Monday, February 9, 2015

Meat, Health and the Environment

A young person I know has recently become a vegetarian and my step sister and her spouse have become vegans. So, I have been thinking about many of the aspects of food sustainability, and the many different styles of being a “vegetarian.” These days a diet limited to only plant based food is called veganism. Vegetarians can include dairy products, eggs and seafood. The most basic definition of vegetarian is someone who eats anything but land based meat.

According to Dr. Vaclav Smil formerly of the University of Manitoba and author of Should We Eat Meat? the various permutations of vegetarianism represent less than 4% of all western societies and the long-term adherence to a vegetarian diet is less than 1%. (My step sister supplements her vegan at home diet with the occasional hamburger which turns out to be probably an excellent diet.) The reasons someone becomes a vegetarian vary from moral to those who become vegetarians for more pragmatic reasons to lose weight, reduce blood pressure, cholesterol or reduce cancer risk.

According to Dr. Smil’s book several large scale national studies into diet, disease and longevity found that Japan and Europe’s three countries with the longest life expectancy all have diets with substantial quantities of meat and/or dairy products. A large scale British study matching vegetarians with “moderate” omnivores and a European investigation found no measurable difference in mortality from circulatory diseases and all causes between meat eaters and vegetarians.

However, according to work done by Anthony Worsley and Grace Skrzpiec in the past 20 years, one of the largest groups of vegetarians are teenagers, specifically upper middle class teenage girls. Their research found that “teenage vegetarianism is primarily a female phenomenon, ranging in prevalence, according to definition, from 8 to 37% of women and 1 to 12% of men. Support for vegetarian practices was high especially from mothers (63%) and classmates (46%).”

The findings of the research were that teenage vegetarianism is largely a female phenomenon characterized by meat avoidance, concern for the environment, animal welfare, gender equity, weight-loss behaviors and high concern with body appearance. The scientists found a strong association between adolescent vegetarianism and extreme weight-loss behaviors, which may be according to the authors indicative of eating disorders.

Homo sapiens are an omnivore with a high degree of natural preference for meat consumption. According to Dr. Vaclav Smil only later did increasing density of populations create the need to abandon hunting and gathering and progressively increase permanent settlements with crop farming. The agrarian life was accompanied by cultural adaptions of meat restrictions and taboos turned meat into a relative rare foodstuff for the vast majority of the population in traditional agricultural societies. The return to more frequent meat eating has been a transition in affluent economies.

Meat is one of the best sources of dietary iron because it supplies the mineral as heme iron that is easily absorbed in the small intestine and also helps to absorb the non-heme iron present in plants like spinach. Even modest meat consumption helps to prevent iron deficiency anemia. While men and children only require 8-11 mg/day of iron, pre-menopausal women require 18 mg/day and pregnant women require 27 mg/day of iron. (The groups most likely to be vegetarian needs the most iron- ironic?) Meat followed by dairy products is the single largest source of high quality protein, essential fatty acids and micro nutrients. Meat is also rich in B6, B12 and niacin as well as zinc. A zinc deficiency slows growth, increases infection rates, skin lesions and impairs wound healing. In addition an average weight adult needs 50 grams of protein a day and children must have adequate energy, protein and nutrient consumption to avoid stunting and deficiencies that could cause serious mental and cardiac problems in growing and developing Homo sapiens. The “typical” western diet reportedly contains between 85-95 grams of meat a day, so we could cut back on meat and work to optimize our diets for our tastes, and our bodies. People are different.

According to an interdisciplinary report prepared by the Food and Agriculture Organization of the United Nations, FAO, 26% of the earth’s surface is used as grazing land, 33% of all arable land is utilized to grow feed for animals, as much as 18% of greenhouse gas emissions come from raising primarily beef livestock, and it takes 1,800 gallons of water to produce a pound of beef. According to a recent article in New Scientist magazine “as much as 32% of greenhouse gas emissions come from rearing livestock.” I could not track down the source of that assertion. However, becoming a vegetarian is not necessarily the greenest choice.

According to Dr. Vaclav Smil there is lots of land used as pastureland around the world that cannot be used to grow crops. If this land is grazed properly it can be grazed sustainably forever. The grasses in the pasture cannot be digested by man, but cows and sheep can. This is the philosophy of a nearby farm, Polyface, operated by three generations of the Salatin family. The Salatin family built their farm by first rehabilitating the land. They planted trees, built compost piles, dug ponds, and moved cows daily with portable electric fencing, to create what they call a “perennial prairie polyculture.” Grazing animals in rotation contributes to the biological diversity. The pastured livestock and poultry at Polyface farm are moved frequently to new areas of the farm to allow the landscape healing and nutrient rebuilding. Dr. Vaclav Smil says that if we used only used sustainable grazing and fed livestock on crop residues we could still raise about two-thirds of the meat we do now, and we could extend the meat using plant protein. Still, his suggestions are processed and created food. There may simply be a limit on how much food our earth can produce sustainably.

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