Effect of a high monounsaturated fatty acids diet and a Mediterranean diet on serum lipids and insulin sensitivity in adults with mild abdominal obesity.

BACKGROUND AND AIMS: Diets high in monounsaturated fatty acids (MUFA) such as a Mediterranean diet may reduce the risk of cardiovascular diseases by improving insulin sensitivity and serum lipids. Besides being high in MUFA, a Mediterranean diet also contains abundant plant foods, moderate wine and low amounts of meat and dairy products, which may also play a role. We compared the effects of a high MUFA-diet with a diet high in saturated fatty acids (SFA) and the additional effect of a Mediterranean diet on insulin sensitivity and serum lipids. METHODS AND RESULTS: A randomized parallel controlled-feeding trial was performed, in 60 non-diabetics (40-65 y) with mild abdominal obesity. After a two week run-in diet high in SFA (19 energy-%), subjects were allocated to a high MUFA-diet (20 energy-%), a Mediterranean diet (MUFA 21 energy-%), or the high SFA-diet, for eight weeks. The high MUFA and the Mediterranean diet did not affect fasting insulin concentrations. The high MUFA-diet reduced total cholesterol (-0.41 mmol/L, 95% CI -0.74, -0.09) and LDL-cholesterol (-0.38 mmol/L, 95% CI -0.65, -0.11) compared with the high SFA-diet, but not triglyceride concentrations. The Mediterranean diet increased HDL-cholesterol concentrations (+0.09 mmol/L, 95% CI 0.0, 0.18) and reduced the ratio of total cholesterol/HDL-cholesterol (-0.39, 95% CI -0.62, -0.16) compared with the high MUFA-diet. CONCLUSION: Replacing a high SFA-diet with a high MUFA or a Mediterranean diet did not affect insulin sensitivity, but improved serum lipids. The Mediterranean diet was most effective, it reduced total and LDL-cholesterol, and also increased HDL-cholesterol and reduced total cholesterol/HDL-cholesterol ratio.

[The prevalence of the metabolic syndrome in the Netherlands: increased risk of cardiovascular diseases and diabetes mellitus type 2 in one quarter of persons under 60]. / De prevalentie van het metabool syndroom in Nederland: verhoogd risico op hart- en vaatziekten en diabetes mellitus type 2 bij een kwart van de personen jonger dan 60 jaar.

OBJECTIVE: To estimate the prevalence of the metabolic syndrome in the Netherlands in two populations in the age category 28-59 years and to compare this with the prevalence of hypercholesterolaemia in these populations. DESIGN: Descriptive. METHOD: Data from two Dutch population based studies were used: the 'Monitoring risicofactoren en gezondheid Nederland' (MORGEN) study ['Monitoring risk factors and health in the Netherlands' study] (1993-1995) and the 'Prevention of renal and vascular end-stage disease' (PREVEND) study (1998-1999). Subjects were identified as having the metabolic syndrome when they had at least three of the following five criteria according to the guideline of the 'National cholesterol education programme', 'Adult treatment panel III' (NCEP-2001): hyperglycaemia, low HDL-cholesterol level, hypertriglyceridaemia, hypertension or abdominal obesity. Final estimates were weighed according to the age- and sex distribution of the Dutch population during these survey years based on figures of the Dutch Central Bureau of Statistics. RESULTS: On average, the prevalence of the metabolic syndrome was 14%, 19% in men and 12% in women in the MORGEN study, and 16% and 10% in men and women in the PREVEND study. The prevalence in subjects below 40 was 12% for men and 5% for women. The prevalence increased considerably with age. Among subjects with both abdominal obesity and hypertension the prevalence was 68%. Among subjects with 'hypertriglyceridaemic waist' the prevalence was 94%. The prevalence of the metabolic syndrome showed little overlap with the prevalence of hypercholesterolaemia (> or = 6.5 mmol/l). In total, 26% of the subjects had either the metabolic syndrome or high total cholesterol levels. CONCLUSION: Approximately 1 million Dutch adults below 60 years of age had the metabolic syndrome in the 1990's. Based on the total prevalence of the metabolic syndrome and hypercholesterolaemia, one quarter of the Dutch population younger then 60 runs an increased risk of cardiovascular disease and type 2 diabetes mellitus.