Is Vegetarian Diet Healthier - Essay Example

A vegetarian diet is healthier". Discuss this ment using evidence from epidemiological studies. Introduction Many common life-threatening diseases in the world are attributed to lifestyle and diet. These include hypertension, hyperlipidemia, coronary artery disease, cancer and obesity. Quite a few epidemiological studies have suggested that vegetarian diet, along with appropriate lifestyle measures like regular physical activity and abstinence from smoking and excessive alcohol helps in decreasing the incidence of these diseases (Sesagothy & Phillips 1999). There are several types of vegetarian diet. These include (Laino 2006): 1. Vegan diet: This diet consists exclusively plant based foods. Milk, eggs and even honey are not included in the diet along with animal meat, fish and poultry. 2. Lacto-vegetarian diets: This diet includes milk and milk products but excludes other animal, fish or poultry based diet. 3. Lacto-ovo-vegetarian diet: This includes eggs, milk and milk products in the vegetarian diet. 4. Semi-vegetarian diets: These include small amounts of fish and poultry in the vegetarian diet but excludes animal meat. Most researchers consider lacto-ovo-vegetarian diet as standard vegetarian diet (Laino 2006, de Luis Román 2007). The benefits of wholesome vegetarian diet over diets containing meat and other foods of animal origin are due to lower intakes of saturated fat, cholesterol and animal protein, higher intakes of complex carbohydrates, dietary fiber, magnesium, folic acid, vitamin C and E, carotenoids and other phytochemicals (Leitzmann 2005). Influence of vegetarian diet on various diseases Diabetes mellitus: Diabetes prevalence is relatively low among individuals following plant-based and vegetarian diet. This is because these diets are low in fat and high in fiber and thus cause associated reductions in dietary energy density and energy intake (Howarth 2001). Barnard et al (2006) investigated the effects of low-fat vegan diet on glycemic control and cardiovascular risk factors in individuals with type 2 diabetes and found that such a diet had significant clinical improvements in the glycosylated hemoglobin levels, weight, body-mass index, waist circumference, total cholesterol and LDL cholesterol. However, in this study, the participants also followed strict exercise regime, making it difficult to attribute the results to diet alone. Another study by Barnard et al (2005) investigated the effects of vegetarian diet on similar aspects but without including exercise regime. The researchers concluded that this diet was associated with significant weight loss and improved glycemic and lipid control in type 2 diabetic patients. A low fat vegetarian diet delays glucose absorption, reduces fasting serum glucose levels of as much as 6–27%, lowers insulin requirements by as much as 40%, increases peripheral tissue insulin sensitivity, improves serum lipid profile by 10-32%, aids in weight control and lowers blood pressure (Segasothy and Phyllips 1999). Cardiac diseases: Elevated total cholesterol and LDL cholesterol are risk factors for coronary artery disease. Since vegetarian diet keeps these lipids under control, it can be said that this diet helps reducing the risk for coronary artery disease. La vecchia et al (1998) did a household multipurpose study in Italy and observed inverse relations between vegetable consumption and myocardial infarction and angina pectoris. Key et al (1998) studied the mortality in vegetarians and non-vegetarians with respect to ischemic heart disease, cerebrovascular disease, cancers of the stomach, large bowel, lung, breast and prostate, and for all causes of death. They reported that vegetarians had a 24% reduction in mortality from ischemic heart disease, but the mortality rates from the other causes of death examined were similar. Fontana et al (2007) evaluated the effects of vegetarian diet on cardiometabolic risk and opined that long-term consumption of a low-calorie low-protein vegan diet is associated with low cardiometabolic risk. In their study, plasma concentrations of lipids, lipoproteins, glucose, insulin, C-reactive protein, blood pressure (BP), and carotid artery