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| Date: 03-31-2016 | HC# 031631-541 |
Zortea K, Franco VC, Francesconi LP, Cereser KMM, Lobato MIR, Belmonte-de-Abreu PS. Resveratrol supplementation in schizophrenia patients: a randomized clinical trial evaluating serum glucose and cardiovascular risk factors. Nutrients. January 29, 2016;8(2),73. doi: 10.3390/nu8020073.
Individuals with schizophrenia (SZ) are often overweight or obese, develop metabolic disorders, and have a reduced life expectancy, with cardiovascular disease (CVD) being the most common cause of mortality. Low-grade inflammation has been implicated as a contributing factor in the development of metabolic diseases including CVD. Some evidence suggests that resveratrol supplementation may aid in preventing metabolic diseases since the natural polyphenolic plant compound possesses cardioprotective, anticancer, and anti-inflammatory properties. These authors conducted a randomized, double-blind, placebo-controlled, clinical trial to determine the efficacy of resveratrol supplementation on serum glucose and CVD risk factors in patients with SZ.
The study was supported by Brazil's Public Health Service at the Schizophrenia Program of Hospital de Clinicas de Porto Alegre in Porto Alegre, Rio Grande do Sul, Brazil. Included in the study were 19 male patients with SZ as diagnosed by using the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition) Axis I Disorders. All patients had been on a stable dose of the antipsychotic drug clozapine for at least 6 months.
Ten patients were randomly assigned to the resveratrol (200 mg daily) group and 9 to the placebo (200 mg daily) group. The resveratrol (trans-resveratrol, 98% purified) and placebo (not described) supplements were obtained from a compounding pharmacy in Porto Alegre. The patients were instructed to take the first supplement after baseline measurements were conducted and to continue daily supplementation for 4 weeks; to maintain their usual diet and physical activity; and to abstain from foods containing substantial amounts of resveratrol. Study compliance was measured through weekly telephone calls and a pill count on day 30.
The patients received nutritional orientation, designed to reduce sugar and saturated fat intake and maintain regular consumption of fruits and vegetables, and instruction on maintaining a low-fat diet with a daily intake of 20-25 kcal/kg daily. A clinical evaluation at baseline and on day 30 determined anthropometric measurements, smoking status, amount of physical activity, fasting glucose levels, and lipid profile. Each patient was assessed by a trained psychologist using the Brief Psychiatric Rating Scale (BPRS) to determine psychopathology severity. At baseline, the patients were similar in all parameters. Mean age was 46.40 ± 11.18 years for those in the resveratrol group and 41.00 ± 7.87 years for those in the placebo group.
Reporting on the changes in clinical and biochemical parameters throughout the study, the authors write the "results show that the variables and markers examined were not significantly modified after resveratrol supplementation."
In the placebo group, the authors report a significant increase in total cholesterol (P=0.024) and low-density lipoprotein cholesterol (LDL-C; P=0.002), and a decrease in body fat percentage (P=0.038). Also seen in the placebo group were a nonsignificant reduction in high-density lipoprotein cholesterol and a nonsignificant increase in triglycerides. In the resveratrol group, a nonsignificant decrease of 7.64% was observed in triglyceride levels; nonsignificant increases were seen in total cholesterol (4.55%) and LDL-C (4.95%).
Pointing to the decreased body fat percentage in the placebo group, the authors state that at day 30, the group's dietary habits included 20% lower fat and cholesterol intake compared with baseline. An interesting finding, they say, is that despite the reduced dietary lipid intake in the placebo group, total cholesterol and LDL-C levels increased.
No significant changes were seen in serum glucose, anthropometric measures, medication dose, number of cigarettes smoked, exercise levels, symptoms, or diet intake in either group.
The authors also found positive correlations between the mean number of pills returned at day 30 in the resveratrol group (5) and the variations in waist circumference, conicity index (a measure of abdominal obesity), and body weight. In the placebo group, negative correlations were found between the mean number of pills returned (9) and the variations of waist circumference and conicity index.
Although in vitro and in vivo studies have reported resveratrol's beneficial effects on blood pressure, serum lipids, and glucose, placebo-controlled trials in humans have been varying and inconclusive.1,2
The authors suggest a few factors that may account for resveratrol's lack of efficacy, including too low of a dose and inadequate bioavailability. Additionally, they mention that the benefits seen with red wine consumption may be due to additional polyphenols in wine and not resveratrol alone. Also, in studies involving patients with psychiatric disorders, establishing good adherence to treatment is challenging.
In this study, resveratrol supplementation for 4 weeks did not change the variables and markers examined, including body weight, waist circumference, glucose, and total cholesterol. Noting that the lipid profile in the placebo group worsened, the authors state, "We can assume that resveratrol might prevent lipid profile damage and that the intervention affected the lipoprotein metabolism at various levels." Future studies warrant exploration with larger population sizes, longer treatment periods, and increased doses of resveratrol.
―Shari Henson
References
1de Ligt M, Timmers S, Schrauwen P. Resveratrol and obesity: can resveratrol relieve metabolic disturbances? Biochim Biophys Acta. 2015;1852(6):1137-1144.
2Tomé-Carneiro J, Larrosa M, González-Sarrías A, Tomás-Barberán FA, García-Conesa MT, Espín JC. Resveratrol and clinical trials: the crossroad from in vitro studies to human evidence. Curr Pharm Des. 2013;19(34):6064-6093.
