Effects of a Mediterranean-inspired diet on blood lipids, vascular function and oxidative stress in healthy subjects

Abstract

Mediterranean-inspired diets have been shown to decrease cholesterol levels in patients with hypercholesterolaemia, who frequently exhibit endothelial dysfunction. The aims of the present study are to improve endothelial function by dietary intervention in healthy subjects with lipid levels representative of a Western population. Twenty-two healthy subjects (mean total cholesterol, 5.6 mmol/l) were given a Mediterranean-inspired diet rich in omega-3 fatty acids and sterol esters, but low in saturated fat, or an ordinary Swedish diet, for 4 weeks in a randomized cross-over study. The composition of the diets were: in the Swedish diet, 2090 kcal (where 1 kcal=4.184 kJ; 48% of energy from carbohydrate, 15% from protein and 36% from fat) and 19 g of fibre; in the Mediterranean-inspired diet, 1869 kcal (48% of energy from carbohydrate, 16% from protein, 34% from fat) and 40 g of fibre. After each dietary period, fasting blood lipids, insulin and glucose levels, as well as apo B (apolipoprotein B) and LDL (low-density lipoprotein) particle size, were analysed. Endothelial-dependent and -independent vasodilation was measured invasively by venous occlusion plethysmography, and arterial distensibility was assessed by echocardiography tracking. Fibrinolytic capacity across the forearm, as well as oxidative stress measured through urinary F(2)-isoprostane, were evaluated. Total, LDL- and apo B-cholesterol and triacylglycerol (triglyceride) concentrations were decreased by 17%, 22%, 16% and 17% respectively, after the Mediterranean-inspired diet compared with the Swedish diet ( P <0.05 for all). However, no differences in plasma concentrations of insulin and glucose and LDL particle size, endothelial function, arterial distensibility, fibrinolytic capacity or oxidative stress were detected. Treatment for 4 weeks with a Mediterranean-inspired diet decreased blood lipids in healthy individuals with a low-risk profile for cardiovascular disease. This beneficial effect was not mirrored in vascular function or oxidative stress evaluation.

A 3 years follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain

“…There are short-term interventional studies analyzing the effects of the Mediterranean diet on circulating oxidative stress biomarkers, but not measuring the TAC (Hagfors et al, 2003;Ambring et al, 2004;Zulet et al, 2008;Puchau et al, 2009). Moreover, this study goes further and analyzes the influence of this antioxidant capacity of the three nutritional interventions on adiposity indexes.…”

“…There are also short-term interventional studies analyzing the Mediterranean diet and its potential association with other oxidative stress biomarkers (Hagfors et al, 2003;Ambring et al, 2004), but there are not long-term interventional studies about this issue. Our study is a 3-year randomized trial that supports the idea that a greater adherence to Mediterranean diet is associated with higher plasma antioxidant capacity (Pitsavos et al, 2005;Dai et al, 2008).…”

The effects of a high-fruit and -vegetable, high-fiber, low-fat dietary intervention on serum concentrations of insulin, glucose, IGF-I and IGFBP-3

“…It is possible that glucose is simply more sensitive to dietary change in general than is insulin. In a wide range of intervention studies testing the effects of a variety of dietary interventions (including low-fat diets, low-glycemic index diets, the DASH diet, Mediterranean diet, high-fiber diets and diets that substitute mono-unsaturated fat in place of saturated fat), it was frequently the case that if the investigators observed any changes, they observed decreases in glucose concentration but no change in insulin concentration (Fukagawa et al, 1990;Landin et al, 1992;Straznicky et al, 1999;Bisschop et al, 2001;Bouche et al, 2002;Miller et al, 2002;Hall et al, 2003;Juntunen et al, 2003;Kaaks et al, 2003;Ambring et al, 2004;Heald et al, 2004;Sloth et al, 2004). Our results are consistent with these findings.…”

“…Results from 12 dietary intervention studies in normal-weight, healthy individuals were somewhat mixed with many, but not all, showing modest reductions in fasting glucose concentration after the intervention but little change in insulin. These studies, however, were generally small (only one study enrolled as many as 100 subjects, with over half enrolling fewer than 25), used interventions of brief duration (interventions were longer than 12 weeks in only two studies and never longer than 6 months) and frequently involved significant weight change (Fukagawa et al, 1990;Landin et al, 1992;Straznicky et al, 1999;Bisschop et al, 2001;Bouche et al, 2002;Miller et al, 2002;Hall et al, 2003;Juntunen et al, 2003;Kaaks et al, 2003;Ambring et al, 2004;Heald et al, 2004;Sloth et al, 2004).…”

Session 4: CVD, diabetes and cancer Evidence for the use of the Mediterranean diet in patients with CHD

“…The observed lowering of plasma cholesterol was reported to indicate a potential 9% reduction in cardiovascular risk in the low-fat diet group compared with 15% in the Mediterranean diet group (125) . Other intervention studies have also demonstrated a beneficial lipid-altering effect (126,127) , including HDL-raising effects (48,115) . Mediterranean diet and body weight and blood pressure.…”