intima-media thickness were lower in the low-calorie low-protein vegan diet than in the Western diet group. They also opined that diet higher in potassium and fiber decreased blood pressure. Various other studies have shown that frequent consumption of nuts provides protection against coronary heart disease (Segasothy and Phyllips, 1999). Nuts are supposed to be rich in protein, monounsaturated fatty acids like oleic acid, vitamins like vitamin E, B6, folic acid and niacin, minerals and fiber and walnuts in particular are rich in the polyunsaturated fatty acids, linoleic and linolenic acids. Infact, walnuts, macadamia, almonds and hazelnuts have cholesterol-lowering properties (Segasothy and Phyllips, 1999). Vegetarian diet not only decreases the risk of cardiac disease but also decreases the non-fatal and fatal end points including angina pectoris, electrocardiographic changes after exercise, left ventricular hypertrophy, ventricular ectopics and sudden death post-myocardial infarction (Segasothy and Phyllips, 1999). The beneficial effects of the vegetarian diet in decreasing the risk of cardiovascular disease can be attributed to mainly hypolipidemic effect, reduction in weight and reduction in blood pressure. Some specific vegetarian diets have been known to produce these effects. Diets like fruits, dried beans, legumes, guar gums, barley, psyllium and oat cereals are rich in fibers and have lipid lowering properties (Segasothy and Phyllips, 1999). Soy-bean protein has profound effect in the reduction of serum cholesterol and triglycerides level. Infact, it is estimated that ingestion of 25 or 50 g of soy protein per day can decrease serum cholesterol by 8.9%. This can be done by drinking two cups of soy milk per day. The benefits of soy-protein are probably due to the amino-acid pattern and peptide structure of the protein and from non-protein compounds such as isoflavones or phytoestrogens and saponins (Segasothy and Phyllips, 1999). It has been reported that consumption of 30 g dried legumes daily over a 3-month period resulted in a 16% decrease in serum cholesterol in hyperlipidaemia patients, and substitution of about 140 g dried beans like kidney beans, pinto beans, chick peas, green lentils and red lentils daily for other sources of starch like rice, and wheat over a 4-month period in hyperlipidemic patients resulted in a 7% decrease in total serum cholesterol and a 25% reduction in serum triglycerides (Segasothy and Phyllips, 1999). Stroke: Vegetarian diet decreases blood pressure and atherosclerosis and thus decreases the risk of stroke. Simon et al (1995) studied the relationship between serum fatty acids, which reflect dietary intake, and stroke. They reported that higher serum levels of the essential fatty acid {alpha}-linolenic acid are independently associated with a lower risk of stroke in middle-aged men at high risk for cardiovascular disease. Though some studies (Sauvaqet et al 2003) have reported that intake of animal products such as eggs, dairy products, and fish may be protective against intracerebral haemorrhage, they have not been able to relate cerebral infarction mortality to vegetarian diets. Infact, Gillman et al (1995) reported the protective effects of fruits and vegetables on the development of stroke in men. Also, various studies have demonstrated the protective effects of dietary antioxidant vitamins like carotene, Vitamin C and Vitamin E against stroke (Segasothy and Phyllips, 1999). Dementia: Though, some studies (Williams & OConnell 2002) have shown that diet rich in fish may ameliorate Alzheimers disease when compared to vegetarian diet, other studies have proved that vegetarian diet slows the progression of this disease due to increased oxidant intake (Segasothy and Phyllips, 1999). Giem et al (1993) also reported that vegetarian diet delays onset of dementia. Cancerous conditions Dietary fiber has a protective role against colon cancer. In a study by Wakai et al (2007) held in Japan, the researchers reported that dietary fiber has protective effect against colon cancer. In another study by Schatzkin et al (2007), the researchers reported that it was whole grain consumption and not dietary fiber that was associated