ABSTRACT & COMMENTARY
Does Beef Get a Bad Rap?
By Martin S. Lipsky, MD
Adjunct Professor, Institute on Aging, School of Community Health, Portland State University; Dean Emeritus, University of Illinois College of Medicine, Rockford
Dr. Lipsky is a retained consultant for Health Solutions & Strategies.
SYNOPSIS: Contrary to prevailing opinion, eating lean beef may not be bad and perhaps might even favorably affect systolic blood pressure and vascular constriction.
SOURCE: Roussell MA, et al. Effects of a DASH-like diet containing lean beef on vascular health. J Hum Hypertens 2014; June 19. [Epub ahead of print.]
Atherosclerosis is a leading cause of death in the United States and both elevated blood pressure and an unhealthy diet are considered risk factors. The American Heart Association and others recommend the Dietary Approaches to Stop Hypertension (DASH) diet as a dietary approach for reducing blood pressure and other cardiovascular disease risk factors. The DASH diet is low in saturated fatty acids and recommends that dietary carbohydrates come primarily from fruits, vegetables, and whole grains. It also recommends increasing multiple minerals (potassium, magnesium, and calcium) and fiber. As part of the DASH diet, individuals are advised to avoid or restrict beef because it is a rich source of saturated fat. However, there is little evidence about the effect on vascular health when incorporating lean beef into the DASH diet.
Roussell and colleagues studied four diets: a healthy American diet (HAD), DASH, Beef in an Optimal Lean Diet (BOLD), which is a DASH-like diet that included 4 ounces of beef per day, and BOLD+, which included 5.3 ounces of daily beef. The study used a four-period, randomized, crossover design. Subjects were assigned to each type of diet for 5 weeks with a 1 week break between each dispensed diet. The study group consisted of 36 normotensive individuals between the ages of 30-65 years. Each participant received one daily meal at the study center from Monday through Friday with the remaining meals prepackaged for off-site consumption. Compliance was monitored via self-report. Participants were allowed to consume up to 8 ounces of caffeinated beverages daily and were limited to two servings of alcohol per week. Participants could continue their current exercise regimens, but were instructed not to change their routine during the study period.
Body weight was monitored and blood pressure measured at the beginning and end of each diet period. Pulse wave changes were measured using an EndoPat technique, which can be used to assess endothelial function. It can also generate an augmentation index (AI) that correlates with arterial stiffness.
The results revealed a significant decrease in systolic blood pressure (P < 0.05) in subjects on the BOLD+ diet (111.4 ± 1.9 mmHg) vs HAD (115.7 ± 1.9 mmHg). There were no significant effects of the DASH and BOLD diets on systolic blood pressure. The AI was significantly reduced in participants on the BOLD diet (-4.1%). There were no significant effects of the dietary treatments on diastolic blood pressure or endothelial function as measured by peripheral arterial tonometry.
The authors concluded that maintaining a DASH-like diet that includes lean beef decreased systolic blood pressure in normotensive individuals and that incorporating beef in a heart healthy diet can reduce peripheral vascular constriction.
COMMENTARY
Recently, several studies have raised questions about the validity of many long-held dietary beliefs and recommendations. For example, after years of endorsing the importance of a good breakfast for losing weight, Dhurandhar and colleagues2 failed to find a difference in weight loss for those attempting to lose weight with recommending eating or skipping breakfast. An even higher-profile publication was the recent meta-analysis questioning the effects of dietary fats on heart disease.3
This study by a Penn State research team adds to the growing body of work examining long-held dietary beliefs. Their findings suggest that lean beef can play a role in a heart-healthy diet. For those patients who prefer beef to fish or chicken, this should be viewed as good news. It also adds to previous work by the same group which showed that the HAD, BOLD, and BOLD+ diets had similar effects on cholesterol when compared with the DASH diet and that these diets did not differ in their impact on glucose and insulin levels.
However, before we all head off to McDonald’s for a Big Mac, it would be wise to note that the study group consumed not only lean beef but also ate very modest portions. A 4-ounce serving of beef used in the BOLD diet is about the size of a deck of cards and probably less than the typical household or most restaurant beef servings. Any advice about consuming lean beef should be combined with advice on portion size. Other concerns before extrapolating the findings include the small sample size and the relatively short-term nature of this study. It also did not examine the impact on individuals with existing hypertension.
As the authors note, there is a need for more clinical trials to clarify the role and mechanism(s) of action of the quantity and source of protein on blood pressure and vascular health in both normotensive and hypertensive individuals. At this time, perhaps the best way to clinically apply these findings is to tell those patients who have trouble restricting their beef intake that modest amounts (and define modest!) of lean beef in the context of a DASH-like diet appear to be okay and might even be beneficial.
REFERENCES
- Roussell MA, et al. Effects of a DASH-like diet containing lean beef on vascular health. J Hum Hypertens 2014; June 19. [Epub ahead of print.]
- Dhurandhar EJ, et al. The effectiveness of breakfast recommendations on weight loss: A randomized controlled trial. Am J Clin Nutr 2014;100:507-513.
- Chowdhury R, et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: A systematic review and meta-analysis. Ann Intern Med 2014;160:398-406.
