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The meat controversy—biology, ecology and ethics

First lets look at meat eating from a biological point of view. Humans are omnivores.  From the length and architecture of our digestive tracts to our nutritional requirements we maintain the best health on a diet that includes both animal and plant foods.  In fact our hunter-gatherer ancestors ate far more meat and fat as a proportion of their diet than we do today.  With the advent of agriculture and the consequent consumption of a grain rather than a meat based diet our ancestors lost and inch or two of height and their skeletons became less robust.  There was a slight rebound in bone size with the domestication of animals.1

Protein from meat, milk and eggs is termed complete protein because it contains all of the amino acids in the same balance that they are found in the human body.  Therefore they are efficiently absorbed and utilized, unlike plant proteins, which are universally low in one or more amino acids and are used much less efficiently. Looking at specific nutrients, vitamin B12 is found only in animal protein.  There are no vegetable sources.  B12 deficiency leads to pernicious anemia with resultant permanent neurological damage.  Vitamin A is also found only in animal foods.  Beta carotene is found in plant foods but is very inefficiently converted to vitamin A in the body.  Most minerals are found in much higher levels in animal foods and are more available because they are not blocked from absorption by phytates as they are in most plant sources.

Much ado was generated in the media last year when a study was published in the Archives of Internal Medicine that concluded, “red and processed meat intakes were associated with modest increases in total mortality, cancer mortality, and cardiovascular disease mortality.”2 In this study, which was a large epidemiological study of about 500,000 AARP members aged 50-71, participants filled out a food frequency questionnaire asking about their food intake for the previous year.  From personal experience I know how difficult these questionnaires are to answer accurately, and I am well versed in nutrition and conscious of what I eat!  So to begin with the data are suspect. In addition, it is the nature of an epidemiological study to find correlations or associations between variables, but in no way can it identify causation.  Interestingly, the researchers found that meat eaters were more likely to smoke, took in more calories, were heavier, had a lower educational level, were less likely to exercise, and ate fewer fruits and vegetables.  Might these be more important associations of their higher mortality?  But what I find totally missing from this study is any analysis of the processed carbohydrate intake of these subjects.  Might it be that, since ‘everyone knows’ (given current misguided dietary advice) meat is unhealthy, the more health-conscious subjects were eating less meat but were also engaging in other positive health behaviors?  The people eating more meat were probably also eating more white buns, sugar, soda, and French fries (hydrogenated oil) and other unhealthy foods not accounted for in this study.  The authors do admit that the associations of meat eating with disease were modest.  Had they accounted for processed carbohydrates and trans fats in their analyses I postulate that the associations would have disappeared!

Another problem with epidemiological studies is that they compare the diets that people actually say they eat, and the vast majority of American food intake is sub-optimal. Virtually all of the people in this survey were eating CAFO (concentrated animal feeding operation) meats, since this type of meat is universally sold in grocery stores. How beef, pork, chicken, and lamb are raised is very important for nutritional quality.  CAFO meat is higher in omega 6 fatty acids and lower in omega 3 fatty acids and has more obnoxious chemicals stored in its fat than meat raised organically on pasture. But grass fed and naturally raised meat can’t be assessed in epidemiological studies because too few people are consuming it.

From an ecological perspective the raising of meat can be a sustainable operation that enhances rather than damages the environment.  Cattle, pigs, chickens and lambs are meant to roam free outdoors and eat a variety of foods.  Cattle and lambs do best on grass, pigs eat a variety of foods and chickens are meant to eat grass and insects as well as grain.  When sustainably raised the animal waste fertilizes the soil and enhances the grass pastures that enrich the animals.  Everything is used and reused.  Marginal land that is not suitable for plowing will often grow lush grass and sustain grazing animals.

Detractors of meat eating purport that consuming mostly plants is better for the environment.  They may cite the current industrial model for raising meat, in which corn and soy are fed to cattle in order to fatten them faster. Grass is the natural diet for cattle, not grain.  They may fatten fast on grains but they also experience health problems.  These illnesses along with the crowding of the animals necessitate frequent antibiotic and pesticide treatment, and often result in contaminated meat.  The waste matter that is generated from the unnatural diet and crowded conditions is not recycled and creates massive pollution problems. But in growing the grains that sustain a plant-based diet, our current industrial agriculture system, which uses mega farms growing monoculture crops of genetically modified grains, depends heavily on petroleum-based fertilizers and pesticides.  In the process of growing these grains countless native species of birds, small mammals, reptiles, amphibians, and beneficial insects and worms are exterminated and many are on the brink of extinction.  The consumption of these crops of soy, wheat and corn, mainstays of a plant-based diet, therefore probably does more environmental damage than consuming animals raised on their natural foods.

Finally, the ethics of eating meat is a non-argument.  That’s the way life works.  Eat or be eaten.  We humans tend to think that only mammals and maybe birds are important, but when you consider all of the small animals and native plants killed or displaced by our current system of growing grains you realized that to live is to eat and to eat something has to die.

What is the answer? Eat meat for robust health. If possible find meats and poultry raised humanely on sustainable farms. If enough of us demand sustainably raised meats the food/agriculture industry will eventually get the idea.

1Cohen, M.C. 1989. Health & the Rise of Civilization. Yale Univ. Press, New Haven, CT. 285pp.

2Sinha, R, AJ Cross,; BI Graubard, MF Leitzmann, A Schatzkin 2009. Meat Intake and Mortality: A Prospective Study of Over Half a Million People. Arch Intern Med 169:562-571.

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