A new study/results from various studies has been published and is on the web: http://www.beefresearch.org….it’s well worth a hard look and re-evaluation of what most people have heard about beef and its health benefits!
What follows are excerpts from that report:
LEAN BEEF AND HEART HEALTH
Cardiovascular disease (CVD) affects an estimated one in three American adults, and is a leading cause of mortality (1). It is estimated that CVD will cost the American health care system $431.8 billion in 2007 (1). Numerous risk factors are associated with CVD. These include genetics, a family history of premature CVD, cigarette/tobacco smoking, abnormal blood lipid levels (i.e., high total cholesterol and low density lipoprotein cholesterol [LDL-C], low high density lipoprotein cholesterol [HDL-C], and high triglyceride [TG] levels), hypertension, diabetes, abdominal obesity, physical inactivity, and over-consumption of alcohol (1,2).
Dietary recommendations to achieve desirable blood lipid profiles and reduce CVD risk include a reduction in total fat, saturated fat (SFA), trans fat and cholesterol (2-4). To help meet these recommendations, individuals are advised to make dietary changes, one of which is choosing lean meats over fatty meats. Unfortunately, misunderstandings about lean beef’s fat composition and lack of awareness of the growing body of scientific evidence related to lean beef and heart health have led to the unnecessary restriction of this nutrient-dense food from the diet. There is no direct evidence that lean beef consumed as part of a heart-healthy diet increases the risk of CVD (5,6). In fact, clinical trials have shown that it is unnecessary to completely substitute fish or poultry for lean red meat choices to achieve desirable blood lipid profiles (7,8). Including lean beef in a lipid lowering, heart-healthy diet plan contributes to the intake of essential nutrients such as iron, zinc, and B-vitamins and may improve acceptance of such diets due to the greater range of food choices.
Dietary Fat Recommendations to Reduce CVD
Dietary guidance from several authoritative health organizations is consistent in their recommendations to reduce the risk of CVD and improve overall health. For example, the American Heart Association (AHA) emphasizes an overall healthy diet and lifestyle to reduce the risk of CVD in the general population (2). With respect to dietary fat, the AHA recommends a total fat intake in the range of 25% to 35% of calories, <7% of calories from SFA, <1% of calories from trans fat, and <300 mg/day of cholesterol (2). Dietary SFAs (with the notable exception of stearic acid) and trans fatty acids (with the possible exception of ruminant derived trans fatty acids) raise LDL cholesterol levels, a risk factor for CVD (2). Recently, evidence-based recommendations have been released for the prevention of CVD in women (3). These guidelines encourage all women to limit SFA intake to less than 10% of calories and if possible to less than 7% of calories (3). Similarly, the Expert Panel of the National Cholesterol Education Program (NCEP) recommends that all individuals at high risk of CVD reduce total fat intake to 25% to 35% of calories, <7% of calories from SFA, and <200 mg/day of cholesterol (4).
The above recommendations are similar to those issued by the Institute of Medicine (9) and the 2005 Dietary Guidelines for Americans (10) which advise a range of total fat intake of 20% to 35% of calories, <10% of calories from SFAs, trans fatty acids as low as possible, and < 300 mg/day of cholesterol. For individuals at risk of CVD, the Dietary Guidelines recommend lower intakes (< 7% of calories) of SFAs and cholesterol (<200 mg/day) (10).
Current dietary guidance to reduce fat intake recommends a food-based approach in which foods such as fruits and vegetables, whole grains, legumes, nuts and seeds, lean meats, poultry, low-fat dairy products, and fish, especially oily fish, are encouraged at the expense of calorie dense, nutrient-poor food choices (2,10). As stated in the AHA guidelines, individuals should strive to improve their overall diet to ensure nutrient adequacy and energy balance, rather than focusing on a single nutrient or food (2).
Beef’s Nutrients
Beef’s Lipid Profile
Lean beef contains less than 10 g total fat, no more than 4.5 g of SFAs, and less than 95 mg cholesterol per 3-ounce serving, a nutrition profile that readily fits into a heart-healthy diet (11,12). Based on the AHA’s dietary fat recommendations, individuals consuming a 2,000 calorie diet are advised to consume between 56 g and 78 g of total fat and a SFA intake of 16 g or less. As noted above, a 3-ounce serving of lean beef contains levels of total fat and SFA well below these limits, and cholesterol levels below the recommendation of <300 mg/day. There currently are 29 cuts of beef which meet USDA’s labeling guidelines for lean (11-13).
The fatty acid profile of beef fat is often misunderstood. In lean beef, 54% of the fatty acids are monounsaturated (MUFA) or polyunsaturated (PUFA), which are the types favored by health professional and government agencies such as the AHA (2) and the Dietary Guidelines for Americans (10). Also, one-third of the SFAs in beef are stearic acid, which, unlike other long-chain SFAs, has been shown to be neutral in its effects on blood cholesterol levels in humans (14,15).
