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.
Ternus, M., K. Lapsley, K. McMahon, G. Johnson, 2006. Qualified health claim for nuts and heart disease prevention, development of consumer-friendly language. Nutrition Today. 41(2):62-66.
In 2003, the US Food and Drug Administration (FDA) began authorizing qualified health claims for conventional foods. Although the FDA had developed generic qualifying language for these claims, the language had not yet been tested with consumers. A shopping mall intercept was conducted among a random sample of 408 adults. The research tested consumer preference, understanding and believability, and impact on nut consumption of 4 variations of the ‘‘B’’ level qualified health claim for nuts and heart disease. The FDA generic language was used as the control. The results show that one of the alternatives was ranked significantly higher than the FDA generic claim for clarity and understandability but was similar in all other categories, including the scientific uncertainty associated with the claim. This research demonstrates that it is possible to meet FDA’s standards for truthful and not misleading health claims using consumer-friendly language.
Serra-Majem, L., B. Roman, R. Estruch, 2006. Scientific evidence of interventions using the Mediterranean diet: A systematic review. Nutrition Reviews. 64(2):S27-S47.
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.
Salas-Salvado’, J., M. Bullo’, A. Pe’rez-Heras, E. Ros, 2006. Dietary fiber, nuts and cardiovascular diseases. British Journal of Nutrition. 96, Suppl. 2, S45-S51.
Dietary fiber has a range of metabolic health benefits. Through a variety of mechanisms, dietary fiber, and the viscous variety in particular, slows down gastric emptying and intestinal transit, decreases the rate of intestinal carbohydrate absorption, and increases fecal bile acid excretion. Therefore, consumption of some types of soluble fiber can enhance satiety, which is associated with a lower BMI, and reduce blood cholesterol and the postprandial glucose response. Surprisingly, the consumption of insoluble fiber from whole grains, though metabolically inert, has been associated with a reduction in the risk of developing coronary heart disease and diabetes in epidemiological studies. The likely reason is that whole grains, like nuts, legumes and other edible seeds, contain many bioactive phytochemicals and various antioxidants. After cereals, nuts are the vegetable foods that are richest in fiber, which may partly explain their benefit on the lipid profile and cardiovascular health.
Kocyigit, A., A.A. Koylu, H. Keles, 2006. Effects of pistachio nuts consumption on plasma lipid profile and oxidative status in healthy volunteers. Nutrition, Metabolism & Cardiovascular Diseases. 16:202-9.
Background and aim: Effects of pistachio nuts consumption on plasma lipid profile and oxidative status were investigated in healthy volunteers with normal lipid levels. Methods and results: The study was conducted in 24 healthy men and 20 healthy women. All subjects consumed their regular diets during a 1-week period. After this period, half of the subjects (12 men and 10 women, mean age 32.8 ± 6.7 years) were randomized to a regular diet group and the other half (12 men and 10 women, mean age 33.4 ± 7.2 years) were randomized to a pistachio group which involved substituting pistachio nuts for 20% of their daily caloric intake for 3 weeks. Plasma total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride, malondialdehyde (MDA) and antioxidant potential (AOP) were measured before and after the dietary modification from all the subjects. After 3 weeks, with the pistachio diet, the mean plasma total cholesterol, MDA levels and, total cholesterol/ HDL and LDL/HDL ratios were found to be significantly decreased (P 0.05). Conclusion: These results indicated that consumption of pistachio nuts decreased oxidative stress, and improved total cholesterol and HDL levels in healthy volunteers.
Brufau, G., J. Boatella, M. Rafecas, 2006. Nuts: source of energy and macronutrients. British Journal of Nutrition. 96, Suppl. 2, S24-S28.
