Casas-Agustench, P., P. Lopez-Uriarte, M. Bullo’, E. Ros, J.J. Cabre’-Vila, J. Salas-Salvado’, 2009. Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome. Nutrition, Metabolism & Cardiovascular Diseases. doi:10.1016/j.numecd.2009.08.005.
Background and aims: Knowledge of the effect of nut consumption on metabolic syndrome (MetS) components is limited. We assessed the effects of nut intake on adiposity, serum lipids, insulin resistance, and inflammatory biomarkers in patients with MetS. Methods and results: In a randomized, parallel-group, 12-week feeding trial, 50 patients with MetS were given recommendations for a healthy diet with or without supplementation with 30 g/day of raw nuts (15 g walnuts, 7.5 g almonds and 7.5 g hazelnuts) (Nut and Control diet groups, respectively). Adiposity measures, serum lipids, insulin, Homeostasis Model Assessment (HOMA), interleukin-6 (IL-6) and other inflammatory biomarkers, and 48-h fecal fat were determined basally and at study’s completion. Moderate weight loss, decreased adiposity, and lower blood pressure occurred similarly after both diets. The Control, but not the Nut diet, was associated with significant (P < 0.05) reduction of LDL-cholesterol, with mean changes of -0.36 versus -0.13 mmol/L, respectively (between-group differences, P=0.154). The Nut diet reduced fasting insulin by 2.60 µU/mL (95% CI, -4.62 to -0.59) and HOMA-insulin resistance by 0.72 (-1.28 to -0.16) (P < 0.05 versus Control diet; both). Among inflammatory markers, the Nut diet resulted in changes of median plasma IL-6 of -1.1 ng/L (-2.7 to -0.1; P=0.035 versus Control diet), but adjustment for weight loss attenuated the significance of the association. Stool fat decreased with the Control diet and slightly increased with the Nut diet (P < 0.05 for between-group differences). Conclusion: Patients with MetS show decreased lipid responsiveness but improved insulin sensitivity after daily intake of 30 g of mixed nuts.
Cassady, B.A., J.H. Hollis, A.D. Fulford, R.V. Considine, R.D. Mattes, 2009. Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response. Am. J. Clin. Nutr. 89:794-800.
Background: Epidemiologic and clinical data indicate that nuts can be incorporated into the diet without compromising body weight. This has been attributed to strong satiety properties, increased resting energy expenditure, and limited lipid bioaccessibility. Objective: The role of mastication was explored because of evidence that the availability of nut lipids is largely dependent on the mechanical fracture of their cell walls. Design: In a randomized, 3-arm, crossover study, 13 healthy adults (body mass index, in kg/m2: 23.1 ± 0.4) chewed 55 g almonds 10, 25, or 40 times. Blood was collected and appetite was monitored during the following 3 h. Over the next 4 d, all foods were provided, including 55 g almonds, which were consumed under the same chewing conditions. Complete fecal samples were collected. Results: Hunger was acutely suppressed below baseline (P < 0.05), and fullness was elevated above baseline longer (P < 0.05) after 40 chews than after 25 chews. Two hours after consumption, fullness levels were significantly lower and hunger levels were significantly higher after 25 chews than after 10 and 40 chews (P < 0.05). Initial postingestive glucagon-like peptide-1 concentrations were significantly lower after 25 chews than after 40 chews (P < 0.05), and insulin concentrations declined more rapidly after 25 and 40 chews than after 10 chews (both P < 0.05). Fecal fat excretion was significantly higher after 10 chews than after 25 and 40 chews (both P < 0.05). All participants had higher fecal energy losses after 10 and 25 chews than after 40 chews (P < 0.005). Conclusion: The results indicate important differences in appetitive and physiologic responses to masticating nuts and likely other foods and nutrients. This trial was registered at clinicaltrials.gov as NCT00768417.
Monagas, M., I. Garrido, R. Lebron-Aguilar, M.C. Gomez-Cordoves, A. Rybarczyk, R. Amarowicz, B.A. Bartolome, 2009. Comparative flavan-3-ol profile and antioxidant capacity of roasted peanut, hazelnut, and almond skins. J. Agric. Food Chem., 57(22):10590-10599.
