O’Neil, C.E., D.R. Keast, T.A. Nicklas, V.L. Fulgoni, 2012. Out-of-hand nut consumption is associated with improved nutrient intake and health risk markers in US children and adults: National Health and Nutrition Examination Survey 1999-2004. Nutrition Research. 32:185-194.
The purpose of this study was to determine the association of out-of-hand nut (OOHN) consumption with nutrient intake, diet quality, and the prevalence of risk factors for cardiovascular disease and metabolic syndrome. Data from 24-hour recalls from individuals aged 2+ years (n = 24,385) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. The population was divided into children aged 2 to 11, 12 to 18, and adults 19+ years, and each group was dichotomized into OOHN consumers and nonconsumers. Out-of-hand nut consumers were defined as those individuals consuming ¼ oz of nuts or more per d. Means, standard errors, and covariate-adjusted analyses of variance were determined using appropriate sample weights. Diet quality was determined using the Healthy Eating Index-2005. Significance was set at P < .05. The percent of OOHN consumers increased with age: 2.1% ± 0.3%, 2.6% ± 0.3%, 6.5% ± 0.5%, and 9.6% ± 0.5% those aged 2 to 11, 12 to 18, 19 to 50, and 51+ years, respectively. The 2 latter groups were combined into a single group of consumers aged 19+ years for subsequent analyses. Consumers of OOHN from all age groups had higher intakes of energy, monounsaturated and polyunsaturated fatty acids, dietary fiber, copper, and magnesium and lower intakes of carbohydrates, cholesterol, and sodium than did nonconsumers. Diet quality was higher in OOHN consumers of all age groups. In children aged 2 to 11 years, consumers had a higher prevalence of overweight/obesity. In those aged 12 to 18 years, weight and percent overweight were lower in consumers. Adult consumers had higher high-density lipoprotein cholesterol, red blood cell folate, and serum folate levels and lower insulin, glycohemoglobin, and C-reactive protein levels than did nonconsumers. Adult consumers also had a 19% decreased risk of hypertension and a 21% decreased risk of low high-density lipoprotein cholesterol levels. Data suggested that OOHN consumption was associated with improved nutrient intake, diet quality, and, in adults, a lower prevalence of 2 risk factors for metabolic syndrome. Consumption of OOHN, as part of a healthy diet, should be encouraged by health professionals.
O’Neil, C.E., D.R. Keast, T.A. Nicklas, V.L. Fulgoni, 2011. Nut consumption is associated with decreased health risk factors for cardiovascular disease and metabolic syndrome in U.S. adults: NHANES 1999–2004. Journal of the American College of Nutrition. 30(6):502–510.
Background: Few recent epidemiologic studies have assessed the effect that nut consumption (including tree nuts and peanuts) has on health risks, including metabolic syndrome (MetS). Objective: This study compared the health risk for cardiovascular disease, type 2 diabetes, and MetS of nut consumers with that of nonconsumers. Design: Adults 19+ years (n = 13,292) participating in the 1999–2004 National Health and Nutrition Examination Survey were used. Intake from 24-hour recalls was used to determine intake. Nut/tree nut consumers consumed ≥¼ ounce per day. Covariate-adjusted means, standard errors, and prevalence rates were determined for the nut consumption groups. Results: The prevalence of nut consumers was 18.6% ± 0.7% and 21.0% ± 0.9% in those 19–50 years and 51 years and older, respectively. Nut consumption was associated with a decreased body mass index (27.7 kg/m2 ± 0.2 vs 28.1 ± 0.1 kg/m2, p<0.05), waist circumference (95.6 ± 0.4 cm vs 96.4 ± 0.3 cm, p < 0.05), and systolic blood pressure (121.9 ± 0.4 mmHg vs 123.20 ± 0.3 mmHg, p < 0.01) compared with nonconsumers. Tree nut consumers also had a lower weight (78.8 ± 0.7 kg vs 80.7 ± 0.3 kg, p < 0.05). Nut consumers had a lower percentage of two risk factors for MetS: hypertension (31.5% ± 1.0% vs 34.2% ± 0.8%, p < 0.05) and low high density lipoprotein-cholesterol (HDL-C) (29.6% ± 1.0% vs 34.8% ± 0.8%, p < 0.01). Tree nut consumers had a lower prevalence of four risk factors for MetS: abdominal obesity (43.6% ± 1.6% vs 49.5% ± 0.8%, p < 0.05), hypertension (31.4% ± 1.2% vs 33.9% ± 0.8%, p < 0.05), low HDL-C (27.9% ± 1.7% vs 34.5% ± 0.8%, p < 0.01), high fasting glucose (11.4% ± 1.4% vs 15.0% ± 0.7%, p < 0.05), and a lower prevalence of MetS (21.2% ± 2.1% vs 26.6% ± 0.7%, p < 0.05). Conclusion: Nut/tree nut consumption was associated with a decreased prevalence of selected risk factors for cardiovascular disease, type 2 diabetes, and MetS.
