Acute and second-meal effects of almond form in impaired glucose tolerant adults: a randomized crossover trial.
ABSTRACT: BACKGROUND: Nut consumption may reduce the risk of developing type 2 diabetes. The aim of the current study was to measure the acute and second-meal effects of morning almond consumption and determine the contribution of different nut fractions. METHODS: Fourteen impaired glucose tolerant (IGT) adults participated in a randomized; 5-arm; crossover design study where whole almonds (WA); almond butter (AB); defatted almond flour (AF); almond oil (AO) or no almonds (vehicle - V) were incorporated into a 75g available carbohydrate-matched breakfast meal. Postprandial concentrations of blood glucose; insulin; non-esterified free fatty acids (NEFA); glucagon-like peptide-1 (GLP-1) and appetitive sensations were assessed after treatment breakfasts and a standard lunch. RESULTS: WA significantly attenuated second-meal and daylong blood glucose incremental area under the curve (AUCI) and provided the greatest daylong feeling of fullness. AB and AO decreased blood glucose AUCI in the morning period and daylong blood glucose AUCI was attenuated with AO. WA and AO elicited a greater second-meal insulin response; particularly in the early postprandial phase; and concurrently suppressed the second-meal NEFA response. GLP-1 concentrations did not vary significantly between treatments. CONCLUSIONS: Inclusion of almonds in the breakfast meal decreased blood glucose concentrations and increased satiety both acutely and after a second-meal in adults with IGT. The lipid component of almonds is likely responsible for the immediate post-ingestive response; although it cannot explain the differential second-meal response to AB versus WA and AO.
Nuts and health outcomes: new epidemiologic evidence.
This article reviews recent epidemiologic evidence on nut intake and health outcomes. It focuses on studies in which nut consumption is directly assessed or when nuts are included in a dietary score or pattern. Epidemiologic studies have been remarkably consistent in showing an association between nut consumption and a reduced risk of coronary heart disease (CHD). Some evidence has emerged recently to suggest health-protective benefits of nuts other than CHD. Frequent nut intake probably reduces risk of diabetes mellitus among women; but its effects on men are unknown. Evidence on the anticarcinogenic effects of nuts is somewhat limited because studies in the past 2 decades have examined only 3 tumor sites; and the benefits appear to be manifested only in women. However; the protective benefits of frequent nut consumption on gallstone diseases are observed in both sexes. Long-term nut consumption is linked with lower body weight and lower risk of obesity and weight gain. A dietary pattern or score that includes nuts is consistently related with beneficial health outcomes; and this provides an indirect evidence of the salutary benefits of nut consumption. More longitudinal studies are needed to clarify the possible effects of nuts on diseases other than CHD.
Reduction in the Incidence of Type 2-Diabetes with the Mediterranean Diet: Results of the PREDIMED-Reus Nutrition Intervention Randomized Trial
Objective: To test the effects of two Mediterranean-diet interventions versus a low-fat diet on incidence of diabetes. Research Design and Methods: Three-arm randomized trial in 418 nondiabetic subjects aged 55-80 years recruited in one center (PREDIMED-Reus; North-Eastern Spain) of the PREDIMED study; a large nutrition-intervention trial for primary cardiovascular prevention in persons at high cardiovascular risk. Participants were randomized to education on a low-fat diet (control group) or one of two Mediterranean diets; 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. Results: After a median follow-up of 4.0 years; diabetes incidence was 10.1% (95% confidence interval [CI]; 5.1-15.1); 11.0% (5.9-16.1); and 17.9% (11.4-24.4) in the Mediterranean-diet with olive oil group; the Mediterranean-diet 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 Mediterranean-diet groups supplemented with olive oil and nuts; respectively; compared to the control group. When pooling the two Mediterranean-diet groups compared to the control group; diabetes incidence was reduced by 52% (27-86). In all study arms; increased adherence to the Mediterranean-diet was inversely associated with diabetes incidence. Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity. Conclusion - Mediterranean diets without calorie restriction appear to be effective in the prevention of diabetes in subjects at high cardiovascular risk.
