A new role for diet in reducing the incidence of cardiovascular disease: evidence from recent studies

Quality, but not cost, of diet is associated with 5-year incidence of CVD: the ATTICA study

OBJECTIVE

The aim of the present work was to calculate the current cost of the Mediterranean diet in Greece and to evaluate the role of diet cost in the development of cardiovascular events after a 5-year follow-up.

DESIGN

Cross-sectional. Cost of diet was measured in €/week based on common Greek dietary choices, while baseline dietary habits were assessed through a semi-quantitative FFQ (Greek-EPIC). The Mediterranean Diet Score (MedDietScore) was applied to assess overall adherence to this pattern using scores of eleven food variables and alcohol, according to the principles of the Mediterranean diet.

SETTING

Five-year follow-up of the ATTICA study, a nutrition and health survey of a representative, free-living sample of the Greek population resident in the province of Attica, where Athens is a major metropolis.

SUBJECTS

From 2001 to 2002, 1514 men and 1528 women (aged >18 years) without known CVD were enrolled. In 2006, the 5-year follow-up was performed.

RESULTS

The weekly cost of participants' diets varied from 5·35 to 83·57 €/week in men (mean 25·45 (sd 6·80) €/week) and from 10·89 to 55·49 €/week in women (mean 25·63 (sd 6·30) €/week). Diet cost was correlated marginally to MedDietScore (r = 0·060, P = 0·05) as well as being associated with history of hypercholesterolaemia (mean (sd), yes v. no: 24·90 (5·73) v. 25·82 (6·95) €/week, P = 0·027), physical activity (mean (sd), yes v. no: 26·42 (6·90) v. 24·82 (6·20) €/week, P < 0·001) and current smoking (mean (sd), yes v. no: 24·99 (6·40) v. 25·98 (6·70) €/week, P = 0·017). No significant association was found between diet cost and 5-year incidence of CVD (hazard ratio = 1·021, 95 % CI 0·965, 1·081). However, adherence to the traditional Mediterranean diet was inversely associated with the development of CVD (relative risk per 1-unit increase in MedDietScore = 0·92, 95 % CI 0·89, 0·94) after adjustment for various potential confounders including diet cost.

CONCLUSIONS

Quality but not cost of the diet is associated with the development of CVD.

Olive oil and the haemostatic system

Interest in the Mediterranean diet (MD) has grown worldwide due to its link with greater longevity and lower cardiovascular disease rate, cancer and age cognitive decline. Despite the high complexity of its nutrients composition, olive oil emerges as its principal food, since it provides the higher percent of energy and a lot of bioactive compounds. In this review we will discuss the benefits of diets enriched in virgin olive oil, whose effects are probably due not only to its oleic acid content but also to its other potentially health-promoting components. Traditionally, the benefits of MD were linked to its effect on lipoprotein metabolism but today we realise that there exists a whole sheaf of other benefits, including the components of haemostasis: platelet function, thrombogenesis and fibrinolysis. A diet enriched in virgin olive oil can reduce the sensitivity of platelets to aggregation, decreasing von Willebrand and tromboxane B2 plasma levels. Moreover a particular interest has arisen about its capacity to decrease fasting Factor VII plasma levels and to avoid or modulate its postprandial activation. Also Tissue Factor expression in mononuclear cells could be reduced with the chronic intake of virgin olive oil and finally, studies performed in different experimental situation have shown that it could also increase fibrinolytic activity, reducing plasma concentration of Plasma Activator Inhibitor type-1.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

Antioxidative properties of brown algae polyphenolics and their perspectives as chemopreventive agents against vascular risk factors

Several polyphenolic compounds and complex mixtures were isolated from brown algae species. The 1,1-diphenyl-2-picryhydarzyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) of these compounds were evaluated to determine their physiological usefulness as antioxidants for vascular protection. The antioxidative protection of low-density lipoprotein (LDL) was also evaluated and compared with that of catechin, because the generation of oxidized LDL is one of the most active and specific risk factors contributing to atherogenesis. Oral administration to rats of a commercially available sample (VNP) containing 30% of these polyphenolic compounds and 70% dietary fiber revealed that the serum reducing capacity measured in terms of FRAP value was significantly elevated 30 min after the treatment, but declined rather quickly thereafter, indicating the good oral absorption of the compounds and their fast binding to the lumenal surface of the blood vessels. An eight-week, human, clinical trial (n=31) of VNP showed significant improvement in erectile function measured by IIEF (international index of erectile function) score. These results collectively demonstrated the usefulness of these polyphenolic compounds as fundamental chemopreventive agents against vascular risk factors originating from oxidative stress.

Food products containing free tall oil-based phytosterols and oat beta-glucan lower serum total and LDL cholesterol in hypercholesterolemic adults

This randomized, double-blind, controlled trial evaluated the influence of low fat, low saturated fat food products that contained free tall oil-based phytosterols (TOP) and oat beta-glucan (from whole oats and bran concentrate) on serum lipid concentrations in adults with mild-to-moderate hypercholesterolemia. After a 5-wk National Cholesterol Education Program Step I diet lead-in period, 112 subjects incorporated one of two treatments into their diets for 6 wk: food products (cereal, snack bar and beverage) that provided 1.8 g TOP and 2.8 g beta-glucan/d and contained < or =3.0 g total fat and < or =1.0 g saturated fat (TOP/beta-glucan treatment) or similar control foods. The serum LDL cholesterol response from baseline to the end of study was significantly larger in the TOP/beta-glucan treated group than in the control group, in which there was no change (-3.7 vs. 0.4%; P = 0.013). Likewise, total cholesterol decreased in the TOP/beta-glucan treatment group and did not change significantly in the controls (-2.3 vs. 0.8%; P = 0.043). Serum HDL cholesterol and triglyceride responses did not differ between the groups. The results of this trial suggest that consumption of a group of low fat, TOP and beta-glucan- containing foods is a useful adjunct in the dietary management of hypercholesterolemia.