No doubt many RD’s received a holiday “greetings” of sorts via an email “newsletter” from the Beef- Nutrition.org on December 15th. The email from Shalene McNeil, PhD, RD of the National Cattle- man’s Beef Association discusses a study just published in the December 2011 American Journal of Clinical Nutrition done at Penn State. One of the key “takeaways” in the “Beef Nutrition News” article states “By including lean beef daily, study participants in this randomized controlled clinical study experienced a 10% decrease in LDL-cholesterol from baseline. The “newsletter” concludes with: “This latest study on beef’s role in a heart-healthy diet provides ad- ditional science to make evidence- based recommendations.” Such statements about this study might lead some to believe eating more lean beef actually helps lower LDL-cholesterol and could even be heart healthy? In fact a close look at the study reveals that eating more lean beef had nothing to do with the modest drop in LDL- cholesterol levels observed in this study nor does this short term study tells us much about wheth- er replacing pork, poultry, and fish with lean beef would impact the risk of developing atheroscle- rosis and coronary heart disease (CAD).
The AJCN study had 36 subjects 30-65y with moderately elevated LDL-cholesterol levels consume 4 different diets for 5 weeks each. All subjects consumed each of the 4 diets in random order with a one week washout period be- tween each test diet period. All the foods for each of the 4 diets were provided by the research- ers and compliance was care- fully monitored. The changes in blood lipids and other variables of the 3 experimental diets were compared to what they called a “Healthy American Diet” (HAD). The HAD contained 33% fat calories and 12% saturated fatty acids (SFA) and 287mg of choles- terol. The two “beef in an optimal lean diets” (BOLD) and DASH diet all had 5-6% less total fat with only 6% SFA and about 100mg less cholesterol than HAD. The 2 BOLD and DASH diet all had more fiber than the HAD as well. The first BOLD was basically a DASH diet but with 3 more ounces of lean beef replacing pork, poultry, and fish. The BOLD+ diet had an additional 1.5oz (or 5.5oz/day) compared to the BOLD. BOLD+ also had much more total protein than HAD, BOLD or DASH from plant sources, nonfat dairy, and egg whites. As a result BOLD+ got 27% of its total calories from protein compared with 17%, 18%, and 19% in the HAD, DASH, and BOLD, respectively. Also com- pared to HAD, which provided 24g of fiber/day the DASH, BOLD, and BOLD+ diets provided 36, 32, and 38g of fiber/day, respectively. By design all subjects had to remain weight stable throughout the experimental period. What the results showed were quite predictable given the similar intake of SFA and cholesterol coupled with extra fiber on the DASH, BOLD, and BOLD+ diets. Compared to HAD the DASH, BOLD and BOLD+ all reduced LDL- cholesterol levels by about 6%. HDL-cholesterol levels fell about as much as LDL-cholesterol levels on all 3 experimental diets and serum triglyceride and other lipo- protein changes were statistically insignificant for the most part. There was some evidence to sug- gests the higher protein content in place of refined carbohydrate while not increasing SFA and cho- lesterol content when consuming the BOLD+ diet might have had some additional benefits on some components of the inflamma- tion process as seen earlier in the OMNI Heart Trial.
What this study clearly does not show is that replacing omega-3 rich seafood with even the lean- est red meat is heart healthy. Nor does it show that replacing beans, whole grains, fruits, and vegetables with even the leanest beef would not raise LDL-cholesterol levels and promote CAD. Clearly it would as substituting beef for whole plant foods would result in a reduction in fiber intake and an increased intake of SFA and cholesterol.
Bottom Line: What this Penn State study does show is that if one is willing to consume only the very leanest of beef while still cutting SFA and cholesterol intake just as much as on a DASH diet then short-term impact on blood lipids and other CAD risk factors will not be much different. The authors do state that: “Adhering to the BOLD and BOLD+ diets that we prepared might be challenging for consumers, at least initially, and, therefore, decreases in LDL-cholesterol concentrations would be less than expected.” True, but more importantly this study tells does not negate the growing evidence linking increased red meat intake with an increased risk of CAD, type 2 diabetes, several types of cancer, and other possible ills. Eating more beef and less plant foods would also have clear adverse effects on the environment as well. For more on this see the October 2011 Nutrition Action Health Letter.
By James J. Kenney, PhD, FACN.
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Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.