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I will be discussing in this assignment if a vegetarian diet offers the world a future full of hope and promise. From a consumer's and environmental perspective, there are growing concerns about meat and egg production in Europe and North America.
Vegetarian diets typically contain similar levels of iron to non-vegetarian diets but, this has a lower bioavailability than iron from meat sources and its absorption can sometimes be inhibited by other dietary constituents.
Vegetarian foods are rich in iron include: black beans, cashews, hempseed, kidney beans, lentils, oatmeal, raisins, black-eyed peas, soybeans, many breakfast cereals, sunflower seeds, chickpeas, tomato juice, tempeh, molasses, thyme, and whole-wheat bread. The related vegan diets can often be higher in iron than vegetarian diets because, dairy products are low in iron. Iron stores often tend to be lower in vegetarians than non-vegetarians and a few small studies report higher rates of iron deficiency. However, the American Dietetic Association saying that iron deficiency is no more common in vegetarians than non-vegetarians (adult males are rarely iron deficient); iron deficiency anaemia is rare no matter the diet.
The consumption of meat can cause a transmission of a number of diseases from animals to humans. The connection between infected animal and human illness is well established in the case of salmonella; an estimated one-third to one-half of all chicken meat marketed in the United States is contaminated with salmonella. Only recently, however, have scientists begun to suspect that there is a similar connection between animal meat and human cancer, birth defects, mutations, and many other diseases in humans. In 1975, one study found 75 percent of supermarket samples of cow's milk and 75 percent of egg samples to contain the leukemia (cancer) virus. By 1985, nearly 100 percent of the eggs tested or the hens they came from had the cancer virus. The rate of disease among chickens is so high that the Department of Labour has ranked the poultry industry as one of the most hazardous occupations. 20 percent of all cows are afflicted with a variety of cancer known as bovine leukemia virus (BLV). Studies have increasingly linked BLV with HTLV-1, the first human retrovirus discovered to cause cancer. Scientists have found that a bovine immunodeficiency virus (BIV), the equivalent of the AIDS virus in cows can also infect human cells. It is supposed that BIV may have a role in the development of a number of malignant or slow viruses in humans.
The proximity of animals in industrial-scale animal farming leads to an increased rate of disease transmission. Transmission of animal influenza viruses to humans has been documented but, illness from such cases is rare compared to that caused by the now common human-adapted older influenza viruses which is transferred from animals to humans in the more distant past. The first documented case was in 1959, and in 1998. 18 new human cases of H5N1 influenza were diagnosed in which six people died. In 1997 more cases of H5N1 avian influenza were found in chickens in Hong Kong.
Libby Sander argued in a blog for USA Today that Vegetarianism reduces E. coli infections and in a piece for The New York Times linked E. coli contamination in food to industrial scale meat and dairy farms. E. coli infections in the US during 2006 were traced to spinach and onions.
Transmission of pathogenic E. coli often occurs via fecal-oral transmission. Common routes of transmission include unhygienic food preparation and farm contamination. Dairy and beef cattle are primary reservoirs of the E. coli strain O157:H7 and they can carry it asymptomatically and shed it in their feces. Food products associated with E. coli outbreaks include raw ground beef, raw seed sprouts or spinach, raw milk, unpasteurized juice, and foods contaminated by infected food workers via fecal-oral route. In 2005, some people who had consumed triple-washed and pre-packaged lettuce were infected with E. coli. In 2007, packaged lettuce salads were recalled after they were found to be contaminated with E. coli.
E. coli outbreaks have been traced to unpasteurized apples, orange juice, milk, alfalfa sprouts, and water.
A study by the Institute of Preventive and Clinical Medicine and Institute of Physiological Chemistry looked at a group of 19 vegetarians (lacto-ovo) and used as a comparison a group of 19 omnivorous subjects recruited from the same region. The study found that this group of vegetarians (lacto-ovo) have a significantly higher amount of plasma carboxymethyllysine and advanced glycation end products (AGEs) compared to this group of omnivores. Carboxymethyllysine is a glycation product which represents a general marker of oxidative stress and long-term damage of proteins in aging atherosclerosis and diabetes. Advanced glycation end products (AGEs) may play an important adverse role in process of atherosclerosis, diabetes aging and chronic renal failure.