In the present study, the flavan-3-ol composition and antioxidant capacity of roasted skins obtained from the industrial processing of three commonly consumed tree nuts (i.e., peanuts, hazelnuts, and almonds), as well as fractions containing low and high molecular weight (LMW and HMW) flavan-3-ols, were studied with the aim of assessing their potential as a source of flavonoids. Roasted peanut and hazelnut skins presented similar total phenolic contents, much higher than that of almond skins, but their flavan-3-ol profiles, as determined by LC-ESI-MS and MALDI-TOF MS, differed considerably. Peanut skins were low in monomeric flavan-3-ols (19%) in comparison to hazelnut (90%) and almond (89%) skins. On the other hand, polymeric flavan-3-ols in peanut and almond skins occurred as both A- and B-type proanthocyanidins, but in peanuts the A forms (up to DP12) were predominant, whereas in almonds the B forms (up to DP8) were more abundant. In contrast, hazelnuts were mainly constituted by B-type proanthocyanidins (up to DP9). The antioxidant capacity as determined by various methods (i.e., total antioxidant capacity, ORAC, DPPH test, and reducing power) was higher for whole extracts from roasted hazelnut and peanut skins than for almond skins; however, the antioxidant capacities of the HMW fraction of the three types of nut skins were equivalent despite their different compositions and DPs. Nevertheless, the large variation in flavan-3-ol concentration, structural composition, type of interflavan linkage, and DP found among the three types of nut skins suggests large difference in their expected in vivo biological activities.
Alasalvar, C., F. Shahidi, 2009. Natural antioxidants in tree nuts. Eur. J. Lipid Sci. Technol. 111:1056-1062
The levels of natural antioxidants and phytochemicals present in tree nuts are reported. Where possible, the health claims by Food and Drug Administration and European Food Safety Authority and health effects of tree nuts are provided. The content and recommended dietary allowances of nutrient antioxidants (such as vitamins A, C, E, and the mineral selenium) present in various tree nuts are compared. Antioxidant activity and phytochemicals present among tree nuts have been thoroughly reviewed. Research findings from over 65 references, many of which have been published within the last 10 years, have been compiled and reported.
Raw, D., B. Lockwood, 2009. The health benefits of nuts. NUTRAfoods. 8(3)7-14.
Overall, nuts can belp reduce the certain risk factors associated with CVD and other chronic diseases, helping to prevent disease and promote health.
Li, T.Y., A.M. Brennan, N.M. Wedick, C. Mantzoros, N. Rifai, F.B. Hu, 2009. Regular Consumption of Nuts Is Associated with a Lower Risk of Cardiovascular Disease in Women with Type 2 Diabetes. J. Nutr.139:1333-1338.
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 2-4 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: 0.36-0.89). 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.
Zaveri, S., S. Drummond, 2009. The effect of including a conventional snack (cereal bar) and a nonconventional snack (almonds) on hunger, eating frequency, dietary intake and body weight. J Hum Nutr Diet, 22:461-468.
Background: With the increasing prevalence of being overweight and obesity, dietary strategies to curb hunger levels and increase satiety at lower energy intakes are sought. The frequency of eating and type of snack may influence total energy intake. The present study aimed to assess the impact of providing either a conventional snack (cereal bar) or a nonconventional snack (almonds) on eating frequency, hunger rating, dietary intake, body weight and blood lipids. Methods: Forty-five healthy men (aged 25-50 years, body mass index = 25-35 kg m-2 were recruited and allocated to a control, cereal bar or almond snack group. Two packets of cereal bars and almonds were introduced for 12 weeks to the cereal bar group and the almond snack group, respectively. Dietary intakes and eating frequency were assessed by 4-day unweighed diet diaries; visual analogue scales were used to assess hunger ratings; and fasting blood parameters (i.e. glucose, insulin, total cholesterol, triglycerides, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol) were measured at baseline, 6 and 12 weeks. In addition, anthropometric measures (height, weight, skinfold thickness, waist and hip circumference) were measured at baseline, 6 and 12 weeks. Results: The present study found no significant change in the eating frequency within groups at 12 weeks. However, the almond snack group had a significantly higher eating frequency than the control group (P ≤ 0.05) and cereal bar group (P ≤ 0.01). This did not result in higher energy intake, body weight or percentage body fat in the almond snack group. Conclusion: The present study demonstrated that snacking on almonds, in comparison to cereal bars, promoted a higher eating frequency, but not a higher energy intake. Advice to snack on either almonds or cereal bars did not result in weight gain, suggesting that energy compensation took place.
