Origen, componentes y posibles mecanismos de acción de la dieta mediterránea / Origin, components and mechanisms of action of the Mediterranean diet

The Mediterranean diet is currently considered a healthy dietary pattern. It includes a great variety of foods, which are eaten in moderation and within a positive social environment. The generic term “Mediterranean diet” was born after the “Seven Countries Study” led by Ancel Keys around 1960. This dietary pattern is characterized by a high intake of fruits and vegetables, whole grains, legumes, nuts, fish, white meats and olive oil. It also includes moderate consumption of fermented dairy products, low intake of red meat and drinking wine with moderation during meals. Nutritionally, this diet is low in saturated fats and animal protein, high in antioxidants, fiber and monounsaturated fats, and exhibits an adequate omega-6/omega-3 fatty acid balance. The main bioactive compounds, which explain the health benefits of this dietary pattern, are antioxidants, fiber, monounsaturated and omega-3 fatty acids, phytosterols and probiotics. This diet is not exclusively confined to the Mediterranean Basin. Central Chile has a Mediterranean climate and our agriculture and culinary traditions are similar to those found in Mediterranean countries. Therefore, it is fundamental to increase awareness about the richness of our natural produce as well as our culinary culture, which may bring many health benefits and improve the quality of life in our population.

Validación de cuestionario autoaplicable para un índice de alimentación mediterránea en Chile / Validation of self-applicable questionnaire for a Mediterranean dietary index in Chile

Background: Availability of brief dietary indexes that can effectively evaluate dietary patterns and their association with health is critical for prevention and management of several chronic disease conditions. Aim: To adapt a self-applicable Mediterranean Dietary Index in Chile (Chilean-MDI). Material and Methods: The Chilean-MDI was developed based on a previous Mediterranean eating score that was adapted to Chilean dietary habits. This index was further validated in a sample of 153 adults by comparing the concordance between the results obtained by self-application of the Chilean-MDI with those obtained by a trained nutritionist. Additionally, the index was applied in a sample of 53,366 Chilean adults in order to describe the diet quality of our population. Results: There was an adequate concordance between findings obtained by self-application of the Chilean-MDI and those achieved by the nutritionist. The application of the index in Chilean adult population showed a better diet quality (high Mediterranean diet adherence) among women, with advanced age and among people with higher educational levels. Conclusions: The Chilean-MDI can be successfully self-applied to portray the overall diet quality in the Chilean adult population. Additionally, this dietary index describes overall food intake in Chilean adults, showing demographic trends that are comparable to those obtained with similar indexes applied in other populations.

Evidencia actual sobre los beneficios de la dieta mediterránea en salud / Current evidence on health benefits of the mediterranean diet

The Mediterranean diet is currently considered a functional diet with an increasing amount of scientific evidence that supports its beneficial effects in human health. Several observational cross-sectional and prospective cohort studies show an association between this diet and a lower prevalence and incidence of chronic diseases, such as cardiovascular disease, cancer, metabolic syndrome, diabetes, and neurodegenerative diseases as well as a reduced overall mortality. Additionally, clinical interventional studies, particularly the PREDIMED (Prevención con Dieta Mediterránea) initiative, have shown, with high quality scientific evidence, that a Mediterranean diet -supplemented either with olive oil or nuts- can lower by 30% the incidence of cardiovascular disease, reverse the metabolic syndrome, and prevent the development of diabetes and aging-related cognitive decline. Chile has one of the five Mediterranean ecosystems in the world, and therefore the implementation of this food pattern and lifestyle in our country may determine large benefits to the health status and quality of life in the Chilean population.

Antioxidant and anti hyperglycemic role of wine grape powder in rats fed with a high fructose diet

BACKGROUND: Metabolic syndrome is a growing worldwide health problem. We evaluated the effects of wine grape powder (WGP), rich in antioxidants and fiber, in a rat model of metabolic syndrome induced by a high fructose diet. We tested whether WGP supplementation may prevent glucose intolerance and decrease oxidative stress in rats fed with a high fructose diet. METHODS: Male Sprague-Dawley rats weighing 180 g were divided into four groups according to their feeding protocols. Rats were fed with control diet (C), control plus 20 % WGP (C + WGP), 50 % high fructose (HF) or 50 % fructose plus 20 % WGP (HF + WGP) for 16 weeks. Blood glucose, insulin and triglycerides, weight, and arterial blood pressure were measured. Homeostasis model assessment (HOMA) index was calculated using insulin and glucose values. A glucose tolerance test was performed 2 days before the end of the experiment. As an index of oxidative stress, thio-barbituric acid reactive substances (TBARS) level was measured in plasma and kidney, and superoxide dismutase was measured in the kidney. RESULTS: Thiobarbituric acid reactive substances in plasma and renal tissue were significantly higher when compared to the control group. In addition, the area under the curve of the glucose tolerance test was higher in HF fed animals. Furthermore, fasting blood glucose, plasma insulin levels, and the HOMA index, were also increased. WGP supplementation prevented these alterations in rats fed with the HF diet. We did not find any significant difference in body weight or systolic blood pressure in any of the groups. CONCLUSIONS: Our results show that WGP supplementation prevented hyperglycemia, insulin resistance and reduced oxidative stress in rats fed with HF diet. We propose that WGP may be used as a supplement in human food as well.

