ABC | Volume 110, Nº5, May 2018

Original Article Navarro et al Metabolic Syndrome in Vegetarian and Omnivorous Men Arq Bras Cardiol. 2018; 110(5):430-437 In a sample of 391 female VEG and 315 OMN from Taiwan, the VEG status was associated with lower BMI, smaller WC, lower TC, LDL-c, HDL-c, TC/HDL-c and LDL-c/HDL-c ratios. 9 Regarding the differences in CRF between VEG and OMN, one seems more consistent in the literature, the difference in blood pressure. In an elderly Taiwanese population, SBP was independently associated with VEG status, 11 and a recent meta-analysis confirms that a VEG diet is associated with lower blood pressure. 4 Despite scientific plausibility that can explain the impact of the higher fat content of the OMN diet on lipid metabolism, a large number of studies has found that glucose profile is improved by adopting a VEG diet. In a study conducted with a sample of 425 adults from the Isfahan Diabetes Prevention Study, a population-based prospective cohort in Iran, the VEG dietary pattern was inversely associated with the risk of abnormal FSG levels. 3 In Taiwan, OMN had a greater risk of developing high FSG (HR: 1.16, 95%CI 1.02-1.32). 12 In our study, similar differences were observed in indices evaluated in glucose metabolism. We found no difference between the levels of HDL-c, but other studies have found statistical differences in this lipoprotein. Gadgil et al. 13 have observed a higher amount of HDL-c in VEG Asian Indians living in the San Francisco Bay area. In São Paulo, VEG individuals have higher HDL-c too. 28 In Taiwan, OMN individuals had a smaller risk of having lower HDL-c. 12 A significantly greater number of VEG individuals was classified as physically active compared to OMN individuals. Data from the Elderly Nutrition and Health Survey in Taiwan (1999–2000) have shown that regular exercise was independently associated with VEG status. 11 Pimentel has observed a higher tendency to be physically active among VEG individuals living in São Paulo, compared to OMN individuals. 30 In this study, VEG individuals were more physically active; however, the observed differences in CRF were due to neither physical activity nor caloric intake. In our study, the OMN diet was associated with the prevalence of MSyn and alterations in most of the MSyn components (WC, SBP, DBP, and FSG), independently of caloric intake, age, and level of physical activity. Some studies with different populations have shown this association, as discussed below. A study aiming to verify the association of MSyn risk factors with selected markers of oxidative status (advanced glycation end products, advanced oxidation protein products) and microinflammation (C-reactive protein and leukocytes) in healthy OMN and VEG individuals has found that OMN individuals consumed significantly more protein, total fat, saturated as well as unsaturated fatty acids, and dietary cholesterol, and less dietary fiber; in addition, the VEG diet seems to exert beneficial effects on MSyn and risk factors associated with microinflammation. 10 Rizzo et al . 8 have observed in subjects from the Adventist Health Study 2 that a VEG dietary pattern was associated with a lower risk of MSyn, and this relationship persists after adjusting for lifestyle and demographic factors. For the female VEG individuals from a Buddhist hospital in Taiwan, the risks for MSyn were lower for ovo-lacto-vegetarians of 1–11 years and > 11 years, respectively, 45% and 42%, compared to OMN individuals after adjusting for other covariates. 9 It should be noted that although the sample from the CARVOS study includes only men who are self-assessed as "healthy", many individuals were found to have MSyn among those who consumed an OMN diet. MSyn is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increase the risk of atherosclerotic cardiovascular disease, type 2 diabetes mellitus, and all-cause mortality. Lifestyle is one of the major predisposing factors of MSyn. 31 In our study, the multivariate regression models show that the VEG diet was independently the best indicator of MSyn, and was associated with its components WC, SBP, DBP, and FSG, suggesting that the prevalence of MSyn could be due to the influences on its components. We hypothesize that the mechanism responsible for these differences exists in the composition of one’s diet. VEG subjects consume smaller amounts of total fat, saturated fat, and cholesterol, and larger amounts of unsaturated fat and fiber than OMN subjects do. 10,14 The absence of red and processed meat intake could have an additional role. 14 In our study, VEG and OMN individuals did not have a significant difference incaloric intake. VEGconsumed significantly more carbohydrates, dietary fiber, and polyunsaturated fat. Moreover, OMN significantly ingested larger amounts of protein, total fat, saturated fat, and monounsaturated fat. In addition, dietary patterns like VEG and theMediterranean diet have a beneficial synergistic combination of antioxidants, fiber, potassium, magnesium, and phytochemicals, 31 which may be responsible for the health benefits demonstrated in several scientific studies. There are some limitations to this study. It had a relatively small number of subjects, and the cross-sectional design did not allow us to draw conclusions in terms of causal relationships. Future research must be conducted, especially prospective cohort studies in different populations to prove the impact of the vegetarian diet on the outcomes evaluated in this study. The strength of our study is its highly homogenized sample, where all were nonsmokers, had no previous diagnosis of diabetes, dyslipidemia, cardiovascular or cerebrovascular diseases, hypertension or intake of antihypertensive medication, and had no difference in the frequency of alcohol beverage intake. The only difference between groups was our independent variable, diet, and physical activity, which was demonstrated but did not account for the differences found. In addition, we found in the same sampling a better profile of subclinical vascular disease evaluated by arterial stiffness, determined by carotid-femoral pulse wave velocity and carotid intima-media thickness, and distensibility in VEG compared to OMN subjects. 20 435