Garg M.L., R.J. Blake, R.B. Wills, E.H. Clayton, 2007. Macadamia nut consumption modulates favourably risk factors for coronary artery disease in hypercholesterolemic subjects. Lipids. 42(6):583-7.
Macadamia nuts are rich source of monounsaturated fats (oleic and palmitoleic acids) and contain polyphenol compounds, therefore, their consumption can be expected to impart health benefits to humans. This study was conducted to examine the effects of consuming macadamia nuts in hypercholesterolemic male individuals on plasma biomarkers of oxidative stress, coagulation and inflammation. Seventeen hypercholesterolemic male subjects were given macadamia nuts (40-90 g/day), equivalent to 15% energy intake, for a period of 4 weeks. As expected, monounsaturated fatty acids (16:1n-7, 18:1n-9 and 20:1n-9) were elevated in the plasma lipids of all volunteers following intervention with macadamia nuts. Plasma markers of inflammation (leukotriene, LTB(4)) and oxidative stress (8-isoprostane) were significantly lower (1,353 ± 225 vs. 1,030 ± 129 pg/mL and 876 ± 97 vs. 679 ± 116 pg/mL, respectively) within 4 weeks following macadamia nut intervention. There was a non-significant (23.6%) reduction in the plasma TXB(2)/PGI(2) ratio following macadamia nut consumption. This study demonstrates, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake. These data, combined with our previous results on cholesterol-lowering effects of macadamia nuts, suggest that regular consumption of macadamia nuts may play a role in the prevention of coronary artery disease.
Mercanligil S.M., P. Arslan, C. Alasalvar, E. Okut, E. Akgül, A. Pinar, P.O. Geyik, L. Tokgözoğlu, F. Shahidi, – 2007. Effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men. European Journal of Clinical Nutrition. 61, 212-220.
Objective: Frequent consumption of nuts is associated with favorable plasma lipid profiles and reduced risk of coronary heart disease (CHD). This study was conducted to investigate the effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men compared with baseline and control diet, and also to measure the anthropometric parameters, habitual physical activities, nutrient intake and endothelial function. Subjects and design: Fifteen hypercholesterolemic men aged 4878 years were recruited voluntarily. A well-controlled, 2-period (P1and P2) study design with a total of 8-week was implemented. In the P1, subjects consumed a control diet (low-fat, low-cholesterol and high-carbohydrate). During the P2, the control diet was supplemented with MUFA-rich hazelnut (40 g/day), which provided 11.6% of total energy content. Anthropometric parameters and habitual physical activities were recorded. Plasma total and HDL cholesterol, TAG, ApoA-1, Apo B, total homocysteine and glucose concentrations were measured. All parameters and measurements were obtained at baseline and end of each 4-week diet period. Results: Body weights of subjects remained stable throughout the study. Compared with baseline, the hazelnut-enriched diet decreased (P<0.05) the concentrations of VLDL cholesterol, triacylglycerol, apolipoprotein B by 29.5, 31.8, and 9.2%, respectively, while increasing HDL cholesterol concentrations by 12.6%. Total/HDL cholesterol and LDL/HDL cholesterol ratios favorably decreased (P<0.05). Although insignificant there was a decreasing trend for the rest of parameters, particularly in total (5.2%) and LDL cholesterol (3.3%) in subjects consuming a hazelnut-enriched diet compared to that of the baseline. No changes were found in fasting levels of glucose, Apo A-1 and homocysteine between the control and hazelnut-enriched diets. Conclusions: This study demonstrated that a high-fat and high-MUFA-rich hazelnut diet was superior to a low-fat control diet because of favorable changes in plasma lipid profiles of hypercholesterolemic adult men and, thereby positively affecting the CHD risk profile.
Josse, A.R., C.W.C. Kendall, L.S.A. Augustin, P.R. Ellis, D.J.A. Jenkins, 2007. Almonds and postprandial glycemia – a dose-response study. Metabolism. 56(3):400-404.
