Impact of Lean Red Meat in Mediterranean Diets on Heart Health
Study Overview
A recent controlled nutrition study investigated the effects of including lean, unprocessed red meat in a Mediterranean-style diet on its benefits for heart health. The Mediterranean diet, recognized for its heart-healthy advantages, emphasizes a high intake of fruits, vegetables, and olive oil as the primary fat source, while traditionally being low in red meat.
Background
For decades, health professionals have advocated for a Mediterranean diet, particularly for individuals at risk of heart disease. This dietary pattern is often combined with recommendations for reduced red meat consumption. However, emerging research indicates that incorporating lean, unprocessed red meat may enhance heart health by positively influencing risk factors associated with heart disease.
Research Methodology
Conducted in Texas, the study aimed to evaluate how varying amounts of lean, unprocessed red meat within a Mediterranean diet affect heart disease risk factors. The findings were published in the American Journal of Clinical Nutrition. The research involved 41 overweight or obese participants, with a mean age of 46 years.
The study was structured over 16 weeks, with participants randomly assigned to one of two Mediterranean-style diets for the first five weeks: the “Med-Red” diet, which included 500 grams of lean unprocessed red meat (beef or pork) weekly—reflecting typical consumption in the U.S.—or the “Med-Control” diet, which allowed for only 200 grams of lean unprocessed red meat per week, aligning with heart-healthy eating guidelines. The Med-Control diet included additional protein sources such as poultry to compensate for the reduced red meat intake.
After a four-week “wash-out” period, participants returned to their normal diets before switching to the alternate Mediterranean diet for the final five weeks. Controlled meals with detailed menus were provided throughout the study.
Results
The researchers measured several heart disease risk factors, including body weight, blood pressure, blood lipids, glucose, and insulin levels, at the beginning and end of each five-week intervention.
The results indicated that body weight decreased more significantly with the Med-Red diet compared to the Med-Control diet, although the reductions were modest. Body fat percentage remained unchanged for both diets. Improvements in blood pressure were observed across both diet groups, with the exception of during sleep.
Total cholesterol levels decreased more substantially in participants following the Med-Red diet, while LDL (“bad cholesterol”) levels dropped with the Med-Red diet but remained unchanged in the Med-Control group. Both diets experienced a minor reduction in HDL cholesterol. Other metrics, including triglycerides, total cholesterol/HDL ratio, glucose, and insulin, showed no significant changes in either diet group.
Conclusions
The researchers concluded that overweight adults could improve various heart disease risk factors by adhering to a Mediterranean-style diet, regardless of whether red meat intake is reduced, provided the meat is lean and unprocessed. These findings corroborate previous studies suggesting that the consumption of unprocessed red meat does not elevate the risk of developing heart disease.
Reference
O’Connor LE, Paddon-Jones D, Wright AJ, et al. A Mediterranean-style eating pattern with lean, unprocessed red meat has cardiometabolic benefits for adults who are overweight or obese in a randomized, crossover, controlled feeding trial. Am J Clin Nutr 2018;108:33-40.