Scientific evidence of interventions using the Mediterranean diet: A systematic review.
The Mediterranean Diet has been associated with greater longevity and quality of life in epidemiological studies; the majority being observational. The application of evidence-based medicine to the area of public health nutrition involves the necessity of developing clinical trials and systematic reviews to develop sound recommendations. The purpose of this study was to analyze and review the experimental studies on Mediterranean diet and disease prevention. A systematic review was made and a total of 43 articles corresponding to 35 different experimental studies were selected. Results were analyzed for the effects of the Mediterranean diet on lipoproteins; endothelial resistance; diabetes and antioxidative capacity; cardiovascular diseases; arthritis; cancer; body composition; and psychological function. The Mediterranean diet showed favorable effects on lipoprotein levels; endothelium vasodilatation; insulin resistance; metabolic syndrome; antioxidant capacity; myocardial and cardiovascular mortality; and cancer incidence in obese patients and in those with previous myocardial infarction. Results disclose the mechanisms of the Mediterranean diet in disease prevention; particularly in cardiovascular disease secondary prevention; but also emphasize the need to undertake experimental research and systematic reviews in the areas of primary prevention of cardiovascular disease; hypertension; diabetes; obesity; infectious diseases; age-related cognitive impairment; and cancer; among others. Interventions should use food scores or patterns to ascertain adherence to the Mediterranean diet. Further experimental research is needed to corroborate the benefits of the Mediterranean diet and the underlying mechanisms; and in this sense the methodology of the ongoing PREDIMED study is explained.
The effects of high walnut and cashew nut diets on the antioxidant status of subjects with metabolic syndrome.
Background Nut consumption is associated with a protective effect against coronary
heart disease; partly due to its high antioxidant content. It is hypothesized that the inclusion of nuts in the diet will improve the antioxidant status of subjects with metabolic syndrome who may be vulnerable to impaired antioxidant status. Aim The effects of high cashew nut and high walnut diets on the antioxidant status of subjects with metabolic syndrome are investigated. Methodology Sixty-four volunteers (29 male and35 female; 45 ± 10y) with metabolic syndrome (diagnosed by using the ATP III criteria) received a prudent control diet; prepared in the metabolic kitchen of the North-West University; Potchefstroom campus (NWU-PC) for a period of 3 weeks (run-in). The participants were grouped according to gender and age and randomized into three groups; receiving either the walnut; cashew nut or the control diets for 8 weeks; while maintaining a stable body weight. Nuts provided 20% of daily energy intake. Fasting blood samples were taken after the run-in period (baseline) and at the end of the intervention period and analyzed for various antioxidant capacity markers. Results The oxygen radical absorbance capacity (ORAC) of the walnut and cashew nut diets were significantly higher than the control diet. Despite this; the walnut and cashew nut diets had no significant effects on serum ORAC; reduced (GSH); oxidized (GSSG) glutathione; GSH:GSSG or diacron reactive metabolites (dRom) (total oxidant status) levels compared to the control group. However; all three groups showed significant improvements in antioxidant status from baseline to end (GSSG and dRom levels decreased; GSG:GSSG ratio and ORAC levels increased). This may be due to a general increased antioxidant intake from the prudent diet compared to the habitual diets. Conclusion Although the inclusion of walnuts and cashew nuts into a prudent diet resulted in an increased antioxidant capacity (ORAC) of the nut diets; compared to the control diet; it did not improve the serum antioxidant profiles of subjects with metabolic syndrome.
Regular Consumption of Nuts Is Associated with a Lower Risk of Cardiovascular Disease in Women with Type 2 Diabetes.