Emerging findings from experimental animal studies suggest that the trans fatty acid, conjugated linoleic acid (CLA), particularly rumenic acid (c9, t11, isomer) which is produced in beef, may have a favorable influence on blood lipid levels and CVD risk (17,18). However, the effects of CLA, and in particular its individual isomers, on lipid levels and CVD risk in humans remain to be determined.
Other Nutrients in Beef
Beef is an excellent source of vitamin B12 (37% of the Daily Value per 3-ounce serving) and a good source of vitamin B6 (16% of the Daily Value per 3-ounce serving). Adequate intakes of vitamin B6, vitamin B12, and the B-vitamin folic acid, are necessary to maintain optimal blood concentrations of homocyteine (2,19). Observational studies show that increased blood levels of this amino acid are associated with an increased risk of CVD (2). Increasing intake of folic acid, vitamin B6 and vitamin B12 can lower blood levels of homocysteine (20).
Although it was previously hypothesized that consumption of animal products would increase blood homocysteine levels, emerging findings from observational studies indicate that meat consumption is inversely associated with blood homocysteine levels (21-24). A randomized, controlled intervention trial found that a high protein diet rich in lean meat and dairy products did not increase blood levels of homocysteine, but rather resulted in a non-significant 25% decrease in levels compared to a low protein diet (25). More clinical trials are needed to determine whether intake of red meat such as beef lowers this potential biomarker of CVD risk.
Beef is also an excellent source of selenium (24% of the Daily Value per 3-ounce serving), a trace element with antioxidant properties. Suggestive evidence from observational studies indicates that low blood selenium concentrations are associated with increased risk of CVD (26). Findings from an on-going clinical trial in more than 32,000 men in the U.S. and Canada are anticipated to provide more conclusive evidence of selenium’s role in CVD risk (26).
Beef is a good source of iron, providing 14% of the Daily Value per 3-ounce serving. Despite the suggestion that dietary iron is a risk factor for the development of CVD (27), the Institute of Medicine has concluded that the body of evidence does not provide convincing support for a causal relationship between the level of dietary iron intake and the risk for CVD (28). Iron absorption is tightly regulated and there is little evidence that iron intakes typical of the U.S. diet lead to high iron stores in healthy individuals (29).
Interchangeability of Beef and Poultry/Fish
on Blood Lipid Levels
There is convincing evidence that lean beef has similar effects on serum lipids as chicken or fish when consumed as part of a lipid-lowering diet (7,8,35-39). In two short-term (4 to 5 weeks) randomized, controlled clinical trials, Scott and colleagues (35,36) directly compared the blood lipid responses to lean beef and chicken/fish or chicken in men with borderline or frank hypercholesterolemia.
In these studies, lean meats were incorporated into heart healthy diets containing less than 30% of calories from fat, less than 10% of calories from SFAs, and < 300 mg cholesterol, and all food during the test periods was provided to the free-living men. Similar reductions in blood total cholesterol, LDL-C, HDL-C, and TG levels were found in men consuming lean beef versus chicken, or chicken and fish (35,36). The researchers concluded that lean beef and chicken are interchangeable in the heart healthy diets.
In another study, 61 obese women consumed lean beef or chicken as the primary protein source in a calorie-reduced (500 calorie/day deficit) diet, in conjunction with a fitness walking program for 12 weeks (38). Blood total cholesterol, LDL-C, and HDL-C levels significantly decreased in both groups, but there was no difference between the beef or chicken treatments (38).
BEEF FACTS • Human Nutrition Research Lean Beef and Heart Health
References
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2. Lichtenstein, A.H., Appel, L.J., Brands, M., et al. Diet and lifestyle recommendations revision 2006. A scientific statement from the American Heart Association Nutrition Committee. Circulation 114: 82-96, 2006.
3. Mosca, L., Banka, C.L., Benjamin, E.J., et al. Evidence-based guidelines for cardiovascular disease prevention in women: 2007 update. Circulation 115: 1481-1501, 2007.
4. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 106: 3143-3421, 2002.
5. Li, D., Siriamornpun, S., Wahlqvist, M.L., et al. Lean meat and heart health. Asia Pac. J. Clin. Nutr. 14: 113-119, 2005.
6. Mann, N. Dietary lean red meat and human evolution. Europ. J. Nutr. 39: 71-79, 2000.
7. Davidson, M.H., Hunninghake, D., Maki, K.C., et al. Comparison of the effects of lean red meat vs. lean white meat on serum lipid levels among free-living persons with hypercholesterolemia. Arch. Intern. Med. 159: 1331-1338, 1999.
8. Hunninghake, D., Maki, K.C., Kwiterovich, Jr., P.O., et al. Incorporation of lean red meat into a National Cholesterol Education Program Step 1 diet: a long-term, randomized clinical trial in free-living persons with hypercholesterolemia. J. Am. Coll. Nutr. 19: 351-360, 2000.
9. Institute of Medicine of the National Academies. Dietary Reference Intakes. Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, D.C.: The National Academies Press, 2002.
10. U.S. Department of Health and Human Services, U.S. Department of Agriculture. Dietary Guidelines for Americans, 2005. Home and Garden Bulletin No. 232. Washington, D.C.: U.S. Government Printing Office, 2005. www.healthierus.gov/dietaryguidelines.
