Good News for Metabolic Syndrome

It’s January--a new beginning for a new year. And with every January comes a barrage of advertisements for new weight loss regimes, diets and exercise programs. Many of these strategies are supported by good science. Newly published research suggests that lifestyle counseling (LC), in combination with flaxseed and walnut supplementation, could be useful in the management of metabolic syndrome (MetS). Several metabolic abnormalities are involved in MetS including central obesity, dyslipidemia, elevated blood pressure, and hyperglycemia, which can lead to the enhanced development of type 2 diabetes and cardiovascular disease (CVD). In this interesting study published by investigators from the Chinese Academy of Sciences, Harvard School of Public Health, Fudan University, Shanghai University, the University of Alabama, Brigham and Women’s Hospital and Harvard Medical School, Wu and co-workers (2010) conducted a 3-arm, randomized, controlled trial. The 283 participants were screened for MetS using the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian-Americans. Participants were assigned to a LC on the AHA guidelines, LC + flaxseed (30g/d) (LCF), or LC + walnuts (30g/d) (LCW) group. The effects of all 3 interventions on MetS components, including central obesity, were assessed. Flaxseed was chosen, as it contains high amounts of polyunsaturated fatty acids (PUFA), mainly the omega-3, alpha-linolenic acid (ALA), as well as soluble fiber, lignan precursors and other antioxidants. Also a good source of both the omega-3 and omega-6 PUFAs, walnuts provide arginine (an amino acid with anti-hypertensive qualities) and fiber.

After the 12-week intervention, the prevalence of MetS decreased significantly in all groups: 216.9% (LC), 220.2% (LCF) and 216.0% (LCW). The reversion rate of MetS (i.e. those no longer meeting the MetS criteria at 12 weeks) was not significantly different among groups (LC group, 21.1%; LCF group, 26.6%; and LCW group, 25.5%). However, the reversion rate of central obesity was significantly higher in the LCF (19.2%) and LCW (16.0%) groups than in the LC group (6.3%). Most metabolic variables (weight, waist circumference, serum glucose, total cholesterol, LDL cholesterol, apolipoprotein (Apo) B, ApoE, and blood pressure) were significantly reduced from baseline in all 3 groups. Among participants with central obesity at baseline, flaxseed incorporation decreased fasting glucose and prevented an increase in HbA1c. The severity of MetS, assessed by the investigators as the mean count of MetS components, was significantly reduced in the LCW group compared with the LC group among participants with confirmed MetS at baseline.

Previous studies have shown that lifestyle modification, when combined with dietary change, plays an important role in controlling MetS. This is one of the first studies to show the effects of flaxseed and walnut supplementation in reducing central obesity, as well as the severity of MetS in a high-risk population. After the 12-week intervention, a 16.7% reduction of MetS was observed, prompting the authors to suggest “that a low-intensity LC program could be useful for MetS management.” And furthermore, “…participants in the LCF group showed a tendency to lose more weight than those in the LC group.” The data also indicated that “…LC plus flaxseed or walnuts may have additional benefits on central adiposity compared with LC only.” The authors postulated that the seed- and nut-derived dietary PUFA might serve as an important modulator for body fat deposition. In concluding, the investigators stated, “although flaxseed or walnut supplementation did not provide additional benefits on blood lipids, incorporating these foods into diets may improve central obesity status. Further studies with larger sample sizes and of longer duration are needed to examine the role of these foods in the prevention and management of MetS.”

Reference:

Wu H, et al.2010. Lifestyle Counselling and Supplementation with Flaxseed or Walnuts Influence the Management of Metabolic Syndrome. J Nutr. 140: 1937–1942.