Higher nut consumption has been associated with lower risk of coronary heart disease (CHD) events in several epidemiologic studies. The study examined the association between intake of nuts and incident cardiovascular disease (CVD) in a cohort of women with type 2 diabetes. For the primary analysis; there were 6309 women with type 2 diabetes who completed a validated FFQ every 2Â4 y between 1980 and 2002 and were without CVD or cancer at study entry. Major CVD events included incident myocardial infarction (MI); revascularization; and stroke. During 54;656 person-years of follow-up; there were 452 CHD events (including MI and revascularization) and 182 incident stroke cases. Frequent nut and peanut butter consumption was inversely associated with total CVD risk in age-adjusted analyses. After adjustment for conventional CVD risk factors; consumption of at least 5 servings/wk of nuts or peanut butter [serving size; 28 g (1 ounce) for nuts and 16 g (1 tablespoon) for peanut butter] was significantly associated with a lower risk of CVD (relative risk = 0.56; 95% CI: 0.36Â0.89). Furthermore; when we evaluated plasma lipid and inflammatory biomarkers; we observed that increasing nut consumption was significantly associated with a more favorable plasma lipid profile; including lower LDL cholesterol; non-HDL cholesterol; total cholesterol; and apolipoprotein-B-100 concentrations. However; we did not observe significant associations for HDL cholesterol or inflammatory markers. These data suggest that frequent nut and peanut butter consumption is associated with a significantly lower CVD risk in women with type 2 diabetes.
Adherence to the Mediterranean dietary pattern is positively associated with plasma adiponectin concentrations in diabetic women.
Background: Although the typical diet of the Mediterranean region has received much recognition over the past several years for its association with substantial health benefits; it remains unknown whether its favorable effects are mediated through changes in adiponectin concentrations. Objective: The objective was to determine whether adherence to a Mediterranean-type diet is associated with higher plasma adiponectin concentrations. Design: This study was a prospective and cross-sectional evaluation of plasma adiponectin concentrations and dietary data from 987 diabetic women from the Nurses Health Study who had no history of cardiovascular disease at the time blood was drawn in 1990. Results: Women who scored highest on a 9-point scale that measures adherence to a Mediterranean-type dietary pattern tended to be older; were less likely to be current smokers; had lower body mass indexes and waist circumferences; and had higher total energy intakes; physical activities; and plasma adiponectin concentrations than did women with the lowest scores. Median plasma adiponectin concentrations were 23% higher in women who most closely followed a Mediterranean-type diet than in low adherers after adjustment for age and energy intake (P < 0.01). Body composition; lifestyle; and medical history explained some; but not all; of the observed association between diet and adiponectin concentrations because high adherers tended to have greater adiponectin concentrations than did moderate or low adherers; even after adjustment for these variables. Conclusions: Our data suggest that; of the several components of the Mediterranean dietary pattern score; alcohol; nuts; and whole grains show the strongest association with adiponectin concentrations. Close adherence to a Mediterranean-type diet is associated with higher adiponectin concentrations.
Dietary patterns and risk for type 2 diabetes mellitus in U.S. men.
Background: The role of diet in the development of type 2 diabetes mellitus remains unsettled.
Objective: To examine the association between major dietary patterns and risk for type 2 diabetes mellitus. Design: Prospective cohort study. Setting: United States. Participants: 42 504 male health professionals; 40 to 75 years of age; without diagnosed diabetes; cardiovascular disease; or cancer at baseline. Measurements: Using factor analysis based on data from food frequency questionnaires; we identified and validated two major dietary patterns that we labeled Âprudent (characterized by higher consumption of vegetables; fruit; fish; poultry and whole grains) and Âwestern (characterized by higher consumption of red meat; processed meat; French fries; high-fat dairy products; refined grains; and sweets and desserts). Relative risks and 95% CIs were adjusted for potential confounders; including body mass index (BMI); physical activity; and cigarette smoking. Results: During 12 years of follow-up (466 508 person-years); we documented 1321 cases of type 2 diabetes. The prudent dietary pattern score was associated with a modestly lower risk for type 2 diabetes (relative risk for extreme quintiles; 0.84 [CI; 0.70 to 1.00]). In contrast; the western dietary pattern score was associated with an increased risk for type 2 diabetes (relative risk; 1.59 [CI; 1.32 to 1.93]; P < 0.001 for trend). A high score for the western dietary pattern combined with low physical activity (relative risk comparing extreme quintiles of dietary pattern score and physical activity; 1.96 [CI; 1.35 to 2.84]) or obesity (relative risk for BMI =30 kg/m2 vs. <25 kg/m2; 11.2 [CI; 8.07 to 15.6]) was associated with a particularly high risk for type 2 diabetes. Conclusion: Our findings suggest that a western dietary pattern is associated with a substantially increased risk for type 2 diabetes in men.