On the basis of the high fat content of nuts, they are traditionally considered as foods that provide a high amount of energy. However, epidemiologic and clinical observations do not indicate an association between nut intake and increased BMI. There is a notorious variability in macronutrient composition among nuts, although they have some consistent patterns. Nuts contain all major macronutrients: protein, carbohydrate, and fat. The total protein content is relatively high, which makes them a good source of plant protein (especially for vegetarians). Although nuts contain low amounts of some essential amino acids, this is not a nutritional concern due to the complement of protein. In addition, nuts have a low lysine:arginine ratio, which is inversely associated with the risk of developing hypercholesterolemia and atherosclerosis. Carbohydrates are the second highest macronutrient in nuts in terms of total calories provided. The fat fraction is characterized by a high amount of unsaturated fatty acids and a low content of saturated fatty acids. In conclusion, the high content in unsaturated fatty acids, the low lysine:arginine ratio, and the presence of other bioactive molecules (such as fiber, phytosterols, vitamin and other antioxidants, and minerals) make the addition of nuts to healthy diets a useful tool for the prevention of cardiovascular heart diseases.
Ros, E., J. Mataix, 2006. Fatty acid composition of nuts – implications for cardiovascular health. British Journal of Nutrition. 96, Suppl. 2, S29-S35.
It is well established that, due to their high content of saturated fatty acids (SFA), the intake of meat and meat products is strongly associated with elevated blood cholesterol concentrations and an increased risk of hypertension, diabetes and cardiovascular diseases. Conversely, the intake of foods rich in unsaturated fatty acids, such as those contained in most vegetable fats and oils and oily fish, is associated with improved lipid profiles, a lower potency of intermediate biomarkers of atherosclerosis and lesser incidence of cardiovascular diseases. There are persuasive evidences that dietary substitution of monounsaturated fatty acids (MUFA) or n-6 polyunsaturated fatty acids (PUFA) for SFA lowers blood cholesterol and may have beneficial effects on inflammation, thrombosis, and vascular reactivity. MUFA may have an advantage over PUFA because enrichment of lipoprotein lipids with MUFA increases their resistance to oxidation. Marine n-3 PUFA have a number of anti-atherosclerotic effects, including anti-arrhythmic properties and, at relatively high doses, reduce serum triglycerides. These effects appear to be shared in part by vegetable n-3 PUFA. Nuts are natural foods rich in unsaturated fatty acids; most nuts contain substantial amounts of MUFA, while walnuts are especially rich in both n-6 and n-3 PUFA. Healthy fats in nuts contribute to the beneficial effects of frequent nut intake observed in epidemiological studies (prevention of coronary heart disease, diabetes, and sudden death) and in short-term feeding trials (cholesterol lowering, LDL resistance to oxidation, and improved endothelial function).
Kurlandsky, S.B., K.S. Stote, 2006. Cardioprotective effects of chocolate and almond consumption in healthy women. Nutr. Res. 26:509-516.
The primary objective of this study was to identify potentially synergistic or additive effects of combining consumption of dark chocolate with almonds as part of a low-fat diet on circulating levels of serum lipids and inflammatory markers: intercellular adhesion molecule (ICAM), vascular adhesion molecule, and high-sensitivity C-reactive protein. A 6-week, 4-armed parallel design was used; 49 healthy normocholesterolemic women participated. Subjects were randomized to 1 of 3 treatments: chocolate (41 g/d), almonds (60 g/d), chocolate and almonds, or control (no chocolate or almonds). All subjects followed the National Cholesterol Education Program Therapeutic Lifestyle Changes diet. All subjects improved dietary intakes in accordance with guidelines, and no subjects gained or lost weight. Serum cholesterol concentrations showed no changes after 6 weeks; however, triacylglycerol levels were reduced by approximately 21%, 13%, 19%, and 11% ( P < .05), in the chocolate, almond, chocolate and almond, and control groups, respectively. Circulating ICAM levels decreased significantly by 10% in the treatment group consuming chocolate only (P = .027). No significant changes were observed for vascular adhesion molecule and high-sensitivity C-reactive protein levels in any treatment group. No synergistic or additive effects were observed when both products were consumed. In conclusion, consumption of chocolate and almonds as part of the Therapeutic Lifestyle Changes diet for 6 weeks showed no harmful effects in healthy women; all dietary modifications improved serum triacylglycerol levels, and consumption of chocolate reduced levels of circulating ICA