Almonds, together with other nuts, reduce serum cholesterol levels and may reduce the risk of coronary heart disease. There is much current interest in the relation of coronary heart disease to postprandial events. We have therefore assessed the effects of varying amounts of almonds on the postprandial blood glucose response to a carbohydrate meal. Our aim was to assess the effect of adding almonds to a bread meal. Nine healthy volunteers (2 women, 7 men; mean age, 27.8 years; mean body mass index, 22.9 kg/m2) were randomly fed with 3 test meals and 2 white bread control meals on separate days. Subjects were fed the meals after a 10- to 12-hour overnight fast. Each meal contained 50 g of available carbohydrate from white bread eaten alone or with 30, 60, or 90 g (~1, 2, or 3 oz) of almonds. Capillary fingerprick blood samples for glucose analysis were obtained at 0, 15, 30, 45, 60, 90, and 120 minutes. Glycemic responses were assessed by calculating the incremental area under the 2-hour blood glucose curve. The addition of almonds to white bread resulted in a progressive reduction in the glycemic index of the composite meal in a dose-dependent manner for the 30-g (105.8 ± 23.3), 60-g (63.0 ± 9.0), and 90-g (45.2 ± 5.8) doses of almonds (r = 0.524, n = 36, P = .001). We conclude that, in addition to lowering serum cholesterol levels, almonds may also reduce the glycemic impact of carbohydrate foods with which they are eaten.
Joice, C., 2007. A practical approach to the Portfolio Eating Plan; a dietary regime to prevent cardiovascular disease. Cah Nutr Diét. 42(1):42-45.
(As translated from French) Current dietary strategies for the treatment of coronary heart disease have expanded beyond the restriction of saturated and trans-fat and cholesterol to include viscous fibers, plant sterols, vegetable protein foods (soy) and nuts (almonds). Research at the University of Toronto, Canada, has shown that combining these dietary components in a single dietary strategy, known as the Portfolio eating plan, results in cholesterol reduction proven to be equivalent to a starting therapeutic dose of first generation statins. This overview of the clinical research studies demonstrates the effectiveness of the Portfolio eating plan and focuses on the necessary dietary modifications to realize the goals of this cardio-protective dietary strategy. In addition, a perspective is directed towards the Mediterranean diet, a regime well recognized in France for its cardiovascular benefits.
Jenkins, D.J.A., C.W.C. Kendall, T.H. Nguyen, J. Teitel, A. Marchie, M. Chius, A.Y. Taha, D.A. Faulkner, T. Kemp, J.M.W. Wong, R. de Souza, A. Emam, E.A. Trautwein, K.G. Lapsley, C. Holmes, R.G. Josse, L. A. Leiter, W. Singer, 2007. Effect on hematologic risk factors for coronary heart disease of a cholesterol reducing diet. Eur. J. Clin. Nutr. 61:483-492.
A dietary portfolio of cholesterol-lowering ingredients has proved effective in reducing serum cholesterol. However, it is not known whether this dietary combination will also affect hematologic risk factors for coronary heart disease (CHD). Reductions in hematocrit and polymorphonuclear leukocytes have been reported to improve cardiovascular risk. We, therefore, report changes in hematological indices, which have been linked to cardiovascular health, in a 1-year assessment of subjects taking an effective dietary combination (portfolio) of cholesterol-lowering foods.
Fitó, M., M. Guxens, D. Corella, G. Sáez, R. Estruch, R. de la Torre, F. Francés, C. Cabezas, M. del C. López-Sabaterl, J. Marrugat, A. García-Arellano, F. Arós, V. Ruiz-Gutierrez, E. Ros, J. Salas-Salvadó, M. Fiol, R. Solá, M.I. Covas; for the PREDIMED Study, 2007. Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial. Arch Intern Med. 167:1195-203.
Background: Despite the richness in antioxidants of the Mediterranean diet, to our knowledge, no randomized controlled trials have assessed its effect on in vivo lipoprotein oxidation. Methods: A total of 372 subjects at high cardiovascular risk (210 women and 162 men; age range, 55-80 years), who were recruited into a large, multicenter, randomized, controlled, parallel-group clinical trial (the Prevencio’n con Dieta Mediterra’nea [PREDIMED] Study) directed at testing the efficacy of the traditional Mediterranean diet (TMD) on the primary prevention of coronary heart disease, were assigned to a low-fat diet (n=121) or one of 2 TMDs (TMD + virgin olive oil or TMD + nuts). The TMD participants received nutritional education and either free virgin olive oil for all the family (1 L/wk) or free nuts (30 g/d). Diets were ad libitum. Changes in oxidative stress markers were evaluated at 3 months. Results: After the 3-month interventions, mean (95% confidence intervals) oxidized low-density lipoprotein (LDL) levels decreased in the TMD + virgin olive oil (−10.6 U/L [−14.2 to −6.1]) and TMD + nuts (−7.3 U/L [−11.2 to −3.3]) groups, without changes in the low-fat diet group (−2.9 U/L [−7.3 to 1.5]). Change in oxidized LDL levels in the TMD + virgin olive oil group reached significance vs that of the low-fat group (P=.02). Malondialdehyde changes in mononuclear cells paralleled those of oxidized LDL. No changes in serum glutathione peroxidase activity were observed. Conclusions: Individuals at high cardiovascular risk who improved their diet toward a TMD pattern showed significant reductions in cellular lipid levels and LDL oxidation. Results provide further evidence to recommend the TMD as a useful tool against risk factors for CHD.