Bolling, B.W., C.-Y. O. Chen, D.L. McKay, J.B. Blumberg, 2011. Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts. Nutrition Research Reviews 24:244–275
Tree nuts contain an array of phytochemicals including carotenoids, phenolic acids, phytosterols and polyphenolic compounds such as flavonoids, proanthocyanidins (PAC) and stilbenes, all of which are included in nutrient databases, as well as phytates, sphingolipids, alkylphenols and lignans, which are not. The phytochemical content of tree nuts can vary considerably by nut type, genotype, pre- and post-harvest conditions, as well as storage conditions. Genotype affects phenolic acids, flavonoids, stilbenes and phytosterols, but data are lacking for many other phytochemical classes. During the roasting process, tree nut isoflavones, flavanols and flavonols were found to be more resistant to heat than the anthocyanins, PAC and trans-resveratrol. The choice of solvents used for extracting polyphenols and phytosterols significantly affects their quantification, and studies validating these methods for tree nut phytochemicals are lacking. The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemopreventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes. While tree nut phytochemicals are bioaccessible and bioavailable in humans, the number of intervention trials conducted to date is limited. The objectives of the present review are to summarize tree nut: (1) phytochemicals; (2) phytochemical content included in nutrient databases and current publications; (3) phytochemicals affected by pre- and post-harvest conditions and analytical methodology; and (4) bioactivity and health benefits in humans.
Jenkins, D.J.A., C.W.C. Kendall, M.S. Banach, K. Srichaikul, E. Vidgen, S. Mitchell, T. Parker, S. Nishi, B. Bashyam, R. de Souza, C. Ireland, R.G. Josse, 2011. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care. 34(8):1706-11.
OBJECTIVE: Fat intake, especially monounsaturated fatty acid (MUFA), has been liberalized in diabetic diets to preserve HDL cholesterol and improve glycemic control, yet the exact sources have not been clearly defined. Therefore, we assessed the effect of mixed nut consumption as a source of vegetable fat on serum lipids and HbA1c in type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 117 type 2 diabetic subjects were randomized to one of three treatments for 3 months. Supplements were provided at 475 kcal per 2,000-kcal diet as mixed nuts (75 g/day), muffins, or half portions of both. The primary outcome was change in HbA1c. RESULTS: The relative increase in MUFAs was 8.7% energy on the full-nut dose compared with muffins. Using an intention-to-treat analysis (n = 117), full-nut dose (mean intake 73 g/day) reduced HbA1c (−0.21% absolute HbA1c units, 95% CI −0.30 to −0.11, P < 0.001) with no change after half-nut dose or muffin. Full-nut dose was significantly different from half-nut dose (P = 0.004) and muffin (P = 0.001), but no difference was seen between half-nut dose and muffins. LDL cholesterol also decreased significantly after full-nut dose compared with muffin. The LDL cholesterol reduction after half-nut dose was intermediate and not significantly different from the other treatments. Apolipoprotein (apo) B and the apoB:apoA1 ratio behaved similarly. Nut intake related negatively to changes in HbA1c (r = −0.20, P = 0.033) and LDL cholesterol (r = −0.24, P = 0.011). CONCLUSIONS: Two ounces of nuts daily as a replacement for carbohydrate foods improved both glycemic control and serum lipids in type 2 diabetes.
Hudthagosol, C., E. H. Haddad, K. McCarthy, P. Wang, K. Oda, J. Sabaté, 2011. Pecans acutely increase plasma postprandial antioxidant capacity and catechins and decrease LDL oxidation in humans. J. Nutr.141(1):56-62.
