• Cardiometabolic Disorder
• Prevention & Screening
• Nutrition Physiology
• Obesity
• Assessment

• Cardiometabolic Disorder
• Prevention & Screening
• Endocrinology
• Diabetes & Metabolic Syndrome
• Nutrition Physiology
• Obesity
• Assessment

Epidemiologic data have shown that a Mediterranean diet that is low in saturated fat and high in polyunsaturated fats reduces low-density lipoprotein cholesterol and lowers the risk of cardiovascular events. Yet, the clinical evidence of benefit with the components of these diets is mixed, and was reviewed by Peter Clifton, MBBS, University of South Australia, Adelaide, Australia.

The Mediterranean diet recommends a low intake of saturated fats and high monounsaturated fats, with a low intake of meat and dairy, and high intake of fruits, vegetables, legumes, and nuts. Alcohol intake is modest.

Prof. Clifton discussed numerous studies that showed benefit of the Mediterranean diet and its components. Frequent nut consumption (>5 times/week) was associated with a 35% reduction in the incidence of coronary heart disease (CHD) in 4 epidemiological studies [Kris Etherton et al. J Nutr 2008]. In addition, a Mediterranean diet supplemented with extra virgin olive oil or nuts was associated with lower risk of CV events in the Prevención con Dieta Mediterránea (PREDIMED; Table 1) study [Estruch R et al. N Engl J Med 2013].

In the EPIC-NL cohort study of nearly 35,000 middle-aged persons without known CVD, a significant protective effect was found for each 2-point increment in the Mediterranean-style diet [Hoevenaar-Blom MP et al. PLoS One 2012]. The Spanish EPIC study showed that each 10 gram increase in olive oil consumption was associated with a 7% reduction in CHD [Buckland G et al. Br J Nutr 2012]. The Greek EPIC study found that each 2-unit increase in the Mediterranean diet score was associated with a 16% reduction in total mortality [Trichopoulou A et al. BMJ 2009].

Fruits and vegetables have been found to be associated with the same level of benefit in epidemiologic trials and are recommended as part of the DASH (Dietary Approaches to Stop Hypertension) diet for lowering blood pressure. However, there are no prospective clinical data showing that fruit and vegetable intake reduces CV events. Fish has been found to be associated with benefits in studies conducted in the United States, but this association has been less strong in Scandinavian studies. Recent intervention studies with fish oil have not found them to reduce CV events [The ORIGIN Trial Investigators. N Engl J Med 2012; de Caterina R et al. N Engl J Med 2011]. Meat and dairy products appear to be neutral or have mildly positive effects (dairy only). More data are required to identify the optimal level of salt intake. Some data have shown that limiting its intake is associated with a reduction in stroke and CV disease; however, increased salt intake can increase heart failure and may increase CV events in patients with diabetes.

RESHAPING NUTRITION HABITS IN CLINICAL PRACTICE

The public knows that a healthy diet is important for disease prevention, yet they are confused by the many different messages and changing research claims, said Benoît Lamarche, PhD, Université Laval, Québec City, Québec, Canada. Restrictive diets are difficult to sustain long-term and usually are most effective when coupled with support, which is usually short-term.

The 2010 United States Department of Agriculture dietary recommendations were useful because they moved from nutrient-based recommendations to food-based recommendations. More effective than restricting foods is adding foods or nutritional components that may be beneficial. This approach was studied in the PREDIMED study which showed the primary composite endpoint of myocardial infarction (MI), stroke, and CV death was reduced with the Mediterranean diet supplemented with extra virgin olive oil (HR, 0.70; 95% CI, 0.53 to 0.91; p=0.009) and with nuts (HR, 0.70; 95% CI, 0.53 to 0.94; p=0.02) [Estruch R et al. N Engl J Med, 2013].

A recent meta-analysis showed the Mediterranean diet is associated with positive effects (to different degrees) on metabolic syndrome and its components (Figure 2) [Kastorini CM et al. J Am Coll Cardiol 2011].

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Figure 2.

Effect of Mediterranean Diet on Metabolic Syndrome and Its Components in Meta-Analysis

DBP=diastolic blood pressure; HDL-C=high-density lipoprotein cholesterol; HOMA-IR=homeostatic model assessment of insulin resistance; SBP=systolic blood pressure; TG=triglycerides.Reproduced from Kastorini CM et al. The Effect of Mediterranean Diet on Metabolic Syndrome and its Components: A Meta-Analysis of 50 Studies and 534,906 Individuals. J Am Coll Cardiol 2011;57(11):1299–1313. With permission from Elsevier.

A series of studies by Richard, Lamarche, and colleagues have shown that the Mediterranean diet has beneficial effects whether or not patients also lose weight. LDL-C was reduced by 9.9% along with a significant reduction in plasma PCSK9 (by 11.7%; p<0.01) and the phytosterol:cholesterol ratio (by 9.7%; p<0.01) versus control diet, with no additional benefit with weight loss [Richard C et al. Br J Nutr 2012]. They also showed that adipokines were not reduced in patients who did not lose weight with the Mediterranean diet [Richard C et al. Metabolism 2013]. Inflammation was also reduced with the Mediterranean diet regardless of weight loss, as measured by C-reactive protein (CRP), interleukins, and other measures, and greater reductions in waist circumference in men were associated with greater reductions in inflammatory markers [Richard C et al. Obesity (Silver Spring) 2013].

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