11. U.S. Department of Health and Human Services, U.S. Food and Drug Administration. FDA Backgrounder. The Food Label. May 1999. www.cfsan.fda.gov/~dms/fdnewlab.html.
12. U.S. Department of Agriculture, Agricultural Research Service. USDA Nutrient Database for Standard Reference, Release 19. 2006. www.ars.usda.gov/nutrientdata.
13. National Cattlemen’s Beef Association. Beef Facts: Beef Lipids in Perspective. Centennial, CO: National Cattlemen’s Beef Association, 2007.
14. Kris-Etherton, P.M., Griel, A.E., Psota, T.L., et al. Dietary stearic acid and risk of cardiovascular disease: intake, sources, digestion, and absorption. Lipids 40: 1193-1200, 2005.
15. National Cattlemen’s Beef Association. Beef Facts: Stearic Acid – A Unique Saturated Fat. Centennial, CO: National Cattlemen’s Beef Association, 2007.
16. Huth, P.J. Do ruminant trans fatty acids impact coronary heart disease risk? Lipid Technol. 19(3): 59-62, 2007.
17. National Cattlemen’s Beef Association. Beef Facts: Conjugated Linoleic Acid and Dietary Beef – an Update. Centennial, CO: National Cattlemen’s Beef Association, 2007.
18. Kritchevsky, D., Tepper, S.A., Wright, S., et al. Conjugated linoleic acid isomer effects in atherosclerosis: growth and regression of lesions. Lipids 39: 611-616, 2004.
19. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C., National Academy Press, 1998.
20. McKay, D.L., Perrone, G., Rasmussen, H., et al. Multivitamin/mineral supplementation improves plasma B-vitamin status and homocysteine concentration in healthy older adults consuming a folate-fortified diet. J. Nutr. 130: 3090-3096, 2000.
21. Mann, N.J., Li, D., Sinclair, A.J., et al. The effect of diet on plasma homocysteine concentrations in healthy male subjects. Europ. J. Clin. Nutr. 53: 895-899, 1999.
22. Herrmann, W., Schorr, H., Purschwitz, K., et al. Total homocysteine, vitamin B12, and total antioxidant status in vegetarians. Clin. Chem. 47: 1094-1101, 2001.
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23. Gao, X., Yao, M., McCrory, M.A., et al. Dietary pattern is associated with homocysteine and B vitamin status in an urban Chinese population. J. Nutr. 133: 3636-3642, 2003.
24. Koebnick, C., Hoffmann, E., Dagnelie, P.C., et al. Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women. J. Nutr. 134: 3319-3326, 2004.
25. Haulrik, N., Toubro, S., Dyerberg, J., et al. Effect of protein and methionine intakes on plasma homocysteine concentrations: a 6-mo randomized controlled trial in overweight subjects. Am. J. Clin. Nutr. 76: 1202-1206, 2002.
26. Flores-Mateo, G., Navas-Acien, A., Pastor-Barriuso, R., et al. Selenium and coronary heart disease: a meta-analysis. Am. J. Clin. Nutr. 84: 762-773, 2006.
27. Sullivan, J.L. Iron versus cholesterol – perspectives on the iron and heart disease debate. J. Clin. Epidemiol. 49: 1345-1352, 1996.
28. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, D.C.: National Academy Press, 2001.
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31. Wood, R.J. The iron-heart disease connection: is it dead or just hiding? Ageing Res. Rev. 3: 355-367, 2004.
32. Hodgson, J.M., Ward, N.C., Burke, V., et al. Increased lean red meat intake does not elevate markers of oxidative stress and inflammation in humans. J. Nutr. 137: 363-367, 2007.
33. Whiteman, D., Muir, J., Jones, L., et al. Dietary questions as determinants of mortality: the OXCHECK experience. Public Health Nutr. 2: 477-487, 1999.
34. Hu, F.B., Stampfer, M.J., Manson, J.E., et al. Dietary saturated fats and their food sources in relation to the risk of coronary heart disease in women. Am. J. Clin. Nutr. 70: 1001-1008, 1999.
35. Scott, L.W., Kimball, K.T., Wittels, E.H., et al. Effects of a lean beef diet and of a chicken and fish diet on lipoprotein profiles. Nutr. Metab. Cardiovasc. Dis. 1: 25-30, 1991.
36. Scott, L.W., Dunn, J.K., Pownall, H.J., et al. Effects of beef and chicken consumption on plasma lipid levels in hypercholesterolemic men. Arch. Intern. Med. 154: 1261-1267, 1994.
37. Beauchesne-Rondeau, E., Gascon, A., Bergeron, J., et al. Plasma lipids and lipoproteins in hypercholesterolemic men fed a lipid-lowering diet containing lean beef, lean fish, or poultry. Am. J. Clin. Nutr. 77: 587-593, 2003.
38. Melanson, K., Gootman, J., Myrdal, A., et al. Weight loss and total lipid profile changes in overweight women consuming beef or chicken as the primary protein source. Nutrition 19: 409-414, 2003.