Bioactive constituents of pecan nuts such as γ-tocopherol and flavan-3-ol monomers show antioxidant properties in vitro, but bioavailability in humans is not known. We examined postprandial changes in plasma oxygen radical absorbance capacity (ORAC) and in concentrations of tocopherols, catechins, oxidized LDL, and malondialdehyde (MDA) in response to pecan test meals. Sixteen healthy men and women (23–44 y, BMI 22.7 ± 3.4) were randomly assigned to 3 sequences of test meals composed of whole pecans, blended pecans, or an isocaloric meal of equivalent macronutrient composition but formulated of refined ingredients in a crossover design with a 1-wk washout period between treatments. Blood was sampled at baseline and at intervals up to 24 h postingestion. Following the whole and blended pecan test meals, plasma concentrations of γ-tocopherols doubled at 8 h (P < 0.001) and hydrophilic- and lipophilic-ORAC increased 12 and 10% at 2 h, respectively. Post whole pecan consumption, oxidized LDL decreased 30, 33, and 26% at 2, 3, and 8 h, respectively (P < 0.05), and epigallocatechin-3-gallate concentrations at 1 h (mean ± SEM; 95.1 ± 30.6 nmol/L) and 2 h (116.3 ± 80.5 nmol/L) were higher than at baseline (0 h) and after the control test meal at 1 h (P < 0.05). The postprandial molar ratio of MDA:triglycerides decreased by 37, 36, and 40% at 3, 5, and 8 h, respectively (P < 0.05), only when whole and blended pecan data were pooled. These results show that bioactive constituent of pecans are absorbable and contribute to postprandial antioxidant defenses.
Sabate´, J., K. Oda, E. Ros, 2010. Nut Consumption and Blood Lipid Levels A Pooled Analysis of 25 Intervention Trials. Arch Intern Med. 170(9):821-827.
Background: Epidemiological studies have consistently associated nut consumption with reduced risk for coronary heart disease. Subsequently, many dietary intervention trials investigated the effects of nut consumption on blood lipid levels. The objectives of this study were to estimate the effects of nut consumption on blood lipid levels and to examine whether different factors modify the effects. Methods: We pooled individual primary data from 25 nut consumption trials conducted in 7 countries among 583 men and women with normolipidemia and hypercholesterolemia who were not taking lipid-lowering medications. In a pooled analysis, we used mixed linear models to assess the effects of nut consumption and the potential interactions. Results: With a mean daily consumption of 67 g of nuts, the following estimated mean reductions were achieved: total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P<.001 for all) (to convert all cholesterol concentrations to millimoles per liter, multiply by 0.0259). Triglyceride levels were reduced by 20.6 mg/dL (10.2%) in subjects with blood triglyceride levels of at least 150 mg/dL (P<.05) but not in those with lower levels (to convert triglyceride level to millimoles per liter, multiply by 0.0113). The effects of nut consumption were dose related, and different types of nuts had similar effects on blood lipid levels. The effects of nut consumption were significantly modified by LDL-C, body mass index, and diet type: the lipid-lowering effects of nut consumption were greatest among subjects with high baseline LDL-C and with low body mass index and among those consuming Western diets. Conclusion: Nut consumption improves blood lipid levels in a dose-related manner, particularly among subjects with higher LDL-C or with lower BMI.
Pérez-Jiménez, J., V. Neveu, F. Vos, A. Scalbert, 2010. Identification of the 100 richest dietary sources of polyphenols: an application of the Phenol-Explorer database. European Journal of Clinical Nutrition. 64: S112–S120.
Background/Objectives: The diversity of the chemical structures of dietary polyphenols makes it difficult to estimate their total content in foods, and also to understand the role of polyphenols in health and the prevention of diseases. Global redox colorimetric assays have commonly been used to estimate the total polyphenol content in foods. However, these assays lack specificity. Contents of individual polyphenols have been determined by chromatography. These data, scattered in several hundred publications, have been compiled in the Phenol-Explorer database. The aim of this paper is to identify the 100 richest dietary sources of polyphenols using this database. Subjects/Methods: Advanced queries in the Phenol-Explorer database (www.phenol-explorer.eu) allowed retrieval of information on the content of 502 polyphenol glycosides, esters and aglycones in 452 foods. Total polyphenol content was calculated as the sum of the contents of all individual polyphenols. These content values were compared with the content of antioxidants estimated using the Folin assay method in the same foods. These values were also extracted from the same database. Amounts per serving were calculated using common serving sizes. Results: A list of the 100 richest dietary sources of polyphenols was produced, with contents varying from 15 000mg per 100g in cloves to 10mg per 100 ml in rose´ wine. The richest sources were various spices and dried herbs, cocoa products, some darkly coloured berries, some seeds (flaxseed) and nuts (chestnut, hazelnut) and some vegetables, including olive and globe artichoke heads. A list of the 89 foods and beverages providing more than 1mg of total polyphenols per serving was established. A comparison of total polyphenol contents with antioxidant contents, as determined by the Folin assay, also showed that Folin values systematically exceed the total polyphenol content values. Conclusions: The comprehensive Phenol-Explorer data were used for the first time to identify the richest dietary sources of polyphenols and the foods contributing most significantly to polyphenol intake as inferred from their content per serving.
