Wednesday, April 1, 2009

To Make a Prairie: Part IV, Health Benefits of Grass-fed

Anyone who reads Grass,Sky, Song or this blog will see that I am suggesting that one of the things we can do for grassland birds is buy our meat, eggs, and dairy products from producers who feed their animals grass instead of grain. In the first two postings on this topic (March 15 and March 25) I described the environmental benefits of raising animals on grass alone--namely, if the dairy, eggs, and meat protein we consume come from animals that eat nothing but grass (and in the case of poultry, insects), there will be more support for producers to keep more land in grass, native and non-native, and less stimulus for growing grain to feed animals in feedlots and intensive livestock operations. If we could convert even a small percentage of the animal protein we consume in North America from grain-fed to grass-fed, there would be a correspondent increase in grassed land. That in turn can provide better habitat for birds that use grass to nest and forage and it helps reduce the amount of carbon that agriculture releases into the atmosphere.

But that is only half of the story. The other good news about grass-based agriculture is that it is much better for human health. I keep coming across new information on this topic, but one of the best explanations of how grain-fed animal produce has made us unhealthy appears in David Servan-Schreiber's book, Anticancer: A New Way of Life. On pages 65 to 68 of this international bestseller, Servan-Schreiber, an M.D. and cancer survivor, refers to work done by a team of French researchers who explain something he calls "the American paradox." The paradox was that while Americans' overall consumption of fats and total calories declined between 1976 and 2000, obesity increased dramatically. Even in children under one, the mass of fatty tissue doubled during a 20 year period. We typically blame lack of exercise and fast food for obesity in North America, but as the head of the French researchers, Girard Ailhaud, said, for infants "you can't blame McDonald's, snacking, TV, and lack of physical exercise." These children were still getting the same quantity of milk as infants but the quality had changed dramatically. Something was out of balance. Servan-Schreiber explains:

"Starting in the fifties, the demand for milk products and beef went up so much that farmers had to look for shortcuts. . . and reduce the grazing area needed to feed a 750-kilogram (1,600-pound) cow. Pastures were thus abandoned and replaced by battery farming. Corn, soy, and wheat, which have become the principal diet for cattle, contain practically no omega-3 fatty acids. To the contrary, these food sources are rich in omega-6s. Omega-3 and omega-6 fatty acids are called "essential" because the human body cannot make them. As a result, the quantity of omega-3s and omega-6s in our bodies stems directly from the content of the food we eat. In turn, the amounts of omega-3 and omega-6 fatty acids in our food depend on what the cows and chickens we eat have consumed in their feed. If they eat grass, then the meat, milk, and eggs they provide are perfectly balanced in omega-3s and omega-6s."

He goes on to explain the healthy push-pull tension between these two fatty acids when they are in balance in our bodies, and says that when the balance favours omega-6s--as it does in most people eating meat, dairy, and eggs from feedlot and industrial-farmed livestock--then we have trouble keeping the fat off and become more susceptible to cancer, particularly breast cancer.

Servan-Schreiber is merely one doctor making the case for pasture and grass-fed animals in our agriculture. Many other scientists are seeing the connection between grass-based agriculture and a healthy balance of fatty acids. In 2006, the Union of Concerned Scientists undertook the first comprehensive comparison of fat levels in beef and dairy products from conventionally raised and pasture-raised animals. Their report, Greener Pastures: How Grass-fed Beef and Milk Contribute to Healthy Eating, presents the results of this analysis.

1 comment:

  1. Hélène Tremblay-BoykoApril 13, 2009 at 4:38 PM

    Further to the health benefits to humans, I have found, in Michael Pollan's "The Omnivore's Dilemma", that it appears that we have, in the process of feeding grain to cattle, changed their gut acidity to match our own. Grass fed cattle have a neutral pH in their gut and any intestinal bacteria from the grass eaters is killed off in the high acid of our stomachs. Unfortunately, "a relatively new strain of the common intestinal bacteria Escherichia coli O157:H7 (which had never been seen before 1980)thrives in feedlot cattle. Ingesting as few as ten of these microbes can cause a fatal infection; they produce a toxin that destroys human kidneys.
    Most of the microbes that reside in the gut of a cow and find their way into our food get killed off by the strong acids in our stomachs, since they evolved to live in the neutral pH environment of the rumen. But the rumen of a corn-fed feedlot steer is nearly as acidic as our own stomachs, and in this new, man-made environment new acid-resistant strains of E. coli have evolved."


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