A grilling analysis
With the July 4th holiday come parades, marching bands, fireworksand the near-obligatory backyard grillfest.
"More than 200 million Americans, three-quarters of the population, will attend or host a barbecue this weekend," says Brian Halweil of the Worldwatch Institute, an environmental think tank in Washington, D.C. However, he notes, "few will reflect on the health and environmental effects of meat consumption."
In a research paper released this week, he does just that. And his findings are discomforting at best.
Over the past half century, world meat production has nearly quintupledrising from 44 million to 211 million tons. Even after accounting for the growth in population, this reflects a more than doubling in per capita meat consumptionto about 80 pounds.
Producing this meat comes at a high price. Roughly one-third of the worlds grain, some 670 million tons, goes to feed livestock, including poultry. Diverting even 10 percent of this feed back to direct human consumption would free up 67 million tons of grainenough to meet the dietary needs of 225 million people, Halweil argues. This is roughly equivalent to the projected growth in world population over the next 3 years.
Even "if each American reduced his or her meat consumption by only 5 percent, roughly equivalent to eating one less dish of meat each week, 7.5 million tons of grain would be saved," he calculates. This is an amount sufficient to feed 25 million persons, or about the same number that now go hungry in the United States.
Such a small change in eating patterns can have such a dramatic impact because the United States is among those nations possessing an exceptionally carnivorous appetite. While one-quarter of the worlds population lives in the United States and China, consumers in these two countries now scarf up 35 percent of the worlds beef, more than half of its chicken, and 65 percent of its pork.
A diet based on livestock has high costs in environmental terms that go beyond the caloric wastes related to grain use as animal feed. Animals that eat large amounts of grain generate equally large volumes of wastes. In the United States, Halweil reports, the volume "generated by livestock is 130 times that produced by humans." Indeed, he cites one hog farm being developed in Utah that will ultimately span 50,000 acres and "produce more waste than the city of Los Angeles."
These animal-waste estimates refer only to what comes out in liquid or solid form. Livestock also generate huge quantities of methane, a potent greenhouse gas. Altogether, livestock operations account for one-quarter of the methane produced by human activities globally, Halweil finds.
In many areas, the wastes generated by industrial-size livestock operations have led to serious environmental problems and spurred new regulatory initiatives. Among the more recent examples are the hog and chicken wastes being blamed for fueling the explosive growth of toxic algae, such as Pfisteria, along the Eastern Seaboard.
"As the current scale of meat production wreaks havoc on the environment," Halweil observes, "the current scale of meat consumption threatens human health."
His argument focuses on the multitude of studies indicating that diets loaded with excess animal proteinespecially red meat and the saturated fat that it brings to the dinner tablecan foster a large number of chronic diseases. These include cancer, heart disease, and diabetes.
Coping with the impacts of these diseases takes a heavy economic toll. Halweil cites published estimates that "excessive meat consumption is responsible for between $60 billion and $120 billion in health care costs each year in the United States alone." Last year, for comparison, "domestic cash receipts for the meat industry totaled roughly $100 billion," he notes.
His report, however, ignores the indirect health impacts of our hungering for meatinjuries borne by someone other than the diner. They include any occupational hazards encountered by butchers, meat cutters, and persons who package that meat at the supermarket.
A study reported in the April 15 American Journal of Epidemiology found that people employed in meat cutting and packaging run a greatly elevated risk of leukemia and lymphoma. Though no one has indicted specific carcinogenic agents, one suspicion is that at least some of these cases stem from exposure to cancer-causing viruses in the animal tissues.
Catherine Metayer and her colleagues at the Tulane University School of Public Health and Tropical Medicine gleaned their data from death records for roughly 29,000 former members of a meat-cutters union in Baltimore. Between 1949 and 1980, 56 deaths from leukemias and lymphomas were noted. Cancer risk factors of these men were compared to those in a similar number of union members who died of lung cancer and in a third groupfamily members or close friends of meat cutters, all of whom worked in other occupations.
Overall, the study found that butchers were five times as likely to develop blood and lymph-system cancers as were those employed in other areas. However, there appeared to be sharp differences in risk, depending on where the man worked. Among those employed in slaughtering houses, for example, the leukemia/lymphoma risk was only about three times as high as in people employed elsewhere. For supermarket meat cutters, however, the study found an 18-fold excess of multiple myeloma, a type of leukemia. And supermarket workers who mainly wrapped meat appeared to experience nearly four times the rate of lymphomas and leukemias as did those who worked outside the meaty environment.
The fishy alternative
Feeling righteous because youre grilling tuna or salmon steaks on Independence Day? Well, take note: Outside Alaska, most wild salmon are overfishedsome to the point that certain of their populations are endangered. Among tunas, only skipjack stocks are not overfished, according to an analysis by Carl Safina, director of the Audubon Societys Living Oceans Program.
Collectively, the worlds fish harvest has climbed to 120 million tons annually, or six times the catch in 1950. As a result, almost one-third of the worlds most popular oceanic fisheries are now overexploited. Regionally, some stocks have crashed to the point of virtual extinction.
Rep. Jim Saxton (R-N.J.) attributes part of this problemat least as it affects fisheries in U.S. watersto the contradictory mission of the National Marine Fisheries Service (NMFS). When Congress created the agency 28 years ago, it charged it with both promoting the harvesting of fish, especially underutilized stocks, and regulating catches to sustain stocks at a healthy size.
