Metabolic syndrome dietary therapy


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org]

Overview
Dietary modifications are the first step in treatment of metabolic syndrome. It can be started in isolation or along with other medications. It helps by assisting in weight loss, thus increasing insulin sensitivity. Studies support that diet, exercise, and drug therapy may inhibit the progression of metabolic syndrome to diabetes mellitus.

Dietary modifications
Findings from various studies suggest that:


 * Westernized and high fructose diets have increased risk for developing metabolic syndrome.


 * Mediterranean diet rich in fresh fruits, vegetables, whole grains, nuts, seeds, legumes, seafood, yogurt and olive oil lowers the risks for metabolic syndrome, ,.


 * The DASH (Dietary Approaches to Stop Hypertension) diet focusing on decreased sodium intake to 2400 mg/daily, when compared to a weight reducing diet, resulted in greater improvements in triglycerides, blood pressure, and fasting blood glucose.


 * Low carbohydrate diet has favorable effects on atherogenic dyslipidemia and glycemic control compared to a conventional diet at 6 months of follow up but no significant benefit at 1year was seen, , , . However, the supporting studies are small randomized trials (less than 150 patients). Thus, larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.


 * Some studies suggest that moderate red wine intake may protect against the development of metabolic syndrome . However, further supportive evidences are required.


 * Interestingly, in a meta-analysis chocolate was found to reduce the risks of coronary artery disease, cardiac deaths, diabetes, and stroke by approximately 30%. The possible explanation for this is the presence of polyphenols in chocolates that increases the concentration of nitric oxide (antioxidants).


 * Food with low glycemic index may be helpful in preventing metabolic syndrome and its complications. However, further supportive trials are required to prove this.

Trial supportive data
===Meta-analysis on effect of Mediterranean diet on metabolic syndrome ===


 * Source & year - J Am Coll Cardiol, 2011


 * Study question - Effect of a Mediterranean diet on metabolic syndrome and its components.


 * Study design – Meta-analysis


 * Study Population - {50 original research studies (35 clinical trials, 2 prospective and 13 cross-sectional), with 534,906 participants}


 * Study results -
 * Mediterranean diet was associated with reduced risk of metabolic syndrome (log hazard ratio: -0.69, 95% confidence interval [CI]: -1.24 to -1.16)


 * Also, statistically significant reduction in waist circumference, triglycerides, systolic and diastolic blood pressure and glucose was found. Additionally, an elevation of HDL cholesterol level was demonstrated.

===PREDIMED: Randomized controlled trial on effect of Mediterranean diet on metabolic syndrome ===


 * Source & year - Arch Intern Med. 2008


 * Study name - PREDIMED (Prevención con Dieta Mediterránea)


 * Study question – Determine the efficacy of the Mediterranean diet (Med-Diet) on the primary prevention of cardiovascular disease


 * Study design – Multicenter, 3-arm randomized controlled trial.


 * Study Population – 1224 participant


 * Study period – 1 year


 * Interventions - Quarterly education about the MedDiet + provision of either 1 L/wk of virgin olive oil or 30 g/d of mixed nuts, and advice on a low-fat diet (control diet).


 * Study results –


 * 61.4% of participants met criteria for the metabolic syndrome
 * 1 yr prevalence was reduced by 6.7%, 13.7%, and 2.0% in the MedDiet + virgin olive oil, MedDiet + nuts, and control diet groups, respectively
 * After adjustment for sex, age, baseline obesity status, and weight changes odds ratios for reversion of metabolic syndrome were
 * 1.3 (95% confidence interval, 0.8-2.1) for the MedDiet + virgin olive oil compared with control group.
 * 1.7 (1.1-2.6) for the MedDiet + nuts group compared with control group.

* Study conclusion - Mediterranean diet can be helpful in management of metabolic syndrome.