with reduced risk of colorectal cancer. Fiber reduces fecal mutagen concentrations by increasing fecal bulk, reducing fecal transit time and by inhibiting fecal mutagen synthesis through fiber-induced changes in colonic pH or bacterial metabolism, thus reducing the exposure of colonic mucosa to fecal mutagens (Segasothy and Phyllips, 1999). Various other epidemiological studies have reported the decreased risk of breast cancer with high dietary fiber intake, high intakes of whole grains, vegetables and fruits. Dietary fiber lowers circulating levels of estrogens and thus decreases the risk of breast cancer (Segasothy and Phyllips, 1999). Infact, many studies have shown that there is a decreased risk of breast cancer in those with high intake of soy bean products, probably due to presence of chemopreventing agents such as phytosterols, sitosterols, phytoestrogens, saponins, Bowman Birk inhibitor and chymostatin. The phytoestrogens in soy protein exert an anti-estrogenic effect by competing with estradiol for oestrogen receptors in breast tissue. Also, daily ingestion of soy protein lengthens the menstrual cycle and suppresses the usual mid-cycle surge in pituitary gonadotropins, thus further preventing breast cancer (Segasothy and Phyllips, 1999). Other cancers which are reduced by consuming higher dietary levels of fruits and vegetables are lung, oral, pancreas, larynx, oesophagus, bladder and stomach. These effects are probably due to the presence of antioxidants such as vitamins E and C and carotenoids (Segasothy and Phyllips, 1999). Other diseases: La vecchia et al (1998) found an inverse relationship between vegetable consumption, chronic bronchitis, bronchial asthma, peptic ulcer, gallstones, liver cirrhosis, kidney stones, and arthritis. Vegetarian diet also decreases the risk of age-related macular degeneration due to increased intake of carotenoids, lutein and zeaxanthin through diet like carrot, spinach, collard greens, green leafy vegetables and other colored fruits and vegetables (Segasothy and Phyllips, 1999). Conclusion Vegetarian diet is healthier than non-vegetarian diet. This fact has been proved by various epidemiological studies showing the decreased incidence and risk of various diseases like coronary artery disease, diabetes mellitus-2, stroke, cancerous conditions and senile macular degeneration in those who consume this diet. The positive benefits of the diet can be attributed to hypolipidemic, antioxidant and anti-estrogenic properties, along with reduction in blood pressure and weight. References Barnard, N.D., Scialli, A.R., Turner-McGrievy, G., Lanou, A.J., Glass, J., 2005. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med., 118, p.991–997. Barnard, N.D., Cohen, J., Jenkins, D.J., 2006. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care, 29(8), p.1777-83. Available at: http://care.diabetesjournals.org/cgi/content/full/29/8/1777 [16 December 2007] Fontana, L., Meyer, T.E., Klein, S., Holloszy, J.O., 2007. Long-term low-calorie low-protein vegan diet and endurance exercise are associated with low cardiometabolic risk. Rejuvenation Res., 2007 Jun;10(2), p.225-234. Giem P, Beeson WL, Fraser GE., 1993. The incidence of dementia and intake of animal products: preliminary findings from the Adventist Health Study. Neuroepidemiology,12(1), p.28-36 Gillman, M.V., Cupples, L.A., Gagnon, D., Posner, B.M., Ellison, R.C., Castelli, W.P., et al., 1995. Protective effect of fruits and vegetables on development of stroke in men. JAMA, 723, p.1113–17. Howarth, N.C., Saltzman, E., Roberts, S.B., 2001. Dietary fiber and weight regulation (Review). Nutr Rev., 59, p.129–139. Key, T.J., Fraser, G.E., Thorogood, M., et al., 1998. Mortality in vegetarians and non-vegetarians: a collaborative analysis of 8300 deaths among 76,000 men and women in five prospective studies. Public Health Nutrition, 1, p.33-41. Laino, C., 2006. Vegetarian Diet Chews Up Excess Flab. WenMDHealth. Available at: http://www.medscape.com/viewarticle/547854 [16 December 2007] La vecchia, C.L., Decarli, A., Pagano, R., 1998. Vegetable consumption and risk of chronic disease. Epidemiology, 9, p. 208–210. Leitzmann, C., 2005. 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