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Acute Endothelial Benefits of Fat Restriction over Carbohydrate Restriction in Type 2 Diabetes Mellitus: Beyond Carbs and Fats.
Barbosa-Yañez, RL, Dambeck, U, Li, L, Machann, J, Kabisch, S, Pfeiffer, AFH
Nutrients. 2018;10(12)
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The control of type 2 diabetes mellitus has become a global challenge. Cardiovascular disease is a major cause of mortality in type 2 diabetes. The aim of the study is to examine and compare the effect of a hypocaloric very low carbohydrate diet versus hypocaloric low-fat diet on vascular function and visceral adipose tissue in type 2 diabetic patients. The study is a randomised parallel group intervention study with adult type 2 diabetes patients with an age range between 42 and 76 years. Results show that both dietary strategies effectively reduced body weight, total adipose tissue, visceral adipose tissue and lipid accumulation in the liver. However, participants following the low-fat diet experienced greater vascular function enhancements. Authors conclude that low-fat diet elicited advantageous effects on vascular function in patients with type 2 diabetes.
Abstract
BACKGROUND Cardiovascular diseases (CVD) are the major cause of mortality in type 2 diabetes patients (T2DM). The causes are embedded in a complex interplay between excess body fat, insulin resistance and serum lipid anomalies. Endothelial homeostasis is strongly affected by this pathogenic network. Even though metabolic changes and weight loss improve vascular endothelial function, the effect of different dietary approaches is still uncertain for type 2 diabetes patients. OBJECTIVE We aimed to compare the acute effects of a hypocaloric very low carbohydrate (VLC) diet versus a hypocaloric low fat (LF) diet on flow mediated dilation (FMD), intrahepatic lipid (IHL) accumulation and visceral adipose tissue as independent risk factors of CVD in T2DM patients. DESIGN 36 T2DM patients (age 63 ± 8 years, 60% females) were randomly assigned to the VLC diet (4⁻10% of total energy intake (E)) or to the LF diet (<30% E) for 3 weeks. Endothelial function was assessed by the flow mediated dilation (FMD) method. Adipose tissue depots and IHL were determined by magnetic resonance. RESULTS Both dietary strategies reduced body weight, body fat content and IHL. Unexpectedly, the LF group experienced significantly greater enhancement of FMD, compared to the VLC group. The FMD showed a positive correlation with protein intake and fat intake in the LF group, while it revealed a negative correlation with protein intake in the VLC diet group. CONCLUSIONS Reduction of total and hepatic adiposity was shown to be successful using either the VLC or LF hypocaloric diets, however, improvements in FMD may be related to the interplay of fat and protein intake.
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The Effect of Low-Carbohydrate Diet on Glycemic Control in Patients with Type 2 Diabetes Mellitus.
Wang, LL, Wang, Q, Hong, Y, Ojo, O, Jiang, Q, Hou, YY, Huang, YH, Wang, XH
Nutrients. 2018;10(6)
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Dietary intervention is a strategy to manage diabetes mellitus, as it can reduce the burden on islet cells and thus improve blood glucose levels, lipid profiles, and cognitive status. The aim of the study was to find out the effectiveness of the ‘six-point formula’ and the effects of a low-fat diet and low-carbohydrate diet on hyperglycaemia. The study is a prospective, single-blind randomized controlled trial which recruited 56 participants with type 2 diabetes mellitus. The participants were randomly allocated to receive either a low-fat diet or a low-carbohydrate diet. Results show that HbA1c levels (the average blood glucose levels in the last 2 – 3 months) in low-carbohydrate diet decreased significantly compared to the low-fat diet. The body mass index and the total cholesterol levels of the participants following the low-carbohydrate diet also decreased. Authors conclude that a low-carbohydrate diet can improve blood glucose, regulate blood lipids, reduce body mass index and decrease insulin doses more than a low-fat diet in Chinese patients with type 2 diabetes mellitus.