Almond consumption and cardiovascular risk factors in adults with prediabetes
OBJECTIVE: The authors tested the hypothesis that in adults with prediabetes; an almond-enriched American Diabetes Association (ADA) diet improves measures of insulin sensitivity and other cardiovascular risk factors compared with an ADA nut-free diet. METHODS: DESIGN: Randomized parallel-group trial. SETTING: Outpatient dietary counseling and blood analysis. SUBJECTS: Sixty-five adult participants with prediabetes. INTERVENTION: Sixteen weeks of dietary modification featuring an ADA diet containing 20% of energy from almonds (approximately 2 oz per day). Measures of Outcome: Outcomes included fasting glucose; insulin; total cholesterol (TC); low-density lipoprotein cholesterol (LDL-C); high-density lipoprotein cholesterol (HDL-C); triglycerides; TC:HDL-C; and HbA1c; which were measured at weeks 0; 8; and 16. Body weight; body mass index (BMI); waist circumference; blood pressure; and nutrient intake were measured at weeks 0; 4; 8; 12; and 16. RESULTS: The almond-enriched intervention group exhibited greater reductions in insulin (-1.78 µU/ml vs. +1.47 µU/ml; p = 0.002); homeostasis model analysis for insulin resistance (-0.48 vs. +0.30; p = 0.007); and homeostasis model analysis for beta-cell function (-13.2 vs. +22.3; p = 0.001) compared with the nut-free control group. Clinically significant declines in LDL-C were found in the almond-enriched intervention group (-12.4 mg/dl vs. -0.4 mg/dl) as compared with the nut-free control group. No changes were observed in BMI (-0.4 vs. -0.7 kg/m(2); p = 0.191); systolic blood pressure (-4.4 mm Hg vs. -3.5 mm Hg; p = 0.773); or for the other measured cardiovascular risk factors. CONCLUSIONS: An ADA diet consisting of 20% of calories as almonds over a 16-week period is effective in improving markers of insulin sensitivity and yields clinically significant improvements in LDL-C in adults with prediabetes.
Hydro-ethanolic extract of cashew tree (Anacardium occidentale) nut and its principal compound; anacardic acid; stimulate glucose uptake in C2C12 muscle cells
Scope: Products of cashew tree (Anacardium occidentale) are used in traditional medicine for various ailments; including diabetes.Methods and results: The anti-diabetic properties of cashew plant parts were studied using differentiated C2C12 myoblasts (myotubes) and rat liver mitochondria. Hydroethanolic extract of cashew seed (CSE) and its active component; anacardic acid (AA); stimulated glucose transport into C2C12 myotubes in a concentration-dependent manner. Extracts of other parts (leaves; bark and apple) of cashew plant were inactive. Significant synergistic effect on glucose uptake with insulin was noticed at 100 mug/mL CSE. CSE and AA caused activation of adenosine monophosphate-activated protein kinase in C2C12 myotubes after 6 h of incubation. No significant effect was noticed on Akt and insulin receptor phosphorylation. Both CSE and AA exerted significant uncoupling of succinate-stimulated respiration in rat liver mitochondria.Conclusion: Activation of adenosine monophosphate-activated protein kinase by CSE and AA likely increases plasma membrane glucose transporters; resulting in elevated glucose uptake. In addition; the dysfunction of mitochondrial oxidative phosphorylation may enhance glycolysis and contribute to increased glucose uptake. These results collectively suggest that CSE may be a potential anti-diabetic nutraceutical.