Wine grape pomace flour improves blood pressure, fasting glucose and protein damage in humans: a randomized controlled trial

BACKGROUND: The Mediterranean diet is a healthy diet with positive scientific evidence of preventing chronic diseases. Bioactive components support the healthy properties of the Mediterranean diet. Antioxidants and fiber, two components of the Mediterranean diet, are key functional nutrients for healthy eating and nutrition. Wine grape pomace is a rich source of these dietary constituents and may be beneficial for human health. Our hypothesis was that the intake of red wine grape pomace flour (WGPF) prepared from red wine grapes (Cabernet Sauvignon variety) reduced the metabolic syndrome in humans. To evaluate the effect of WGPF on components of metabolic syndrome we design a 16-week longitudinal intervention study. Thirty-eight males, 30-65 years of age, with at least one component of metabolic syndrome, were randomly assigned to either the intervention group (n = 25) or the control group (n = 13). At lunch, the intervention group was given 20 g of WGPF per day, which contained 10 g of dietary fiber, 822 mg of polyphenols and an antioxidant capacity of 7258 ORAC units. Both groups were asked to maintain their regular eating habits and lifestyles. Clinical evaluation, anthropometric measurements and biochemical blood analyses were done at the beginning and the end of the study. RESULTS: WGPF intake significantly decreased systolic and diastolic blood pressure as well as fasting glucose levels. Plasma γ-tocopherol and δ-tocopherol increased and carbonyl group in plasma protein decreased in WGPT group, significantly. No significant effect was observed for waist circumference, HDL cholesterol, triglycerides, total antioxidant capacity and vitamin C in and between groups. The group-dependent magnitude of the differences between the baseline and final postprandial insulin values and γ-tocopherol concentrations was statistically significant. CONCLUSIONS: The consumption of WGPF-rich in fiber and polyphenol antioxidants, as a food supplement in a regular diet improves blood pressure, glycaemia and postprandial insulin. In addition, increased antioxidant defenses and decreased oxidative protein damage indicating attenuation of oxidative stress. WGPF might be a useful food ingredient for health promotion and chronic disease prevention.

Effect of mediterranean and occidental diets, and red wine, on plasma fatty acids in humans: an intervention study

The type of diet consumed by individuals has been associated with the development of some chronic diseases, including cardiovascular disease (CVD), cancer, diabetes, and others. Populations that consume diets rich in fruits and vegetables and drink wine in moderation, as the Mediterranean, have a higher life expectancy and less chronic diseases than other occidental populations. We carried out an intervention study in humans to evaluate the effect of a Mediterranean diet (MD), an Occidental diet (OD) and their supplementation with red wine, on biochemical, physiological and clinical parameters related to atherosclerosis and other chronic diseases. For 3 months, two groups of 21 male volunteers each, received either a MD or an OD; during the second month, red wine was added isocalorically, 240 ml/day. At days 0, 30, 60 and 90, clinical, physiological and biochemical evaluations were made. In this article we report on the results obtained in plasma fatty acids profile that includes saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), ómega-6 fatty acids, ómega-3 fatty acids and ómega-6/ómega-3 ratio. Other results have been published previously. Plasma fatty acid percentages in the OD group, compared to the MD group, did not show differences in SFA, but the OD group showed lower levels of MUFA and ómega-3 fatty acids, and higher levels of PUFA and ómega-6 fatty acids, with a higher ómega-6/ómega-3 ratio than the MD group. Wine supplementation reduced MUFA and increased PUFA in both dietary groups, suggesting that wine could improve a diet with a good ómega-6/ómega-3 ratio. Volunteers on MD showed a better fatty acid profile than those on OD, suggesting a lower cardiovascular risk. Moderate consumption of wine improves this profile in the MD group.