Abstract
OBJECTIVE In China, a low-fat diet (LFD) is mainly recommended to help improve blood glucose levels in patients with type 2 diabetes mellitus (T2DM). However, a low-carbohydrate diet (LCD) has been shown to be effective in improving blood glucose levels in America and England. A few studies, primarily randomized controlled trials, have been reported in China as well. METHOD Firstly, we designed two 'six-point formula' methods, which met the requirements of LCD and LFD, respectively. Fifty-six T2DM patients were recruited and randomly allocated to the LCD group (n = 28) and the LFD group (n = 28). The LCD group received education about LCD's six-point formula, while the LFD group received education about LFD's six-point formula. The follow-up time was three months. The indicators for glycemic control and other metabolic parameters were collected and compared between the two groups. RESULTS Forty-nine patients completed the study. The proportions of calories from three macronutrients the patients consumed met the requirements of LCD and LFD. Compared to the LFD group, there was a greater decrease in HbA1c level in the LCD group (-0.63% vs. -0.31%, p < 0.05). The dosages of insulin and fasting blood glucoses (FBG) in the third month were lower than those at baseline in both groups. Compared with baseline values, body mass index (BMI) and total cholesterol (TC) in the LCD group were significantly reduced in the third month (p < 0.05); however, there were no statistically significant differences in the LFD group. CONCLUSIONS LCD can improve blood glucose more than LFD in Chinese patients with T2DM. It can also regulate blood lipid, reduce BMI, and decrease insulin dose in patients with T2DM. In addition, the six-point formula is feasible, easily operable, and a practical educational diet for Chinese patients with T2DM.
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Anti-Inflammatory Effects of a Vegan Diet Versus the American Heart Association-Recommended Diet in Coronary Artery Disease Trial.
Shah, B, Newman, JD, Woolf, K, Ganguzza, L, Guo, Y, Allen, N, Zhong, J, Fisher, EA, Slater, J
Journal of the American Heart Association. 2018;7(23):e011367
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Inflammation plays a central role in the progression of atherosclerosis and is associated with adverse cardiovascular events. The aim of this study was to determine the effects of a vegan versus American Heart Association (AHA)-recommended diet on high-sensitivity C-reactive protein (hsCRP) [a type of protein found in blood plasma], as well as other markers of inflammation, glucometabolic markers, and lipid profiles in patients with established coronary artery disease (CAD) on guideline-directed medical therapy. This study is a prospective, randomized, open-label, blinded end point study design. The active study duration was 8 weeks, with an interim visit at 4 weeks and a final visit at 8 weeks. Results show: - a significantly greater reduction in hsCRP with a vegan versus AHA-recommended diet in patients with established CAD on guideline-directed medical therapy. - that the degree of weight loss, as measured by both body mass index and waist circumference, did not significantly differ between the 2 diet groups. - that markers of glycaemic control and lipid profiles, overall, also did not significantly differ in the vegan diet group when compared with the AHA-recommended diet group. Authors conclude that in patients with CAD and an elevated hsCRP, despite guideline-directed medical therapy, a vegan diet may be considered to further lower the parameters of inflammation.
Abstract
Background Dietary interventions may play a role in secondary cardiovascular prevention. hsCRP (High-sensitivity C-reactive protein) is a marker of risk for major adverse cardiovascular outcomes in coronary artery disease. Methods and Results The open-label, blinded end-point, EVADE CAD (Effects of a Vegan Versus the American Heart Association-Recommended Diet in Coronary Artery Disease) trial randomized participants (n=100) with coronary artery disease to 8 weeks of a vegan or American Heart Association-recommended diet with provision of groceries, tools to measure dietary intake, and dietary counseling. The primary end point was high-sensitivity C-reactive protein. A linear regression model compared end points after 8 weeks of a vegan versus American Heart Association diet and adjusted for baseline concentration of the end point. Significance levels for the primary and secondary end points were set at 0.05 and 0.0015, respectively. A vegan diet resulted in a significant 32% lower high-sensitivity C-reactive protein (β, 0.68, 95% confidence interval [0.49-0.94]; P=0.02) when compared with the American Heart Association diet. Results were consistent after adjustment for age, race, baseline waist circumference, diabetes mellitus, and prior myocardial infarction (adjusted β, 0.67 [0.47-0.94], P=0.02). The degree of reduction in body mass index and waist circumference did not significantly differ between the 2 diet groups (adjusted β, 0.99 [0.97-1.00], P=0.10; and adjusted β, 1.00 [0.98-1.01], P=0.66, respectively). There were also no significant differences in markers of glycemic control between the 2 diet groups. There was a nonsignificant 13% reduction in low-density lipoprotein cholesterol with the vegan diet when compared with the American Heart Association diet (adjusted β, 0.87 [0.78-0.97], P=0.01). There were no significant differences in other lipid parameters. Conclusions In patients with coronary artery disease on guideline-directed medical therapy, a vegan diet may be considered to lower high-sensitivity C-reactive protein as a risk marker of adverse outcomes. Clinical Trial Registration URL http://www.clinicaltrials.gov . Unique identifier: NCT 02135939.