Effects of a Mediterranean-Style Diet on Cardiovascular Risk Factors

Abstract

Compared with a low-fat diet, Mediterranean diets supplemented with olive oil or nuts have beneficial effects on cardiovascular risk factors.

Health Benefits of Nut Consumption

“…A similar lack of weight gain was documented in the mostly overweight or obese participants in the PREDIMED study who consumed 30 g of mixed nuts per day during three months [80] and in overweight diabetics consuming 30 g of walnuts for six months in a study from Australia [94]. Recent evidence from the PREDIMED study shows a decreased prevalence of the metabolic syndrome, mainly due to reduced visceral adiposity, after intervention for 12 months in participants following a Mediterranean diet supplemented with 30 g of nuts per day [134].…”

“…A Mediterranean diet supplemented with 30 g of mixed nuts (walnuts, almonds and hazelnuts) per day also showed beneficial effects on the lipid profile compared with advice on a low-fat diet in diabetic and non diabetic participants in the PREDIMED study, a randomized trial of dietary intervention for the primary prevention of cardiovascular disease [80]. Of note, two randomized trials that used cashews or walnuts [81] and mixed nuts [82] compared to control diets in obese patients with the metabolic syndrome failed to show the predictable cholesterol lowering-effect, which supports the findings of the pooled analysis [69] (Figure 3) regarding the inverse association between cholesterol responses to nut feeding and BMI.…”

“…Two recent small studies, however, found reduced insulin levels in patients with metabolic syndrome [82] and diabetes [73] after nut feeding. The three-month report of the larger PREDIMED study [80] also showed that the Mediterranean diet enriched with nuts was associated with improved insulin sensitivity and fasting glucose levels in non diabetic and diabetic participants, respectively. Finally, two studies from the same group [99,100] reported reduced postprandial glucose and insulin excursions after almond meals compared with those elicited after meals containing carbohydrates with a high glycemic index.…”

“…Nevertheless, plasma levels of CRP, a standard measure of systemic low-grade inflammation, were usually unaffected in controlled feeding trials with almonds, walnuts, or mixed nuts, as reviewed up to 2008 [21]. On the other hand, other inflammatory mediators such as plasma levels of ICAM-1, vascular cell adhesion molecule [VCAM]-1, or IL-6 decreased after nut diets in two studies [80,113]. It must be noted that inflammatory biomarkers were always secondary outcomes of nut-feeding trials, thus problems of statistical power to detect significant changes are a problem.…”

“…This has not been observed in the usually small-sized clinical studies performed to date, but the larger PREDIMED trial did show significant reductions in both systolic and diastolic blood pressure after the nut-supplemented Mediterranean diet compared with the control diet [80]. A recent report of the PREDIMED trial provides an insight into the possible mechanism of this antihypertensive effect by showing that the nut diet was associated with reduced cholesterol: phospholipid ratios of erythrocyte membranes, which would translate into an increase of membrane fluidity [128].…”