Effects of transcranial direct current stimulation associated with hypocaloric diet on glucose homeostasis in obesity.

OBJECTIVE: The aim of this study was to test the effects of repetitive active transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex (rDLPFC) associated with a hypocaloric diet on glucose homeostasis in people with excessive weight. METHODS: Adults with overweight or obesity were selected in a randomized, double-blind pilot study to complete 4 weeks (20 sessions) of fixed-dose tDCS (2 mA, 20 minutes) delivered over the rDLPFC and associated with a standard hypocaloric diet. Participants were randomly assigned (1:1) and stratified by sex to the active tDCS group (active) or the sham tDCS group (sham). Changes in glucose homeostasis were assessed in a 4-hour liquid meal tolerance test, performed before and after the intervention. RESULTS: Twenty-eight participants were randomized (79% with obesity; mean [SD] age 37.6 [5.8] years). After the intervention, fasting plasma glucose (mean [95% CI], -7.8 mg/dL [-14.0 to -1.6]) and insulin levels (-7.7 µIU/mL [-13.9 to -1.6]) decreased in the active compared with the sham. Similarly, the Matsuda insulin sensitivity index increase in the active (4.7 pmol-1  × mmol-1 [1.6 to 7.8]) compared with the sham (0.6 pmol-1  × mmol-1 [-1.4 to 3.2]). CONCLUSIONS: Repetitive, active tDCS over the rDLPFC could be a promising noninvasive technique to improve glucose homeostasis in individuals with overweight or obesity on a low-calorie diet, highlighting the importance of investigating this intervention modality in individuals with type 2 diabetes mellitus.

The effects of coconut oil on the cardiometabolic profile: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: Despite having a 92% concentration of saturated fatty acid composition, leading to an apparently unfavorable lipid profile, body weight and glycemic effect, coconut oil is consumed worldwide. Thus, we conducted an updated systematic review and meta-analysis of randomized clinical trials (RCTs) to analyze the effect of coconut oil intake on different cardiometabolic outcomes. METHODS: We searched Medline, Embase, and LILACS for RCTs conducted prior to April 2022. We included RCTs that compared effects of coconut oil intake with other substances on anthropometric and metabolic profiles in adults published in all languages, and excluded non-randomized trials and short follow-up studies. Risk of bias was assessed with the RoB 2 tool and certainty of evidence with GRADE. Where possible, we performed meta-analyses using a random-effects model. RESULTS: We included seven studies in the meta-analysis (n = 515; 50% females, follow up from 4 weeks to 2 years). The amount of coconut oil consumed varied and is expressed differently among studies: 12 to 30 ml of coconut oil/day (n = 5), as part of the amount of SFAs or total daily consumed fat (n = 1), a variation of 6 to 54.4 g/day (n = 5), or as part of the total caloric energy intake (15 to 21%) (n = 6). Coconut oil intake did not significantly decrease body weight (MD -0.24 kg, 95% CI -0.83 kg to 0.34 kg), waist circumference (MD -0.64 cm, 95% CI -1.69 cm to 0.41 cm), and % body fat (-0.10%, 95% CI -0.56% to 0.36%), low-density lipoprotein cholesterol (LDL-C) (MD -1.67 mg/dL, 95% CI -6.93 to 3.59 mg/dL), and triglyceride (TG) levels (MD -0.24 mg/dL, 95% CI -5.52 to 5.04 mg/dL). However, coconut oil intake was associated with a small increase in high-density lipoprotein cholesterol (HDL-C) (MD 3.28 mg/dL, 95% CI 0.66 to 5.90 mg/dL). Overall risk of bias was high, and certainty of evidence was very-low. Study limitations include the heterogeneity of intervention methods, in addition to small samples and short follow-ups, which undermine the effects of dietary intervention in metabolic parameters. CONCLUSIONS: Coconut oil intake revealed no clinically relevant improvement in lipid profile and body composition compared to other oils/fats. Strategies to advise the public on the consumption of other oils, not coconut oil, due to proven cardiometabolic benefits should be implemented. REGISTRATION: PROSPERO CRD42018081461.

Psychiatric profile and quality of life of subjects with excess weight treated with transcranial direct current stimulation combined with a hypocaloric diet.

Background: Transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) may reduce appetite and caloric intake and may be able to play a role as an adjunct treatment for obesity. Stimulation of this brain area is also used for the treatment of depression, which shares a common pathophysiology with obesity. As a result, the effect of tDCS on mental health and its impact on the quality of life of subjects with excess weight needs to be addressed.Objective: To assess the effect of daily tDCS of the right DLPFC on mood, daytime sleepiness, anxiety and quality of life in subjects with excess weight on a hypocaloric diet.Methods: We randomly assigned 28 subjects to receive 20 sessions of active or sham tDCS over the right DLPFC for 20 consecutive weekdays. The severity of depressive and anxiety symptoms was assessed by the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory-State (STAI-S). Sleepiness was measured by a daytime sleepiness questionnaire (DSQ), and quality of life was measured by the 36-Item Short Form Health Survey (SF-36).Results: There were no significant changes in BDI, STAI-S and DSQ scores between groups, even after adjustments for the use of antidepressant medications and changes in body weight. There were also no significant changes in different subscales of the SF-36 quality of life questionnaire between groups.Conclusion: Repetitive tDCS on the right DLPFC is not associated with impairment in mental health or quality of life in overweight and obese subjects.

The effect of transcranial direct current stimulation along with a hypocaloric diet on weight loss in excessive weight people: A pilot randomized clinical trial.

BACKGROUND & AIMS: The dorsolateral prefrontal cortex plays an important role in the desire to eat and food intake regulation and may be a target for transcranial direct current stimulation (tDCS) to promote weight loss. Our aim was to test the effect of repeated, active tDCS along with a hypocaloric diet (HD) on weight loss in overweight adults. METHODS: This was a randomized, placebo-controlled, double-blind pilot study conducted in Porto Alegre, Brazil. Twenty-eight overweight adults were selected to receive 4-week (20 sessions, t0 to t20; 5 weekdays) fixed-dose tDCS along with an HD. Subjects were randomly assigned to active (AG) or sham (SG) tDCS groups. The primary outcome was weight loss as determined via body weight measurements at baseline (t0), weekly (t5, t10, t15, and t20), and after the intervention (tF). A visual analogue scale was used to assess desire to eat at t0 and at tF. Registered under ClinicalTrials.gov Identifier no. NCT02683902. RESULTS: Although there was a greater weight loss in the AG (mean -4.5 kg [95%CI: -9.4, 0.5]) than in the SG (-2.3 kg [-5.0, 0.3]), this difference was not statistically significant. However, the AG showed a significant reduction in the desire for sweet foods (P = 0.005). CONCLUSIONS: Although this pilot study did not show that repeated tDCS is able to optimize weight loss, it was able to reduce the desire to eat sweet foods. These findings suggest that a protocol with a larger sample size could determine whether tDCS may be an adjunctive treatment of obesity.