Well, as a matter of fact, a brief search turned up a May 2009 special issue of the *American Journal of Clinical Nutrition* that is relevant to our discussion. They may not consider all the potential implications, but at least we have something scientific to go on. I have pasted several relevant abstracts below.
Here's what I read from a couple abstracts that address the consumption issue (I haven't read the full studies yet): A vegetarian diet has a much lower use of water, energy, fertilizer, and pesticides. Except for pesticides, these items are 2-13 times higher for a non-vegetarian diet. Something similar is apparent when one examines greenhouse gas emissions (lifecycle). Cows are the highest contributor to these differences, with chickens less of a contributor. They do note that effects of legume production on gas emissions can be high too, but not as high as the cow based proteins. There was also a lot of information on health (the other 25 papers in the special issue). I haven't looked through these thoroughly. I did notice one that mentioned positive health effects of a vegetarian diet on heart disease, hypertension, diabetes, obesity, and perhaps cancer, although different types of cancers may not respond similarly and so a vegetarian diet may not lower the risk of all types of cancers. The authors noted an overall increase in life expectancy of vegetarians. Other studies indicate that in certain situations these health effects don't always hold up. Another study remarked that those people on vegan diets may be at risk for deficiencies of B-12, D, Calcium, and omega-3 fatty acids unless they take supplements or eat carefully. Iron and zinc may sometimes be a concern. Notice they did not mention a lack of certain amino acids, as has been suggested on this discussion board. There is some debate about how important it is for vegetarians to drink milk. Some say it is good, some say it not necessary and may even have certain detrimental effects. One study stated that early results suggest that soy infant formula has no negative health effects on humans up to the age of 5 (don't have data beyond that yet). Anyway, please feel free to go check it out yourselves. I hope we get more studies like this. Perhaps some ecologists might take an interest? Some among us are quite good at energy, water, and nutrient budgets. We shouldn't let the nutritionists have all the fun. Kevin Here are a few selected abstracts: Marlow, H. J., W. K. Hayes, et al. (2009). "Diet and the environment: does what you eat matter?" American Journal of Clinical Nutrition 89(5): S1699-S1703. Food demand influences agricultural production. Modern agricultural practices have resulted in polluted soil, air, and water; eroded soil; dependence on imported oil; and loss of biodiversity. The goal of this research was to compare the environmental effect of a vegetarian and nonvegetarian diet in California in terms of agricultural production inputs, including pesticides and fertilizers, water, and energy used to produce commodities. The working assumption was that a greater number and amount of inputs were associated with a greater environmental effect. The literature supported this notion. To accomplish this goal, dietary preferences were quantified with the Adventist Health Study, and California state agricultural data were collected and applied to state commodity production statistics. These data were used to calculate different dietary consumption patterns and indexes to compare the environmental effect associated with dietary preference. Results show that, for the combined differential production of 11 food items for which consumption differs among vegetarians and nonvegetarians, the nonvegetarian diet required 2.9 times more water, 2.5 times more primary energy, 13 times more fertilizer, and 1.4 times more pesticides than did the vegetarian diet. The greatest contribution to the differences came from the consumption of beef in the diet. We found that a nonvegetarian diet exacts a higher cost on the environment relative to a vegetarian diet. From an environmental perspective, what a person chooses to eat makes a difference. Am J Clin Nutr 2009; 89(suppl): 1699S-703S. Carlsson-Kanyama, A. and A. D. Gonzalez (2009). "Potential contributions of food consumption patterns to climate change." American Journal of Clinical Nutrition 89(5): S1704-S1709. Anthropogenic warming is caused mainly by emissions of greenhouse gases (GHGs), such as carbon dioxide, methane, and nitrous oxide, with agriculture as a main contributor for the latter 2 gases. Other parts of the food system contribute carbon dioxide emissions that emanate from the use of