Davis, P., G. Valacchi, E. Pagnin, Q. Shao, H.B. Gross, L. Calo, W. Yokoyama, 2006. Walnuts reduce aortic ET-1 mRNA levels in hamsters fed a high-fat, atherogenic diet. J. Nutr. 136(2):428-32
Walnut consumption is associated with reduced coronary vascular disease (CVD) risk; however, the mechanisms responsible remain incompletely understood. Recent clinical studies suggested that these mechanisms involve nonplasma lipid related effects on endothelial function. Male Golden Syrian hamsters (12 groups, n ý 10ý15) were fed for 26 wk atherosclerotic, high-fat, hyperlipidemic diets with increasing concentrations of whole walnuts (61ý150 g/kg diet), or a-tocopherol (a-T, 8.1ý81 mg/kg diet) and single diets with either walnut oil (32 g/kg diet) or pure g-tocopherol (g-T; 81 mg/kg diet) added. Aortic endothelin 1 (ET-1), an important endothelial regulator, was assayed as mRNA. Aortic cholesterol ester (CE) concentration along with other vascular stress markers (Cu/Zn and Mn superoxide dismutase, biliverdin reductase) and plasma lipid concentrations were determined. Hyperlipidemia (plasma LDL cholesterol ;6 times normal) occurred in all groups. Aortic CE concentration, a measure of atherosclerotic plaque, was highest in the lowest a-T only group and declined significantly with increasing a-T. The aortic CE of all walnut groups was decreased significantly relative to the lowest a-T only group but showed no dose response. The diets did not produce changes in the other vascular stress markers, whereas aortic ET-1 mRNA levels declined dramatically with increasing dietary walnuts (to a 75% reduction in the highest walnut content group compared with the lowest a-T group) but were unaltered in the a-T groups or g-T group. The study results are consistent with those of human walnut feeding studies and suggest that the mechanisms underlying those results are mediated in part by ET-1ýdependent mechanisms. The contrasting results between the a-tocopherol or g-tocopherol diets and the walnut diets also make it unlikely that the nonplasma lipid related CVD effects of walnuts are due to their a-tocopherol or g-tocopherol content. Finally, the results indicate that the walnut fat compartment is a likely location for the components responsible for the reduced aortic CE concentration. This study was designed to determine the mechanisms behind walnuts’ ability to reduce coronary vascular disease risk. Male Golden Syrian hamsters fed high-fat, hyperlipidemic diets supplemented with either walnuts; alpha-tocopherol, a form of vitamin E; walnut oil; or gamma-tocopherol, the form of vitamin E found in walnuts. Hamsters fed the walnut supplemented diet had the greatest reduction in aortic endothelin, an endothelial cell regulator, and the lowest concentration of aortic cholesterol ester, a measure of arterial plaque development.
Cortés, B., I. Núñez, M. Cofán, R. Gilabert, A. Pérez-Heras, E. Casals, R. Deulofeu, E. Ros, 2006. Acute effects of high-fat meals enriched with walnuts or olive oil on postprandial endothelial function. J Am Coll Cardiol. 48:1666 -71.
Objectives: We sought to investigate whether the addition of walnuts or olive oil to a fatty meal have differential effects on postprandial vasoactivity, lipoproteins, markers of oxidation and endothelial activation, and plasma asymmetric dimethylarginine (ADMA). Background: Compared with a Mediterranean diet, a walnut diet has been shown to improve endothelial function in hypercholesterolemic patients. We hypothesized that walnuts would reverse postprandial endothelial dysfunction associated with consumption of a fatty meal. Methods: We randomized in a crossover design 12 healthy subjects and 12 patients with hypercholesterolemia to 2 high-fat meal sequences to which 25 g olive oil or 40 g walnuts had been added. Both test meals contained 80 g fat and 35% saturated fatty acids, and consumption of each meal was separated by 1 week. Venipunctures and ultrasound measurements of brachial artery endothelial function were performed after fasting and 4 h after test meals. Results: In both study groups, flow-mediated dilation (FMD) was worse after the olive oil meal than after the walnut meal (p = 0.006, time-period interaction). Fasting, but not postprandial, triglyceride concentrations correlated inversely with FMD (r = -0.324; p = 0.024). Flow independent dilation and plasma ADMA concentrations were unchanged, and the concentration of oxidized low-density lipoproteins decreased (p = 0.051) after either meal. The plasma concentrations of soluble inflammatory cytokines and adhesion molecules decreased (p < 0.01) independently of meal type, except for E-selectin, which decreased more (p = 0.033) after the walnut meal. Conclusions: Adding walnuts to a high-fat meal acutely improves FMD independently of changes in oxidation, inflammation, or ADMA. Both walnuts and olive oil preserve the protective phenotype of endothelial cell
Jenkins J. D. A., C. W. C. Kendall, A. R. Josse, S. Salvatore, F. Brighenti, L. S. A. Augustin, P. R. Ellis, E. Vidgen, and A. V. Rao. 2006. Almonds decrease postprandial glycemia, insulinemia, and oxidative damage in healthy individuals. J Nutr. 136:1-6.
