Reduction in the Incidence of Type 2 Diabetes With the Mediterranean Diet

Abstract

OBJECTIVETo test the effects of two Mediterranean diet (MedDiet) interventions versus a low-fat diet on incidence of diabetes.RESEARCH DESIGN AND METHODSThis was a three-arm randomized trial in 418 nondiabetic subjects aged 55–80 years recruited in one center (PREDIMED-Reus, northeastern Spain) of the Prevención con Dieta Mediterránea [PREDIMED] study, a large nutrition intervention trial for primary cardiovascular prevention in individuals at high cardiovascular risk. Participants were randomly assigned to education on a low-fat diet (control group) or to one of two MedDiets, supplemented with either free virgin olive oil (1 liter/week) or nuts (30 g/day). Diets were ad libitum, and no advice on physical activity was given. The main outcome was diabetes incidence diagnosed by the 2009 American Diabetes Association criteria.RESULTSAfter a median follow-up of 4.0 years, diabetes incidence was 10.1% (95% CI 5.1–15.1), 11.0% (5.9–16.1), and 17.9% (11.4–24.4) in the MedDiet with olive oil group, the MedDiet with nuts group, and the control group, respectively. Multivariable adjusted hazard ratios of diabetes were 0.49 (0.25–0.97) and 0.48 (0.24–0.96) in the MedDiet supplemented with olive oil and nuts groups, respectively, compared with the control group. When the two MedDiet groups were pooled and compared with the control group, diabetes incidence was reduced by 52% (27–86). In all study arms, increased adherence to the MedDiet was inversely associated with diabetes incidence. Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity.CONCLUSIONSMedDiets without calorie restriction seem to be effective in the prevention of diabetes in subjects at high cardiovascular risk.

Nut consumption for vascular health and cognitive function

“…The effects of nuts on insulin sensitivity are influenced strongly by changes in body weight, which may have accounted for the changes observed in one of these studies where participants reduced body weight with nut consumption. Longer intervention trials with Mediterranean diets supplemented daily with 20-50 g of walnuts or 30 g of mixed nuts (a mixture of walnuts, almonds and hazelnuts was used in the PREvencion con DIeta MEDiterranea (PREDIMED) trial as reported by Casas-Agustench et al (21) ) resulted in a reduction in fasting glucose, insulin and improvement in insulin sensitivity (homeostatic model assessment of insulin resistance; HOMA) (47) and the incidence of type 2 diabetes by 52 % over 4 years (30) . Benefits shown in studies with nuts included as part of the intervention diet (NORDIET (46) or Mediterranean diet (47) ) may have been partly due to other components of these diets (62) .…”

“…Other bioactive nutrients in nuts may benefit glucoregulation (27) , endothelial function, blood pressure control (28) and inflammation (21) . Studies have demonstrated that higher nut consumers are at a significantly lower risk of non-cardiovascular inflammatory disease mortality (29) and risk of developing type 2 diabetes (30) than low nut consumers. These benefits may be attributed to their nutrient profile; plant-derived n-3 fatty acids (a-linolenic acid; ALA) found in walnuts have been shown in clinical and epidemiological studies to improve inflammation, arterial compliance, insulin resistance, endothelial function and blood pressure (31 -34) .…”

Olive oil has a beneficial effect on impaired glucose regulation and other cardiometabolic risk factors. Di@bet.es study

“…11 The results of this national, crosssectional study show that obese persons and persons with a carbohydrate metabolism disorder generally consumed less olive oil and that persons who consumed olive oil tended to have a lower prevalence of obesity and type 2 diabetes mellitus, supporting the hypothesis of a lower risk for obesity and type 2 diabetes mellitus in persons who consume olive oil, as found in several prospective studies 32,33 and in a recent clinical trial in persons at high risk for cardiovascular disease. 34 Of particular note was the association found between olive oil consumption and the population pattern of insulin resistance. Insulin resistance is generally agreed to increase with the consumption of saturated fatty acids 35 and decrease with the consumption of n-3 fatty acids, 36 with the effect of n-6 fatty acids being controversial.…”

Mediterranean Diet attenuates risk of frailty and sarcopenia: New insights and future directions

“…The Mediterranean Diet (MedDiet) is an example of a dietary pattern that provides evidence for an association between diet quality and healthy ageing [50][51][52][53]. There is evidence suggesting that greater adherence to a MedDiet is associated with substantial reductions in the risk of several major age-related diseases including cardiovascular disease (CVD) [54], overall cancer risk [55], type 2 diabetes mellitus (T2DM) [56][57][58] and cognitive decline [59,60].…”