fossil fuels in transportation, processing, retailing, storage, and preparation. Food items differ substantially when GHG emissions are calculated from farm to table. A recent study of approximate to 20 items sold in Sweden showed a span of 0.4 to 30 kg CO2 equivalents/kg edible product. For protein-rich food, such as legumes, meat, fish, cheese, and eggs, the difference is a factor of 30 with the lowest emissions per kilogram for legumes, poultry, and eggs and the highest for beef, cheese, and pork. Large emissions for ruminants are explained mainly by methane emissions from enteric fermentation. For vegetables and fruits, emissions usually are <= 2.5 kg CO2 equivalents/kg product, even if there is a high degree of processing and substantial transportation. Products transported by plane are an exception because emissions may be as large as for certain meats. Emissions from foods rich in carbohydrates, such as potatoes, pasta, and wheat, are <1.1 kg/kg edible food. We suggest that changes in the diet toward more plant-based foods, toward meat from animals with little enteric fermentation, and toward foods processed in an energy-efficient manner offer an interesting and little explored area for mitigating climate change. Am J Clin Nutr 2009; 89(suppl): 1704S-9S. Fraser, G. E. (2009). "Vegetarian diets: what do we know of their effects on common chronic diseases?" American Journal of Clinical Nutrition 89(5): S1607-S1612. A number of studies have evaluated the health of vegetarians. Others have studied the health effects of foods that are preferred or avoided by vegetarians. The purpose of this review is to look critically at the evidence on the health effects of vegetarian diets and to seek possible explanations where results appear to conflict. There is convincing evidence that vegetarians have lower rates of coronary heart disease, largely explained by low LDL cholesterol, probable lower rates of hypertension and diabetes mellitus, and lower prevalence of obesity. Overall, their cancer rates appear to be moderately lower than others living in the same communities, and life expectancy appears to be greater. However, results for specific cancers are much less convincing and require more study. There is evidence that risk of colorectal cancer is lower in vegetarians and in those who eat less meat; however, results from British vegetarians presently disagree, and this needs explanation. It is probable that using the label "vegetarian" as a dietary category is too broad and that our understanding will be served well by dividing vegetarians into more descriptive sub-types. Although vegetarian diets are healthful and are associated with lower risk of several chronic diseases, different types of vegetarians may not experience the same effects on health. Am J Clin Nutr 2009; 89(suppl): 1607S-12S. Craig, W. J. (2009). "Health effects of vegan diets." American Journal of Clinical Nutrition 89(5): S1627-S1633. Recently, vegetarian diets have experienced an increase in popularity. A vegetarian diet is associated with many health benefits because of its higher content of fiber, folic acid, vitamins C and E, potassium, magnesium, and many phytochemicals and a fat content that is more unsaturated. Compared with other vegetarian diets, vegan diets tend to contain less saturated fat and cholesterol and more dietary fiber. Vegans tend to be thinner, have lower serum cholesterol, and lower blood pressure, reducing their risk of heart disease. However, eliminating all animal products from the diet increases the risk of certain nutritional deficiencies. Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n-3 (omega-3) fatty acids. Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed. In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals. Am J Clin Nutr 2009; 89(suppl): 1627S-33S. Eshel, G. and P. A. Martin (2009). "Geophysics and nutritional science: toward a novel, unified paradigm." American Journal of Clinical Nutrition 89(5): S1710-S1716. This article discusses a few basic geophysical processes, which collectively indicate that several nutritionally adverse elements of current Western diets also yield environmentally harmful food consumption patterns. We address oceanic dead zones, which are at the confluence of oceanography, aquatic chemistry, and agronomy and which are a clear environmental problem, and agriculture's effects on the surface heat budget. These exemplify the unknown, complex, and sometimes unexpected large-scale environmental effects of agriculture. We delineate the significant alignment in purpose between nutritional and environmental sciences. We identify red meat, and to a lesser extent the