Plants are not generally significant sources of Vitamin B12. However, vegetarians can obtain B12 from dairy products and eggs, and vegans can obtain it from fortified foods and dietary supplements. Since the human body preserves B12 and reuses it without destroying the substance, clinical evidence of B12 deficiency is uncommon. The body can preserve stores of the vitamin for up to 30 years without needing its supplies to be replenished. The only reliable vegan sources of B12 are foods fortified with B12 (including some soy products and some breakfast cereals) and B12 supplements. The research on vitamin B12 sources has increased in the latest years.
Calcium intake in vegetarians is similar to non-vegetarians. Some impaired bone mineralisation has been found among vegans who do not consume enough leafy greens, which are sources of abundant calcium. However, this is not found in lacto-ovo vegetarians. Some sources of calcium include collard greens, bok choy, kale, turnip greens, spinach, Swiss chard and beet greens are high in calcium but, the calcium is bound to oxalate and therefore it is poorly absorbed. Vitamin D levels do not appear to be lower in vegetarians (although studies have shown that much of the general population is deficient). The Vitamin D needs can be met via the human body's own generation upon sufficient and sensible UV sun exposure. Products including milk, soy milk and cereal grains may be fortified to provide a good source of Vitamin D  also, mushrooms provide over 2700 IU per serving (approx. 3 oz or 1/2 cup) of vitamin D2 and if exposed to just 5 minutes of UV light after being harvested; for those who do not get adequate sun exposure or food sources then, Vitamin D supplementation may be necessary.
Fish is a non-vegetarian source of Omega 3 fatty acids. Plant-based or vegetarian sources exist in such as soy, walnuts, pumpkin seeds, canola oil and especially hempseed, chia seed, flaxseed, and purslane. By obtaining protein from these sources-the essential amino acids can also be obtained by eating a variety of complementary plant sources that in combination provide all eight essential amino acids (e.g. brown rice and beans or hummus and whole wheat pita though protein combining in the same meal is not necessary). A varied intake of such sources can be adequate as in year 1994 study found.
Purslane contains more of Omega 3 than any other known leafy green.
Plant foods can provide alpha-linolenic acid but not the long-chain n-3 fatty acids EPA and DHA which are found in low levels in eggs and dairy products. Vegetarians and particularly vegans have lower levels of EPA and DHA than meat-eaters. While the health effects of low levels of EPA and DHA are unknown, it is
unlikely that supplementation with alpha-linolenic acid will significantly increase levels. Recently, some companies have begun to market vegetarian DHA supplements containing seaweed extracts. Similar supplements providing both DHA and EPA have also begun to appear. Whole seaweeds are not suitable for supplementation because their high iodine content the limits of amount that may be safely consumed. However, certain algae such as spirulina are good sources of gamma-linolenic acid (GLA), alpha-linolenic acid (ALA), linoleic acid (LA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA).
In year 1999 met study combined a data of five studies from western countries. The met study reported mortality ratios, where lower numbers indicated fewer deaths for fish eaters to be .82, vegetarians to be .84, occasional meat eaters to be .84.
Regular meat eaters and vegans shared the highest mortality ratio of 1.00. The study reported the numbers of deaths in each category and expected error ranges for each ratio of adjustments made to the data. However, the "lower mortality was due largely to the relatively low prevalence of smoking in these cohorts". Out of the major causes of death studied only one difference in mortality rate was attributed to the difference in diet as the conclusion states: "vegetarians had a 24% lower mortality from ischemic heart disease than non vegetarians, but no associations of a vegetarian diet with other major causes of death were established."