Urpi-Sarda, M., I. Garrido, M. Monagas, C. Gomez-Cordoves, A. Medina-Remon, C. Andres-Lacueva, B. Bartolomei, 2009. Profile of plasma and urine metabolites after the intake of almond [prunus dulcis (mill.) D.A. Webb] polyphenols in humans. J. Agric. Food Chem. 57:10134-10142.
Nut skins are considered to be a rich source of polyphenols and may be partially responsible for the numerous health effects associated with nut consumption. However, more bioavailability studies of nut skin polyphenols are needed to understand the health effects derived from nut consumption. The aim of the present study was to determine the profiles of both phase II and microbial-derived phenolic metabolites in plasma and urine samples before and after the intake of almond skin polyphenols by healthy human subjects (n = 2). Glucuronide, O-methyl glucuronide, sulfate, and O-methyl sulfate derivatives of (epi) catechin, as well as the glucuronide conjugates of naringenin and glucuronide and sulfate conjugates of isorhamnetin, were detected in plasma and urine samples after consumption of almond skin polyphenols. The main microbial-derived metabolites of flavanols, such as 5-(dihydroxyphenyl)-γ-valerolactone and 5-(hydroxymethoxyphenyl)-γ-valerolaclone, were also detected in their glucuronide and sulfate forms. In addition, numerous metabolites derived from further microbial degradation of hydroxyphenylvalerolactones, including hydroxyphenylpropionic, hydroxyphenylacetic, hydroxycinnamic, hydroxybenzoic, and hydroxy hippuric acids, registered major changes in urine after the consumption of almond skin polyphenols. The urinary excretion of these microbial metabolites was estimated to account for a larger proportion of the total polyphenol ingested than phase II metabolites of (epi) catechin, indicating the important role of intestinal bacteria in the metabolism of highly polymerized almond skin polyphenols. To the authors’ knowledge this study constitutes the most complete report of the absorption of almond skin polyphenols in humans.
Ros, E., 2009. Nuts and novel biomarkers of cardiovascular disease. Am J Clin Nutr. 89(suppl):1649S-56S.
Nuts are energy-dense foods, rich in total fat and unsaturated fatty acids. The favorable fatty acid profile probably contributes to the beneficial effects of nut consumption observed in epidemiologic studies (prevention of coronary heart disease and diabetes) and feeding trials (cholesterol lowering). Besides fat, the complex matrices of nuts contain many bioactive compounds: vegetable protein, fiber, minerals, tocopherols, and phenolic compounds. By virtue of their unique composition, nuts are likely to benefit newer cardiovascular risk biomarkers, such as LDL oxidizability, soluble inflammatory molecules, and endothelial dysfunction. Protection of LDL oxidation by nut intake has been documented in some, but not all, clinical studies. In one study, feeding one daily serving of mixed nuts was associated with lower oxidized LDL concentrations. Regarding inflammation, cross-sectional studies have shown that nut consumption is associated with lower concentrations of circulating inflammatory molecules and higher plasma adiponectin, a potent anti-inflammatory adipokine. Clinical studies with nuts have documented reduced inflammatory cytokine concentrations but no consistent changes of C-reactive protein. Only walnuts have been formally tested for effects on endothelial function. After both walnut diets and single walnut meals, favorable vasoreactivity changes have been observed. Walnut consumption also reduced expression of endothelin 1, a potent endothelial activator, in an animal model of accelerated atherosclerosis. Beneficial effects on vascular reactivity may be ascribed to several constituents of walnuts: L-arginine, the precursor of nitricoxide, a-linolenic acid, and phenolic antioxidants. Although more studies are warranted, the emerging picture is that nut consumption beneficially influences cardiovascular risk beyond cholesterol lowering.
Richardson, D.P., A. Astrup, A. Cocaul, P. Ellis, 2009. The nutritional and health benefits of almonds: a healthy food choice. Food Science and Technology Bulletin: Functional Foods. 6(4):41-50.
Over the last decade, the research on the effects of almonds on reducing blood cholesterol levels and reduction of risk of heart disease has grown significantly. Emerging research on almonds also shows promising health benefits linked to body weight control and diabetes. Almonds naturally contain high levels of monounsaturated and polyunsaturated fatty acids, protein and dietary fiber, as well as a variety of essential nutrients including vitamin E and several trace elements. Almonds are very low in sodium and high in potassium, and they contain a range of phytoprotective constituents. The available evidence also indicates that weight gain may not be a concern when nuts are consumed in moderation, and that regular consumption of nuts can be recommended in the context of a healthy balanced diet.
