intake did not significantly impact circulating lipids, apolipoproteins, or blood pressure, with the exception of a small increase in LDL-cholesterol levels. The effect size was modest, corresponding to an approximate increase of 2.7 mg/dL in LDL-cholesterol for diets higher in beef compared to those with less or no beef, and was influenced in part by one specific study.

The researchers emphasized that additional studies should evaluate other cardiometabolic factors, such as inflammation and insulin resistance, to provide a more comprehensive understanding of beef’s impact on health. Furthermore, they highlighted the nutritional benefits of unprocessed beef, including its high-quality protein and micronutrient content, which could be incorporated into balanced diets without significantly increasing CVD risk factors.

Conflict of Interest

The study was supported by the Beef Checkoff, which provided input on initial aspects of the study design. While a report was shared with the sponsor before submission, all final decisions regarding the study and manuscript content were made independently by the research team.  Notably, researcher Kevin Maki disclosed financial support and a funding relationship with the Beef Checkoff, while the other authors reported no conflicts of interest, ensuring transparency in the research process.