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Efficacy of a 2-Month Very Low-Calorie Ketogenic Diet (VLCKD) Compared to a Standard Low-Calorie Diet in Reducing Visceral and Liver Fat Accumulation in Patients With Obesity.
Cunha, GM, Guzman, G, Correa De Mello, LL, Trein, B, Spina, L, Bussade, I, Marques Prata, J, Sajoux, I, Countinho, W
Frontiers in endocrinology. 2020;11:607
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Excess fat in the liver, known as non-alcoholic fatty liver disease (NAFLD), has been shown to increase the risk of chronic diseases such as type 2 diabetes. Standard treatment regimens consist of low-calorie (LC) diets and exercise, however these may be ineffective at reversing fat accumulation in the liver. A very low-calorie ketogenic diet (VLCKD) has been proposed as an alternative treatment for NAFLD. This randomised control pilot study of 39 individuals with obesity aimed to compare LC diet and VLCKD on fat accumulation and indicators for NAFLD for two months. The results showed greater weight loss, abdominal fat reduction, liver fat reduction and improvements in liver function with VLCKD compared to the LC diet. Cholesterol was significantly reduced by both diets. However liver stiffness remained unchanged. The authors concluded that VLCKD was more successful at reducing liver fat and abdominal fat accumulation than current standard therapy and has the potential to improve NAFLD. Health care professionals could use this study to improve liver and abdominal fat loss in patients with obesity to improve NAFLD, when standard therapy has been inadequate.
Abstract
Background: Currently the treatment of non-alcoholic fatty liver disease (NAFLD) is based on weight loss through lifestyle changes, such as exercise combined with calorie-restricted dieting. Objectives: To assess the effects of a commercially available weight loss program based on a very low-calorie ketogenic diet (VLCKD) on visceral adipose tissue (VAT) and liver fat content compared to a standard low-calorie (LC) diet. As a secondary aim, we evaluated the effect on liver stiffness measurements. Methods: Open, randomized controlled, prospective pilot study. Patients were randomized and treated either with an LC or a VLCKD and received orientation and encouragement to physical activity equally for both groups. VAT, liver fat fraction, and liver stiffness were measured at baseline and after 2 months of treatment using magnetic resonance imaging. Paired t-tests were used for comparison of continuous variables between visits and unpaired test between groups. Categorical variables were compared using the χ2-test. Pearson correlation was used to assess the association between VAT, anthropometric measures, and hepatic fat fraction. A significance level of the results was established at p < 0.05. Results: Thirty-nine patients (20 with VLCKD and 19 with LC) were evaluated at baseline and 2 months of intervention. Relative weight loss at 2 months was -9.59 ± 2.87% in the VLCKD group and -1.87 ± 2.4% in the LC group (p < 0.001). Mean reductions in VAT were -32.0 cm2 for VLCKD group and -12.58 cm2 for LC group (p < 0.05). Reductions in liver fat fraction were significantly more pronounced in the VLCKD group than in the LC group (4.77 vs. 0.79%; p < 0.005). Conclusion: Patients undergoing a VLCKD achieved superior weight loss, with significant VAT and liver fat fraction reductions when compared to the standard LC diet. The weight loss and rapid mobilization of liver fat demonstrated with VLCKD could serve as an effective alternative for the treatment of NAFLD. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT04322110.
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Diet-induced weight loss alters hepatic glucocorticoid metabolism in type 2 diabetes mellitus.
Stomby, A, Otten, J, Ryberg, M, Andrew, R, Walker, BR, Olsson, T
European journal of endocrinology. 2020;182(4):447-457
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Cushing syndrome is caused by an overexposure to cortisol and associated with abdominal adiposity, hypertension, dyslipidaemia, insulin resistance and type 2 diabetes mellitus (T2DM), and therefore bears similarities with metabolic syndrome and obesity. Whilst circulating cortisol levels are normal or slightly decreased in obese individuals, they tend to be increased in T2DM. The aim of this study was to investigate associations between obesity and T2DM measures and glucocorticoid metabolism, and any possible effects of a palaeolithic diet (PD) with or without exercise. In this single-blind study (investigators examining patients were blind to intervention), 28 patients with overweight or obesity and T2DM were randomised to either a PD alone or combined with a structured resistance and aerobic exercise programme for 12 weeks. The PD was based on a high intake of vegetables, fruit, lean meat, nuts, egg, fish and seafood, whilst grains, sugar, salt, dairy products and refined fats were reduced. Body mass index, waist circumference, glycaemic control, liver and systemic insulin sensitivity improved in both groups with no statistically significant difference between groups. There was no association between insulin sensitivity and indices of tissue specific glucocorticoid metabolism. PD with and without exercise was associated with increased conversion of the inactive cortisone to the active cortisol through increased activity of the conversion enzyme in the liver, but not with increased urinary excretion of glucocorticoid metabolites. The authors concluded that the results suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.
