Steak - Mark Schatzker [101]
Does eating grass-fed meat actually reduce your cholesterol? Will eating grain-fed steak give you—or, worse, me—a heart attack? Would the hearts of all those tobacco-smoking, steak-loving Argentine men begin infarcting if their yearly 150 pounds of beef came from feedlots?
To answer that question with certainty, you would have to raise thousands of people in identical settings and circumstances and feed them identical diets, the only difference being that half would spend their lives eating feedlot beef and the others would eat only grass-fed beef. At various ages, you would measure fat, cholesterol, and plaque buildup in the arteries, body mass index, and whatever other measurable metrics come to mind. You would wait out the decades and see who died of what, and when. Finally, when the last member of the study group expired, you’d have some serious data. Good luck getting that kind of funding.
In the real world, there are too many variables to make such comparisons easy. Argentines drink a lot of red wine. Many of their cars don’t have catalytic converters and spew out noxious exhaust, and their health care system leaves much to be desired. Americans watch more TV and drink more soft drinks than Argentines. Americans also eat more feedlot beef than Argentines.
Only a single study, so far as I am aware, has ever attempted to compare the effects of feedlot beef with those of grass-fed beef. In 2006, the Cardiovascular Institute of Buenos Aires teamed up with a steak-friendly outfit called the Argentine Beef Promotion Institute and put forty-eight healthy people—twenty-four men and twenty-four women—on the same diet. For twenty-eight days—and this could only ever happen in Argentina—the men ate 200 grams of steak every day, and the women ate 150 grams. At the end of the twenty-eight days, there was a recess of twenty-one days, and then another twenty-eight-day cycle would commence.
There were four such cycles, all told, and during each one the subjects ate a different type of beef: grass-fed, grain-fed, or mixed (which means that the cows ate some grass, and a little grain, too). During the fourth cycle, one type of beef was repeated. At the end of each cycle, the subjects were measured, weighed, prodded, and blood was drawn from their veins and analyzed.
The results were what you might expect: when people ate grass-fed beef, their blood looked more like that grass-fed beef, containing more vitamin E and beta-carotene as well as more omega-3 fatty acids. HDL cholesterol (good cholesterol) was up slightly after a month on pasture beef, while LDL (the bad stuff) was down. The study did not yield the kind of earthshaking, eye-popping data that would have made grass-fed beef an instant nutritional panacea, as happened with oat bran in the late 1980s. The differences in the numbers were actually slight. That was most likely the case because the subjects ate lean beef—more fat may have resulted in more compelling data—and because twenty-eight days is not long enough for a diet to show dramatic effects. The data indicate a trend of the sort that would make a scientist say, Hey, there’s something going on here. Let’s do another study.
It is also worth noting that after the four cycles were completed, the forty-eight participants had lost, on average, two pounds and increased their muscle mass. A pamphlet published by the Argentine Beef Promotion Institute announced, “It may be assured that consuming beef once a