broader animal-based portion of the diet, as having the greatest environmental effect, with clear nutritional parallels. Am J Clin Nutr 2009; 89(suppl): 1710S-6S. On Sat, Sep 12, 2009 at 1:07 PM, malcolm McCallum < [email protected]> wrote: > Wayne, > You nailed it. I doubt if anyone has, but, I suspect that there would > just be different environmental problems not a reduction. It is > inevitable that every action has a reaction. > > (also, the previous post was not a response to your email, I just > posted on your thread!) > > M > > On Sat, Sep 12, 2009 at 12:37 AM, Wayne Tyson <[email protected]> wrote: > > Ecolog: > > > > What would the actual effect on species diversity of universal > > vegetarianism? Has anyone done the math? > > > > WT > > > > > > ----- Original Message ----- From: "James J. Roper" <[email protected]> > > To: <[email protected]> > > Sent: Friday, September 11, 2009 11:58 AM > > Subject: Re: [ECOLOG-L] Are ecologists the problem? > > > > > >> A well-known statistic is that there are as many domestic animals bred > >> for food for people as there are people in the world, or more. If we > >> consider a 10% conversion of food to mass of the consumer, the logic is > >> undeniable that if all ate lower on the food chain, we could use less > >> land to do it with. Also, we could do it with less energy. Another > >> detail is that more land is used to grow food for those animals than to > >> grow food for people. Just switching the land to grow food for people > >> instead of animals would mean that we could do this on much less land. > >> Habitat loss is one of the driving forces of extinctions world wide. > >> But also, pollution from high efficiency animal production is another > >> huge issue (pigs and chickens). Not to mention land degradation due to > >> grazing. > >> > >> Also well known - vegetarian diets can provide all the nutrients that > >> normal people need. > >> > >> QED - a vegetarian diet would be better for the planet (and we would > >> have much smaller problems with obesity!). > >> > >> Cheers, > >> > >> Jim > >> > >> malcolm McCallum wrote on 09-Sep-09 0:50: > >>> > >>> I tend to believe that any absolute answer that is declared an end all > >>> answer > >>> is probably not the answer. For example, I'm not convinced that > everyone > >>> jumping into a vegetarian diet is going to suddenly or even slowly > >>> save the world. > >>> Especially, considering that some of these stats are based on > unrealistic > >>> estimates. > >>> > >>> For example, suggesting that x acres of corn would feed x number of > cows > >>> and > >>> that would feed x number of people whereas the x acres of corn would > feed > >>> way > >>> more people is flawed. Humans cannot survive on a corn diet. Even if > >>> we expanded > >>> this to grains and soybeans, humans cannot survive on a corn-soybean > >>> diet. > >>> Why? because vegetables in general are low in two or three essential > >>> amino acids > >>> that humans must get in their diet. those amino acids are produced by > >>> animals > >>> and so you must ultimately get them from animals or artificially > >>> produced products. > >>> > > > > > > > -------------------------------------------------------------------------------- > > > > > > > > No virus found in this incoming message. > > Checked by AVG - www.avg.com > > Version: 8.5.409 / Virus Database: 270.13.91/2363 - Release Date: > 09/11/09 > > 09:15:00 > > > > > > -- > Malcolm L. McCallum > Associate Professor of Biology > Managing Editor, > Herpetological Conservation and Biology > Texas A&M University-Texarkana > Fall Teaching Schedule: > Vertebrate Biology - TR 10-11:40; General Ecology - MW 1-2:40pm; > Forensic Science - W 6-9:40pm > Office Hourse- TBA > > 1880's: "There's lots of good fish in the sea" W.S. Gilbert > 1990's: Many fish stocks depleted due to overfishing, habitat loss, > and pollution. > 2000: Marine reserves, ecosystem restoration, and pollution reduction > MAY help restore populations. > 2022: Soylent Green is People! > > Confidentiality Notice: This e-mail message, including any > attachments, is for the sole use of the intended recipient(s) and may > contain confidential and privileged information. Any unauthorized > review, use, disclosure or distribution is prohibited. If you are not > the intended recipient, please contact the sender by reply e-mail and > destroy all copies of the original message. > -- Kevin E. McCluney Graduate Student School of Life Sciences Arizona State University Tempe, AZ 85287-4601 "I am only one; but still I am one. I cannot do everything, but still I can do something; I will not refuse to do something I can do." --Helen Keller