Abstract
CONTEXT Altered tissue-specific glucocorticoid metabolism has been described in uncomplicated obesity and type 2 diabetes. We hypothesized that weight loss induced by diet and exercise, which has previously been shown to reverse abnormal cortisol metabolism in uncomplicated obesity, also normalizes cortisol metabolism in patients with type 2 diabetes. OBJECTIVE Test the effects of a diet intervention with added exercise on glucocorticoid metabolism. DESIGN Two groups followed a Paleolithic diet (PD) for 12 weeks with added 180 min of structured aerobic and resistance exercise per week in one randomized group (PDEX). SETTING Umeå University Hospital. PARTICIPANTS Men and women with type 2 diabetes treated with lifestyle modification ± metformin were included. Twenty-eight participants (PD, n = 15; PDEX, n = 13) completed measurements of glucocorticoid metabolism. MAIN OUTCOME MEASURES Changes in glucocorticoid metabolite levels in 24-h urine samples, expression of HSD11B1 mRNA in s.c. adipose tissue and conversion of orally administered cortisone to cortisol measured in plasma. Body composition and insulin sensitivity were measured using a hyperinsulinemic-euglycemic clamp, and liver fat was measured by magnetic resonance spectroscopy. RESULTS Both groups lost weight and improved insulin sensitivity. Conversion of orally taken cortisone to plasma cortisol and the ratio of 5α-THF + 5β-THF/THE in urine increased in both groups. CONCLUSIONS These interventions caused weight loss and improved insulin sensitivity with concomitant increases in the conversion of cortisone to cortisol, which is an estimate of hepatic HSD11B1 activity. This suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.
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Effect of purple sweet potato leaf consumption on the modulation of the antioxidative status in basketball players during training.
Chang, WH, Chen, CM, Hu, SP, Kan, NW, Chiu, CC, Liu, JF
Asia Pacific journal of clinical nutrition. 2007;16(3):455-61
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Purple sweet potato leaves (PSPLs) have a high polyphenol content and have been shown to exhibit free-radical scavenging properties. During a training period athletes experience exercise-induced oxidative stress, and many studies have indicated that polyphenols can help prevent oxidative damage. Currently there is limited information on the physiologic and biochemical effects of dietary PSPLs in humans. The aim of this crossover study was to examine the effect of PSPLs on a variety of antioxidant status biomarkers in fifteen elite basketball players. Participants were enrolled for seven weeks and consumed a PSPL-rich diet and a control diet with a washout period in between. This study found that PSPL consumption for two weeks led to a significant increase in total plasma polyphenol concentration and vitamin E and C levels, and demonstrated a protective effect on lipid and DNA oxidation. The authors conclude that can a polyphenol-rich diet can modulate the anti-oxidative status of athletes during a training period.
Abstract
The aim of this study was to evaluate the effect of purple sweet potato leaves (PSPLs) consumption on antioxidative status and its modulation of that status in basketball players during training period. Fifteen elite basketball players were enrolled in this study. The seven-week study consisted of a run-in (week 1), PSPLs diet (daily consumption of 200 g PSPLs) (weeks 2, 3), washout (weeks 4, 5), and control diet (low polyphenol, with the amount of carotenoids adjusted to the same level as that of PSPLs) (weeks 6, 7). Blood and urine samples were taken for biochemical analysis. Compared with the control group, the results showed that PSPLs consumption led to a significant increase of plasma polyphenol concentration and vitamin E and C levels. Low density lipoprotein (LDL) lag time was significantly longer in the PSPLs group. A significant decrease of urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) was noted; however, there was no significant change in plasma glutathione (GSH), total antioxidant status (TAS) and malondialdehyde + 4-hydroxy-2(E)-nonenal level after consuming the PSPLs diet. In conclusion, consumption of PSPLs diet for 2 weeks may reduce lipid and DNA oxidation that can modulate the antioxidative status of basketball players during training period.