Wayne Campbell, Purdue University – Eating Red Meat

Is eating red meat bad for you?

Wayne Campbell, professor of nutrition science at Purdue University, delves into this question.

Our research interests include human nutrition and exercise studies on protein, carbohydrate and energy metabolism, dietary protein and energy requirements, body composition, obesity, weight loss, muscle strength, and muscle function with special emphasis on aging. We are also interested in how nutrition, exercise, and aging impact appetite and ingestive behaviors. Our recent research suggests that older people who habitually consume the Recommended Dietary Allowance for protein experience subtle declines in skeletel muscle size. Thus we seek to find the optimal protein intake for older and elderly people to consume. Our research also focuses on how protein metabolism, body composition, and glucose metabolism change in older people with changes in protein intake, body weight, and exercise (especially strength training). We are also interested in evaluating the effectiveness of compounds that are promoted to have ergogenic properties. The potential importance of the physical form of food (e.g. liquid versus solid) on appetite, ingestive behaviors, energy balance, and body weight control is also of great interest to our research team.

Our research includes the use of traditional metabolic balance techniques (with strict dietary control possible in a metabolic research kitchen), stable isotope infusion techniques (to measure in vivo acid turnover and incorporation into muscle tissues), whole body composition (hydrostatic weighing, plethysmography, dual x-ray absorptiometry, deuterium oxide dilution), the muscle biopsy technique (to obtain small samples of human skeletal muscle), and indirect calorimetry (to measure resting and exercise energy expenditure). We also highly value collaboration within and outside of Purdue to expand our interests, expertise, and research capabilities, as become available.

Eating Red Meat

Organizations that promote healthy eating often recommend consuming no more than about three and a half 2-3 oz. servings of red meat per week. This recommendation is mainly based on observational studies that relate peoples’ eating habits over time to whether or not they develop or die from cardiovascular disease. Observational studies do not determine if eating red meat causes cardiovascular disease. Conducting clinical trials allows scientists to isolate red meat as an independent variable and assess its causal effects on cardiovascular disease risk factors. Ethically and practically, clinical trials are not used to assess dependent variables such as disease onset or death. Therefore, both observational and clinical studies have strengths that make them an integral component in setting dietary recommendations.

Because the evidence base for red meat and cardiovascular health is mainly observation data, our lab compiled data from clinical trials assessing the consumption of more than three and a half servings of total red meat per week on blood total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and blood pressure. These are common measures taken by clinicians to help determine patients’ risk for developing cardiovascular disease. Results from the 24 qualified clinical trials support that the amount of red meat consumed weekly, mainly unprocessed beef and pork, does not influence cardiovascular disease risk factors. Our results should not be used to encourage people to eat higher amounts of red meat but are consistent with dietary guidance encouraging the consumption of a variety of protein-rich foods as part of a healthy diet. Future research is needed to investigate the effects of red meat consumption on other cardiovascular disease risk factors, such as indexes of type 2 diabetes and chronic inflammation.