In Mortality in British vegetarians, a similar conclusion is drawn: British vegetarians have low mortality compared with the general population. Their death rates are similar to those of comparable non-vegetarians, suggesting that much of this benefit may be attributed to non-dietary lifestyle factors such as a low prevalence of smoking and a generally high socio-economic status, or to aspects of the diet other than the avoidance of meat and fish.
The Adventist health study is again incorporated into a met study titled "Does low meat consumption increase life expectancy in humans?" published in American Journal of Clinical Nutrition, which concluded that low meat eating (less than once per week) and other lifestyle choices significantly increase life expectancy, relative to a group with high meat intake. The study concluded that the findings from one cohort of a healthy adult's raises the possibility that long-term (2 decades) adherence to a vegetarian diet can further produce a significant 3.6-y increase in life expectancy. However, the study also concluded that some of the variation in the survival advantage in vegetarians may have been due to marked the differences between studies in adjustment for confounders: the definition of vegetarian, the measurement error, the age distribution, the healthy volunteer effect and intake of specific plant foods by the vegetarians. It further states that this raises the possibility that a low-meat and high plant-food dietary pattern may be the true causal protective factor rather than simply elimination of meat from the diet. In a recent review of studies relating low-meat diet patterns to all-cause mortality Singh noted that 5 out of 5 studies indicated that adults who followed a low meat in high plant-food diet pattern experienced significant or marginally significant decreases in mortality risk relative to other patterns of intake.
Statistical studies such as comparing life expectancy with regional areas and local diets in Europe also have found life expectancy considerably greater in southern France, where a low meat in high plant Mediterranean diet is common than northern France from where a diet with high meat content is more common.
Salmonella outbreaks have been traced to peanut butter, frozen pot pies and puffed vegetable snacks. BSE also known as mad cow disease is linked by the World Health Organization to Creutzfeldt-Jakob disease in humans.
There have been reports of fears of foot-and-mouth disease in sheep.
PCBs in farmed salmon, mercury in fish, dioxin concentrations in animal products, artificial growth hormones, antibiotics, lead and mercury, pesticide contamination of vegetables and fruits and banned chemicals being used to ripen fruits. In 2005, fears that "bird flu" could be caused by eating chicken were featured in a PETA call for vegetarian diets.
In Western medicine, patients are sometimes advised to adhere to a vegetarian diet. Vegetarian diets have been used as a treatment for rheumatoid arthritis, but the evidence is inconclusive whether this is effective.
Certain alternative medicines, such as Ayurveda and Siddha, prescribe a vegetarian diet as a normal procedure.
The Vegetarian Resource Group, among others, has concluded that humans are naturally omnivores based on the human ability to digest meat, as well as plant foods. Other arguments hold that humans are more anatomically similar to herbivores, with long intestinal tracts and blunt teeth, unlike omnivores and carnivores. Nutritional experts believe that early hominids evolved into eating meat as a result of huge climatic changes that took place three to four million years ago, when forests and jungles dried up and became open grasslands and opened hunting and scavenging opportunities.
Whether tuberculosis originated in cattle and was then transferred to humans or diverged from a common ancestor infecting a different species is currently unclear. The strongest evidence for a domestic-animal origin exists for measles and pertussis although the data do not exclude a non-domestic origin.
According to the 'Hunter Theory', the simplest and most plausible explanation for the cross-species transmission the AIDS virus was transmitted from a chimpanzee to a human when a bush meat hunter was bitten or cut while hunting or butchering an animal.
Historian Norman Cantor suggests the Black Death might have been a combination of pandemics including a form of anthrax and cattle murrain. He cites many forms of evidence including the fact that meat from infected cattle was known to have been sold in many rural English areas prior to the onset of the plague.
The American Dietetic Association indicates that vegetarian diets may be more common among adolescents with eating disorders but that the evidence suggests that the adoption of a vegetarian diet does not lead to eating disorders, rather that "vegetarian diets may be selected to camouflage an existing eating disorder." Other studies and statements by dieticians and counsellors support this conclusion.
To conclude, from my experience a vegetarian diet will benefit a young and old generation and will avoid many diseases and health problems in our society.