While NMFS has proven quite effective at promoting new fisheries, it has had a much harder time ensuring that rates of harvests dont become excessive. As Saxton explained at a news conference last week, "NMFS does not have a single goal, it has two. And they conflict."
In other words, he says, the agency has encouraged fleets to haul in more fish and consumers to bring home more seafood. Today, he says, a new message has to go out: Both fishers and diners need to become more discriminating in what they take home from the sea. Where fisheries have collapsed or are on the verge of doing so, fleets must go elsewhere until the stocks have recovered.
Observes Mike Nussman, vice president of the American Sportfishing Association, "I personally believe that if consumers of seafood knew the status of stocks, theyd probably think twice before they bought some of them." He thinks they would purposefully select fish from better managed stocksand even pay a premium for them.
"Our first challenge, then, is to make sure that the 250-million-plus Americans understand what is happening to their public resource," contends David Wilmot, executive director of the Ocean Wildlife Campaign, which is based in Washington, D.C. For instance, the large and long-lived fish that tend to frequent open waterssuch as swordfish, tunas, billfish, and sharksare among those currently suffering some of the heaviest exploitation.
Though adult Atlantic swordfish used to grow to more than 1,000 pounds, the average one landed in 1995 weighed in at just 90 pounds, according to a February report by the National Coalition for Marine Conservation. At that size, it says, the fish is immatureand "two years shy of its first chance to reproduce." Owing to overfishing, the adult breeding population of this fish has fallen by 66 percent over the past decade.
Which fish deserve a break?
Concerned about the swordfish's precarious status, the Natural Resources Defense Council and SeaWeb, two environmental groups, launched a year-long campaign in January called "Give a Swordfish a Break." At a kick-off news briefing in New York City, local chefs explained why they were willing to swear off serving the popular entree this year.
This past Wednesday, SeaWeb announced that the program has proven an overwhelming success, with effects "reverberating from backyard barbecues to the White House." More than 200 chefs have stopped serving swordfish, as have several cruise ship lines, including Royal Caribbean, Princess, and Celebrity. Even Bon Appetit magazine has volunteered to ban swordfish recipes from its pages.
More importantly, SeaWeb reports, the seafood industry acknowledges the campaign has diminished demand for the fish.
"The campaign is not a boycott but rather a time out designed to raise public awareness about the plight of the North Atlantic swordfish and to pressure the federal government to create a meaningful recovery plan for this severely depleted fish," says Vikki Spruill, SeaWebs executive director.
But which other fish deserve a similar break?
Safina has compiled a table that gives consumers some guidelines. Published in the June Audubon, it not only describes the status of marine populations and how well their stocks are being managed but also highlights any environmental concerns raised by the way particular groups are harvested.
It indicates that seafood lovers can still eat striped bass, mahimahi (dolphinfish), mackerel, squid, and most crabs without guilt. Among those that he recommends keeping off the serving platter, however, are sharks, swordfish, orange roughy, groupers, Atlantic groundfish (such as cod, haddock, pollack, scrod, yellowtail flounder, and monkfish), scallops, salmon, Pacific rockfish, and red snapper. Farm-raised salmon and shrimp create their own environmental problems.
If youre in the supermarket and dont have the chart with you, Safina notes that consumers can turn to price as an alternative rule of thumb. "Overfished fish usually cost more," he explains, because there are fewer to go around and catching each ton takes more time and effort.
Beyond grilled veggies
As a vegetarian, Halweil believes that "a meatless Fourth of July would be wonderful." Indeed, he recalls, "some of my fondest memories of barbecues involve roasting up ears of corn and potatoes." For something a little different, he suggests that "sliced eggplant with a little olive oil roasts up very nicely on the grill. And vegetable kebabs are great."
Though he would like to see people in the United States adopt a largely vegetarian diet, he concedes that most are unlikely to forswear meat, at least any time soon. So hed be pleased as fruit punch to see most revelers just reduce the quantity of meat they throw on the grill this Independence Day. "Its just one day, and your body may actually appreciate it."
Safina would like to see individuals go beyond altering their diet. Rather than congratulating themselves for eschewing depleted fish or meat that is produced using excess resources, he says, "Make your values extend beyond your own individual behavior."
By politicizing the swordfish issue, for instanceturning the concerns of many individuals into a coordinated campaign"were really affecting markets by cutting tons and tons of swordfish orders," he says.
"The bottom line," Halweil told Science News Online, "is that people must do something. For those concerned about the environment, reducing meat and fish consumption should be as fundamental as reducing car use or being a conscientious recycler. And for those concerned about their health, reducing meat consumption is as essential as quitting smoking or proper exercise."
Halweil, B. 1998. On July 4, United States leads world meat stampede. Worldwatch Institute: Washington, D.C.
Maharaj, V. 1998. The economic importance of marine recreational fishing in the United States: Case studiesStriped bass and bluefin tuna. American Sportfishing Association report (June 24). Available online (www.asafishing.org).
McGinn, A.P. 1998. Rocking the boat: Conserving fisheries and protecting jobs. Report #142 (June 20). Washington D.C.: Worldwatch Institute.
Metayer, C., E.S. Johnson, and J.C. Rice. 1998. Nested case-control study of tumors of the hemopoietic and lymphatic systems among workers in the meat industry. American Journal of Epidemiology 147(April 15):727.
National Coalition for Marine Conservation. 1998. Ocean roulette: Conserving swordfish, sharks and other threatened pelagic fish in longline-infested waters (February).
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This week's Food for Thought has been prepared by Janet Raloff, senior editor of Science News.
Food for Thought Archives
copyright 1998 ScienceService