Ingesta lipídica y Síndrome Metabólico en adultos con alto riesgo cardiovascular

Abstract

The Metabolic Syndrome (MetS) is a clinical condition characterized by a collection of metabolic factors associated with a higher risk of developing diabetes and cardiovascular disease (CVD). Such coexisting cardiometabolic risk factors include obesity (especially central obesity), insulin resistance, impaired glucose tolerance, atherogenic dyslipidaemia [high triglycerides levels (TG) and low levels of high-density lipoprotein (HDL-c)] and hypertension. Obesity, and consequently the MetS, are becoming an epidemic, as they are currently affecting approximately between 10-20% of adults worldwide. If such an epidemic continues to grow, up to 20% of the world's population is expected to be obese by 2030. Consistent with the latter, prevalence of the MetS will vary according to specific to population, age, gender, and ethnic origins, and the definition which might be used The use of dietary and lifestyle treatments for cardiometabolic disease prevention could be more effective than pharmacological therapy in preventing the development of the MetS. Accordingly, various studies have demonstrated that lifestyle modification, such as increased physical activity, adherence to a healthy dietary pattern and/or weight loss, are associated with the reversion of the MetS and its components. There is solid evidence that food intake is associated with the incidence of the MetS. High total fat and saturated fatty acids (SFA) intakes and an inadequate intake of fiber are closely linked to an unhealthy weight and/or to an increased risk of developing Type 2 Diabetes Mellitus (T2DM), which are also two of the main components of the MetS. In order to address the issue, scientific societies recommended a global limit to fat intake, which inevitably resulted in an increased consumption of carbohydrates and a reduced consumption of healthy unsaturated fatty acids. For this reason, in 2015, the Advisory Committee of the Dietary Guidelines for Americans emphasized the importance of food based dietary patterns, hence reconsidering the role of fat in health. Indeed, data from randomized controlled clinical trials does not support current dietary fat intake guidelines: dietary patterns such as the Mediterranean Diet (MedDiet), marked by high levels of vegetable fats, the Dietary Approaches to Stop Hypertension diet and vegetarian diets, have shown that MetS and its components are decreased in incidence and prevalence. Nevertheless, when it comes to describe the most appropriate dietary treatment for MetS, controversies and gaps of evidence still exists. For all the above reasons, the general purpose of this Doctoral Thesis is to compare fat intake in a population with and without MetS, to assess dietary intake and nutritional status in the MetS population and their possible association with the MetS components. The population of the study consists of adults, male between 55-75 years and women between 60-75 years, without previous CVD. The evidence collected demonstrates a significant association between fatty acids intakes and risk of developing the MetS. Subjects with MetS report lower intakes of fiber and carbohydrates, and a higher intake of fat as compared to subjects without MetS. More specific to the type of fat, subjects with MetS report a higher intake of monounsaturated fatty acids (MUFA) and a lower intake of polyunsaturated fatty acids (PUFA) ω-3 y ω-6 (women only) than subjects without MetS. On the other hand, no differences are observed in relation to SFA and trans fatty acids (Trans FA) (in men) intakes. Moreover, subjects with MetS are more likely to fall short of meeting the Acceptable Macronutrient Distribution Range proposed by the Institute of Medicine for carbohydrates and go above the recommended limits of total fat and MUFA, as compared to subjects without MetS. Results remain consistent when assessing the Nutritional Objective by 2020 of the Spanish Society of Community Nutrition. Both populations consume above the recommended intakes of Trans FA, fruits and vegetables, nevertheless consumption is higher in subjects with MetS. In relation to the association between the risk of prevalence of MetS components by fat intake, the results show a significant increase in the risk of hyperglycemia in subjects in the highest total fat intake, MUFA, SFA and PUFAω-3, a significant increase in the risk of presenting low levels of HDL-c in subjects with higher intakes of linoleic acid, and, on the other hand, a significant reduction in the risk of presenting high plasma TG levels in subjects with higher intakes of SFA and PUFA ω-3. However, no differences between Trans FA intakes and MetS components were observed. 82% of MetS subjects consume nuts, although the average daily intake is only 12.6 g/day. Subjects that consume dried nuts also have higher consumption of total energy, carbohydrates, total fat, MUFA and PUFA, cholesterol, fiber, vitamins and minerals than those that do not consume nuts. In turn, subjects that consume nuts are less likely to fall below the Acceptable Macronutrient Distribution Range and, at the same time, to exceed Adequate Intakes of most evaluated nutrients. Moreover, they are also more likely to have higher adherence to the MedDiet as compared to those that do not consume nuts. Finally, analysis at one-year follow-up of the population with MetS, show that with higher intake of nuts, waist circumference, plasma TG, systolic blood pressure, body weight, and Body Mass Index, are significantly reduced; concomitantly, there is a tendency for blood glucose and diastolic blood pressure to decrease, and HDL-c levels to increase. Dietary intake and nutritional status in adult subjects with MetS do not match dietetic recommendations for a healthy eating pattern. The present Thesis and the future work of intervention in the context of the PREDIMED-Plus trial will contribute to a better understanding of the role of fatty acids as part of the dietary approach used to reverse MetS-associated comorbidities in older individuals.