A Randomized Trial with Two Hypocaloric Diets with Different Lipid Profiles and Effects on Serum Omentin-1 Levels in Obese Subjects

BACKGROUND: The effects of weight loss therapies on omentin-1 levels have been unclear, showing both elevations and decreases in circulating levels. The role of dietary fat might have an important role. The aim of our investigation was to evaluate the influence of weight decrease on omentin-1 levels after two different high-fat hypocaloric diets. METHODS: 319 Caucasian obese subjects were randomly allocated during 12 weeks (Diet M (high monounsaturated fat diet) vs. Diet P (high polyunsaturated fat diet)). The mean age was 47.2 ± 5.0 years (range: 26-64), and the mean body mass index (BMI) was 37.9 ± 4.1 kg/m(2) (range: 30.6-39.8). Sex distribution was 237 females (74.7%) and 72 males (25.3%). Anthropometric and biochemical parameters were evaluated at basal and after both diets. SPSS 23.0 has been used to realize univariant and multivariant statistical analysis. RESULTS: After both diets, BMI, weight, fat mass, waist circumference, systolic blood, LDL-cholesterol, insulin levels, and HOMA-IR decreased in a statistical way from basal values. These improvements were similar in both diets. After Diet P, omentin-1 levels increase (21.2 ± 9.1 ng/ml: P = 0.02), and after Diet M, this adipokine increases (47.1 ± 11.2 ng/ml: P = 0.02), too. The increase of omentin-1 with Diet M was statistically significantly higher than that after Diet P (P = 0.01). A multiple regression analyses adjusted by age and sex reported a statistical relation between BMI (kg/m(2)) and insulin (UI/L) with omentin-1 levels. CONCLUSIONS: Our study demonstrated a significant improvement on serum omentin-1 levels after weight loss secondary to both diets; in contrast, omentin-1 improvement was higher with Diet M than with Diet P.