Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes

Institute for Clinical and Experimental Medicine Charles University, 1st Faculty of Medicine Institute of Endocrinology, Prague, Czech Republic.
Diabetic Medicine (Impact Factor: 3.12). 05/2011; 28(5):549-59. DOI: 10.1111/j.1464-5491.2010.03209.x
Source: PubMed


The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes.
A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat.
Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat.
A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.

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    • "In contrast, some intervention trials demonstrated a greater improvement in insulin sensitivity, glycemic control and a reduction in oxidative stress markers in T2D patients consuming a vegetarian diet compared with those consuming a traditional diabetes diet [15], [16]. The aim of our study was to determine the acute effects of meat and plant-based meals on postprandial GIH secretion. "
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    ABSTRACT: The intake of meat, particularly processed meat, is a dietary risk factor for diabetes. Meat intake impairs insulin sensitivity and leads to increased oxidative stress. However, its effect on postprandial gastrointestinal hormone (GIH) secretion is unclear. We aimed to investigate the acute effects of two standardized isocaloric meals: a processed hamburger meat meal rich in protein and saturated fat (M-meal) and a vegan meal rich in carbohydrates (V-meal). We hypothesized that the meat meal would lead to abnormal postprandial increases in plasma lipids and oxidative stress markers and impaired GIH responses.
    PLoS ONE 09/2014; 9(9):e107561. DOI:10.1371/journal.pone.0107561 · 3.23 Impact Factor
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    • "In addition, clinical trials have reported that diet modification including high consumption of fruit and vegetables, caloric restriction, and consumption of lower glycemic index/glycemic load decreased the levels of hemoglobinA1c (HbA1c) of type 1 and 2 diabetes [10,11]. Also, several observational studies have shown that diet modification improved glycemic control [12,13], insulin resistance [14] and reduced risk of cardiovascular disease and overall mortality in diabetic patients [15]. "
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    ABSTRACT: It is generally accepted that diet modification provides beneficial effects on the management of diabetes. In the present study, we evaluated the effects of diet modification on nutrient intake and quality of life in a large sample of diabetic patients. This study was conducted using data from the Korea National Health and Nutrition Examination Survey IV and V (2007-2010). A total of 2,484 of diabetic patients were included in the analysis. Then, we compared the overall quality of dietary intake between diabetic patients with diet modification and those without dietary modification. The result showed that subjects on diabetic diet (DDG) showed lower levels of total cholesterol, triglyceride, and AST before and after the adjustment for covariates (all p < 0.05). The results of nutrient assessment showed that DDG had lower intakes of total energy, fat, and carbohydrate (all p < 0.05), but higher intakes of energy from protein, vitamin B1, vitamin B2, niacin and vitamin C than NDG. (all p < 0.05). In addition, nutritional adequacy ratio of calcium and vitamin B2 were significantly higher in DDG than those in normal diet group (NDG) (p < 0.05). However, we observed no significant differences in quality of life between two groups. In conclusion, diet modification in diabetic patients seemed to be effective to improve blood lipid profile and the adequacy of nutrient intake without sacrificing the quality of life.
    07/2014; 3(2):106-14. DOI:10.7762/cnr.2014.3.2.106
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    • "The methods of the 6-months randomized study are described in detail elsewhere [5]. Briefly: 74 subjects with type 2 diabetes treated by oral hypoglycemic agents were randomly assigned into one of two groups within the framework of an open parallel randomized study. "
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    ABSTRACT: Objective Our previous 6-months, randomized study demonstrated the beneficial effect of a vegetarian (V) compared to a conventional diet (C) with similar caloric restriction on cardiovascular risk factors for patients with type 2 diabetes (T2D), namely increased insulin sensitivity, reduced body weight, reduced volume of visceral and subcutaneous fat, decreased LDL-cholesterol and improved oxidative stress markers and chosen adipokines. We conducted post-trial monitoring to determine whether the improved outcomes persisted 1 year after the end of the study. Methods 62 subjects with T2D who completed the study were asked to come for a 1-year-follow-up to measure weight, waist circumference, HbA1c and blood lipids. No attempts were made to maintain their previously assigned diets. Results 44 patients (71%) attended the post-trial monitoring. Hypoglycemic agents were increased by 14% in V and by 26% in C; insulin therapy was introduced in 5% in V and in 13% in C one year after the end of the intervention. Neither weight nor waist circumference changed significantly in either group. HbA1c increased (p ≤ 0.05) similarly in both groups (+0.49 ± 1.04% in V vs. +0.42 ± 0.8% in C). Blood lipids did not change in either group. Conclusion One year after the end of the intervention, the positive effects of a vegetarian diet on cardiovascular risk factors compared to a conventional diet were partially maintained.
    Cor et vasa 04/2014; 56(2). DOI:10.1016/j.crvasa.2013.12.004
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