Effects of the intake of dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids in a sample of postmenopausal women with metabolic syndrome: a randomized, triple-blind, placebo-controlled clinical trial

Introduction: metabolic syndrome in postmenopausal women can improve with a healthy diet. Objectives: to evaluate whether a dietary intervention with dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids increases selenium plasma levels and improves cardiovascular risk factors in postmenopausal women with metabolic syndrome. Material and methods: a randomized, triple-blind, controlled clinical trial carried out in GP surgeries. Recruitment: April 2018, 46 postmenopausal women with metabolic syndrome who were frequent dairy consumers. Randomization: 23 in control group and 23 in experimental group. Intervention: consumption of dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids (milk, yogurt, fresh cheese) for three months. Controls took conventional dairy. Primary endpoint: plasma selenium levels; secondary endpoints: metabolic syndrome criteria. Registration number 2018/256, Galicia Ethics Committee. Results: in all, 23 women in the control group and 21 in the intervention group completed the trial. Selenium increased in the intervention group (7.2 µg/L, 95 % CI, 3.7/10.8) compared to the control group (-4.5 µg/L, 95 % CI, -8/-1) (p < 0.001) and very low-density lipoprotein cholesterol decreased (-2.3 mg/dL, 95 % CI, -5.6/1) compared to the control group (1.9 mg/dL, 95 % CI, -0.7/4.5) (p = 0.043). Waist circumference (p = 0.010), body mass index (p = 0.047) and high-density lipoprotein cholesterol (p < 0.001) in the experimental group improved in comparison to baseline measurements. Conclusions: an intervention with dairy products naturally enriched with selenium and omega-3 in a sample of postmenopausal women with metabolic syndrome can improve plasma selenium levels and very low-density lipoprotein cholesterol.