Prevention of Cardiovascular Disease With Med or Veg Diets
Condition: Cardiovascular Disease
MeSH terms: Cardiovascular Diseases
Study type: Interventional

Summary: 
      The study is a randomized, open, cross-over trial designed to test whether a vegetarian diet
      would benefit the cardiovascular risk profile of the participants, compared with a
      Mediterranean diet.
    

Detailed description: 
      Nutrition is able to substantially alter the health status of the general population. In
      industrialized countries such as Italy the most important association between diet and health
      is certainly the relationship with cardiovascular disease, the leading cause of death and
      disability. The ability to identify with certainty, therefore, the relationship between diet
      and cardiovascular disease appears to be a key element in the implementation of specific
      primary prevention strategies.

      Cardiovascular diseases would be the result of interactions between genetics and
      environmental factors. Many studies have evaluated the associations between food groups,
      foods, or nutrients and chronic diseases, and a consensus about the role of nutritional
      factors in the etiology of common diseases, such as cardiovascular and neoplastic diseases,
      has gradually emerged. Recent studies have been focused on examining the impact of a whole
      dietary approach rather than on isolating single nutrients; it is recognized that analyses of
      single nutrients ignore the important and complex interactions between components of a diet
      and, more importantly, because people do not eat isolated nutrients.

      The optimal dietary strategy for the prevention of chronic degenerative diseases remains a
      challenging and a highly relevant preventive health issue. Over the last years, numerous
      evidence on the existing relationship between nutrition and chronic degenerative diseases
      have led investigators to search for the optimal dietary pattern to maintain a good health
      status. Several models of diet have been imposed on public attention, but those that got the
      most interest are certainly Mediterranean and vegetarian diets. These dietary patterns seem
      to exert protective effects on blood pressure, lipid profiles, cardiovascular diseases and
      metabolic parameters.

      The term Mediterranean diet has been widely used to describe the traditional dietary habits
      of people in Crete, South Italy, and other Mediterranean countries during the decade of the
      1960s. Since the first data from the Seven Countries Study, several studies in different
      populations have established a beneficial role for the main components of the Mediterranean
      diet on the occurrence of cardiovascular diseases and chronic degenerative diseases. This
      dietary pattern is characterized by plentiful plant foods (fruits, vegetables, breads, other
      forms of cereals, beans, nuts, and seeds), olive oil as the principal source of fat, moderate
      amounts of dairy products (mainly cheese and yogurt), low to moderate amounts of fish and
      poultry, red meat in low amounts and wine consumed in low to moderate quantities, usually
      with meals.

      The vegetarian diet is a diet that excludes the use of animal foods (meat, fish) in its
      fresh, preserved and/or processed. The increase in the number of vegetarians is attributable
      to health, ethical, environmental, and social concerns.

      Recently, meta-analysis conducted by our group have revealed, in a population of over than 2
      million of people, that a strict adherence to a Mediterranean dietary pattern is associated
      with a significant improvement in health status, as seen by a significant reduction in
      overall mortality (10%) and incidence and/or mortality from cardiovascular diseases (9%).

      During the past few decades, there has been a gradual abandonment of this dietary pattern by
      the inhabitants of the Mediterranean basin, especially by the younger generations. Several
      factors have contributed to this nutrition transition, such as the enhanced commercial
      availability of food, the urbanization of life, and the overall improvement in socioeconomic
      conditions in Europe, which has increased the food and energy supply and made food
      (especially of animal origin) more affordable. Consumption of milk, meat and animal fat
      products increased in all Mediterranean countries. Moreover, a stressful lifestyle, less time
      spent on cooking, and the enhanced variety and availability of household appliances have also
      been proposed as determinants of nutrition transition.

      Because of the growing evidence in favor of link between red and processed meat and
      cardiovascular disease risk, cancer and diabetes, the interest towards vegetarian diets has
      increased. In the last years, the number of subjects who began to adopt a vegetarian dietary
      pattern has enormously increased with respect to the past, when the population of vegetarians
      was limited only to few and selected cohorts. Such increase has been mainly attributed to the
      supposed beneficial effect of this dietary pattern versus the occurrence of diseases.

      Health benefits of Mediterranean and vegetarian diets have been widely described in
      case-control and prospective cohort studies during the last 50 years. There are several
      beneficial nutrients that are abundant in these diets, such as monounsaturated fatty acids,
      high amounts of fiber and antioxidants and low intake of total and saturated fats. However,
      it is unclear whether established health benefits for vegetarians are attributable to the
      absence of meat in the diet, the increased consumption of particular food component(s) the
      pattern of foods eaten within the vegetarian diet or other healthy lifestyle components often
      associated with vegetarianism.

      In a recent systematic review with meta-analysis carried out on over than 130,000
      vegetarians, plant-based diet was associated with many health benefits. Main findings were
      that vegetarian diet determines, among case-control studies, lower levels of the most
      important risk factor for chronic disease, along with a reduced risk of occurrence for
      ischemic heart disease (-25%) when cohort prospective studies were taken into account.

      Currently there are no randomized controlled trials to compare, in a high-risk group of
      patients with risk factors for cardiovascular disease, the efficacy of nutritional
      interventions based on Mediterranean and vegetarian dietary patterns. From this comparison it
      would may be possible to obtain interesting results in order to identify the optimal diet for
      prevention of cardiovascular diseases.

      OBJECTIVES:

      The primary aim of the study is to compare the effects of vegetarian diet on risk markers
      (anthropometric and biochemical measures) associated with cardio-metabolic diseases (CMD)
      after a 3-month dietary-intervention phase, compared with a Mediterranean diet.

      Secondary objectives of the study are:

        -  To improve knowledge about the pathophysiological role of vegetarian and Mediterranean
           diets in cardiovascular prevention

        -  To evaluate the feasibility and degree of adherence to a dietary substitution with
           vegetarian diet in a omnivorous population

        -  To evaluate the ability of a nutrition education intervention to reduce fresh and
           processed meat consumption in subjects at high cardiovascular risk, in order to enhance
           health and quality of life

        -  To explore the impact of food prices on consumption and to evaluate the overall cost of
           buying food products in different dietary patterns

      STUDY DESIGN The study is a randomized, open, cross-over trial designed to test whether a
      vegetarian diet would benefit the cardiovascular risk profile of the participants, compared
      with a Mediterranean diet.

      The eligible participants are randomly divided into two groups, each assigned to either the
      experimental group (Group 1), which receives a vegetarian diet, or the control group (Group
      2), which receives a Mediterranean diet. Following the first intervention phase, the subjects
      are crossed over in order to obtain the second intervention phase. Both diets are isocaloric
      and lasting three months each. The whole trial includes five clinical visits.

      STUDY POPULATION Subjects in primary prevention with low-middle cardiovascular risk (1-5%
      according to the guidelines of the European Society of Cardiology), determined by the
      presence of BMI >o=25 kg/m2 and no more than other 2 concomitant metabolic risk factors.
    

Intervention name(s): Vegetarian diet; Mediterranean diet
Intervention type(s): Other; Other
Intervention description(s): 7-days dietary profile with an isocaloric Vegetarian diet for 3 months; 7-days dietary profile with an isocaloric Mediterranean diet for 3 months
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: diet; vegetarian; cardiovascular risk