By Stephen B. Smith, Ph.D.
Regents Professor, Department of Animal Science
The internet is awash in websites proclaiming the nutritional benefits of ground beef from grass-fed cattle. However, researchers in the Department of Animal Science at Texas A&M University have published the only two research studies that actually compared the effects of ground beef from grass-fed cattle and traditional, grain-fed cattle on risk factors for cardiovascular disease (CVD) and type II diabetes in men. Was ground beef from grass-fed beef actually more healthful?
Americans consume approximately 40 percent of their total beef intake as ground beef, which is much higher in total fat than most intact cuts of beef. In fact, ground beef is one of the most important sources of the healthful monounsaturated fatty acid, oleic acid in the diet (the importance of this is discussed below). Ground beef from grass-fed cattle naturally contains more omega-3 fatty acids than from grain-fed cattle (three times as much) but is higher in saturated and trans-fat. At the other end of the spectrum is premium ground beef, such as from conventionally produced Certified Angus Beef or from cattle with Japanese genetics (available as Wagyu or Akaushi ground beef). Ground beef from these cattle is very high in oleic acid and is also much lower in saturated and trans-fat than ground beef from grass-fed cattle.
The information listed below is based on research conducted at Texas A&M University, which compared the fatty acid composition of ground beef from grass-fed and grain-fed cattle. Ground beef from grass-fed and grain-fed cattle that contains approximately 10 to 15 percent total fat (85 to 90 percent lean) is available in retail stores, so the values listed below are for a 4-ounce ground beef patty (quarter pounder) that contains 85 percent lean (15 percent fat).
The most abundant omega-3 fatty acid in our foods is α-linolenic acid (ALA), which is one of the two essential fatty acids that must be obtained from the diet (the other is linoleic acid, which is an omega-6 fatty acid). ALA is found in flax seed and walnuts, but Americans obtain most of their ALA from canola oil. Although the scientific studies are not conclusive, ALA may slow the rate of growth of cancer cells and may also reduce risk factors for CVD. The Daily Reference Intake (DRI) of ALA is 1.1 grams per day for women and 1.6 grams per day for men. So, a quarter pounder ground beef patty from grass-fed cattle contains 0.055 of the 1.1 grams ALA required by women and 0.055 of the 1.6 grams ALA required by men. In other words, that ground beef patty from cattle fed native Texas pastures contains only 5 percent of the DRI for ALA for women and just over 3 percent of the DRI for ALA for men. Yes, grass-fed ground beef contributes to the omega-3 fatty acids in our diets, but can it be considered a significant source of ALA?
For comparison, a tablespoon of canola oil (approximately 14 grams of canola oil) contains 1.4 g of ALA. This is more than the DRI for women and almost as much as the DRI for men. That same tablespoon of canola oil also contains 8.4 grams of oleic acid, which is similar to the amount of oleic acid in olive oil. Researchers have known for decades that oleic acid has positive health benefits, such as reducing LDL-cholesterol (the bad cholesterol) and perhaps increasing HDL-cholesterol (the good cholesterol). The World Health Organization has recommended that intake of oleic acid should be 15 to 30 percent of daily energy intake. For women, that would be equal to 25 – 50 grams of oleic per day, whereas for men, that would be equal to 40 – 80 grams of oleic per day. Research in the Department of Animal Science has shown that men consume about 20 grams of oleic acid per day, and women consume about 12 grams of oleic acid per day, but this can be nearly doubled by consuming ground beef high in oleic acid, such as ground beef from grain-fed cattle or cattle with Japanese genetics.
|Omega-3 fatty acids||Oleic acid||Total saturated and trans-fat|
|Ground beef from grass-fed (grazing on native Texas pasture)||0.055 grams||6.3 grams||9.8 grams|
|Ground beef from grain-fed cattle (fed a feedlot diet containing primarily corn and milo)||0.020 grams||8.3 grams||8.2 grams|
Grass feeding definitely does not increase the amount of oleic acid in beef. The quarter pound ground beef patty from grain-fed cattle contains over 2 grams more oleic acid than ground beef from grass-fed cattle. In fact, the grain-fed ground beef patty contains nearly the same amount of oleic acid as the tablespoon of canola oil. Also, ground beef from grass-fed cattle has 2 grams more saturated fat plus trans-fat than the patty from grain-fed cattle.
So, which is better, more omega-3 fatty acids (grass-fed) or more oleic acid with less saturated/trans-fats (grain-fed)? Studies in the Department of Animal Science demonstrated the effects of ground beef from grass-fed and grain-fed cattle. Men consumed both types of ground beef for five weeks in randomized crossover trials. In older, mildly hypercholesterolemic men, ground beef from grass-fed cattle decreased HDL-cholesterol. In men with normal cholesterol levels, only ground beef from grain-fed cattle increased HDL-cholesterol. Neither ground beef type increased LDL-cholesterol in men. Research by the Department of Animal Science similarly demonstrated that consuming ground beef does not affect LDL-cholesterol in postmenopausal women.
In men, plasma insulin was decreased by ground beef from both grass-fed and grain-fed cattle, indicating that ground beef in general reduces this important risk factor for type II diabetes. Thus, neither type of ground beef had negative effects on risk factors for CVD or type II diabetes, but the ground beef from the grain-fed cattle provided more positive health benefits by increasing HDL-cholesterol.
What about the cholesterol content of ground beef? Many websites claim that beef from grass-fed cattle is lower in cholesterol than beef from conventionally raised cattle. An excellent study from Texas Tech University demonstrated that there is no difference in cholesterol in ground beef from grass-fed and grain-fed cattle if the fat content is similar. Early research conducted at Texas A&M University demonstrated that the cholesterol in beef and beef products is stored in both the lean and the fat within the meat. If you trim all of the fat from beef (including the marbling), there will be about 45 milligrams of cholesterol in a 4 ounce serving of beef. For every 1 percent increase in total fat content there is a 1-milligram increase in cholesterol. So, ground beef that is 95 percent lean (5 percent fat) contains about 50 milligrams of cholesterol and ground beef that is 85 percent lean (15 percent fat) contains 60 milligrams of cholesterol. This is as true for beef from grass-fed beef as it is for beef from grain-fed cattle.
So, at this point, there is no scientific evidence to support the claims that ground beef from grass-fed cattle is a healthier alternative to ground beef from conventionally raised, grain-fed cattle.
S.B. Smith is a Texas A&M AgriLife Research meat scientist in the Department of Animal Science at Texas A&M University and has published more than 180 scientific articles, most of which describe the nutritional quality of pork and beef.
For more information regarding news from the Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, please contact Courtney Coufal at email@example.com or (979) 845-1542.