Strategies that decrease postprandial glucose excursions, including digestive enzyme inhibition, and low glycemic index diets result in lower diabetes incidence and coronary heart disease (CHD) risk, possibly through lower postprandial oxidative damage to lipids and proteins. We therefore assessed the effect of decreasing postprandial glucose excursions on measures of oxidative damage. Fifteen healthy subjects ate 2 bread control meals and 3 test meals: almonds and bread; parboiled rice; and instant mashed potatoes, balanced in carbohydrate, fat, and protein, using butter and cheese. We obtained blood samples at baseline and for 4 h postprandially. Glycemic indices for the rice (38 ± 6) and almond meals (55 ± 7) were less than for the potato meal (94 ± 11) (P < 0.003), as were the postprandial areas under the insulin concentration time curve (P < 0.001). No postmeal treatment differences were seen in total antioxidant capacity. However, the serum protein thiol concentration increased following the almond meal (15±14 mmol/L), indicating less oxidative protein damage, and decreased after the control bread, rice, and potato meals (-10 ± 8 mmol/L), when data from these 3 meals were pooled (P = 0.021). The change in protein thiols was also negatively related to the postprandial incremental peak glucose (r = -0.29, n = 60 observations, P = 0.026) and peak insulin responses (r = -0.26, n = 60 observations, P = 0.046). Therefore, lowering postprandial glucose excursions may decrease the risk of oxidative damage to proteins. Almonds are likely to lower this risk by decreasing the glycemic excursion and by providing antioxidants. These actions may relate to mechanisms by which nuts are associated with a decreased risk of CHD.
Jenkins, D.J.A, C.W.C. Kendall, D.A. Faulkner, T. Nguyen, T. Kemp, A. Marchie, J. M. W. Wong, R. de Souza, A. Emam, E. Vidgen, E. A. Trautwein, K. G. Lapsley, C. Holmes, R. G. Josse, L. A. Leiter, P. W. Connelly, and W. Singer, 2006. Assessment of the longer-term effects of a portfolio of cholesterol-lowering foods in hypercholesterolemia. Am J Clin Nutr. 83:582-91.
Background: Cholesterol-lowering foods may be more effective when consumed as combinations rather than as single foods. Objectives: Our aims were to determine the effectiveness of consuming a combination of cholesterol-lowering foods (dietary portfolio) under real-world conditions and to compare these results with published data from the same participants who had undergone 4-wk metabolic studies to compare the same dietary portfolio with the effects of a statin. Design: For 12 mo, 66 hyperlipidemic participants were prescribed diets high in plant sterols (1.0 g/1000 kcal), soy protein (22.5 g/1000 kcal), viscous fibers (10 g/1000 kcal), and almonds (23 g/1000 kcal). Fifty-five participants completed the 1-y study. The 1-y data were also compared with published results on 29 of the participants who had also undergone separate 1-mo metabolic trials of a diet and a statin. Results: At 3 mo and 1 y, mean (±SE) LDL-cholesterol reductions appeared stable at 14.0 ± 1.6% (P < 0.001) and 12.8 ± 2.0% (P <0.001), respectively (n = 66). These reductions were less than those observed after the 1-mo metabolic diet and statin trials. Nevertheless, 31.8% of the participants (n = 21 of 66) had LDL-cholesterol reductions of >20% at 1 y (x ± SE: -29.7 ± 1.6%). The LDL cholesterol reductions in this group were not significantly different from those seen after their respective metabolically controlled portfolio or statin treatments. A correlation was found between total dietary adherence and LDL-cholesterol change (r =-0.42, P<0.001). Only 2 of the 26 participants with <55% compliance achieved LDL-cholesterol reductions >20% at 1 y. Conclusions: More than 30% of motivated participants who ate the dietary portfolio of cholesterol-lowering foods under real-world conditions were able to lower LDL-cholesterol concentrations >20%, which was not significantly different from their response to a first-generation statin taken under metabolically controlled conditions.