Ros, E., L.C. Tapsell, J. Sabaté, 2010. Nuts and berries for heart health. Curr Atheroscler Rep. 12:397–406.
Nuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds, such as L-arginine, fiber, minerals, tocopherols, phytosterols, and polyphenols. By virtue of their unique composition, nuts are likely to beneficially impact heart health. Epidemiologic studies have associated nut consumption with a reduced incidence of coronary heart disease in both genders and diabetes in women. Limited evidence also suggests beneficial effects on hypertension and inflammation. Interventional studies consistently show that nut intake has a cholesterol-lowering effect and there is emerging evidence of beneficial effects on oxidative stress, inflammation, and vascular reactivity. Blood pressure, visceral adiposity, and glycemic control also appear to be positively influenced by frequent nut consumption without evidence of undue weight gain. Berries are another plant food rich in bioactive phytochemicals, particularly flavonoids, for which there is increasing evidence of benefits on cardiometabolic risk that are linked to their potent antioxidant power.
O’Neil, C.E., D. R. Keast, V.L. Fulgoni, T.A. Nicklas, 2010. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004. Asia Pac J Clin Nutr. 19(1):142-150.
Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and nutrient intake and diet quality using a nationally representative sample of adults. Adults 19+ years (y) (n=13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake was determined from 24-hour diet recalls; tree nut consumers were defined as those consuming ≥¼ ounce/day (7.09 g). Means, standard errors, and ANOVA (adjusted for covariates) were determined using appropriate sample weights. Diet quality was measured using the Healthy Eating Index-2005. Among consumers, mean intake of tree nuts/tree nut butters was 1.19 + 0.04 oz/d versus 0.01 + 0.00 oz/d for non-consumers. In this study, 5.5 ± 0.3 % of individuals 19-50 y (n=7,049) and 8.4 ± 0.6 % of individuals 51+ y (n=6,243) consumed tree nuts/tree nut butters. Mean differences (p<0.01) between tree nut consumers and non-consumers of adult shortfall nutrients were: fiber (+5.0 g/d), vitamin E (+3.7 mg AT/d), calcium (+73 mg/d), magnesium (+95 mg/d), and potassium (+260 mg/d). Tree nut consumers had lower sodium intake (-157 mg/d, p<0.01). Diet quality was significantly higher in tree nut consumers (58.0±0.4 vs. 48.5±0.3, p<0.01). Tree nut consumption was associated with a higher overall diet quality score and improved nutrient intakes. Specific dietary recommendations for nut consumption should be provided for consumers.
Kendall, C.W.C., A. Esfahani, J. Truan, K. Srichaikul, D.J.A. Jenkins, 2010. Health benefits of nuts in prevention and management of diabetes. Asia Pac J Clin Nutr. 19(1):110-116.
The effects of tree nuts on risk factors for coronary heart disease (CHD), in particular blood lipids, have been investigated in a number of studies and the beneficial effects are now recognized. The beneficial effects of nuts on CHD in cohort studies have also been clearly demonstrated. However, while there is also reason to believe the unique micro- and macronutrient profiles of nuts may help to control blood glucose levels, relatively few studies have investigated their role in diabetes control and prevention. Nuts are low in available carbohydrate, have a healthy fatty acid profile, and are high in vegetable protein, fiber and magnesium. Acute feeding studies indicate that when eaten alone nuts have minimal effects on raising postprandial blood glucose levels. In addition, when nuts are consumed with carbohydrate rich foods, they blunt the postprandial glycemic response of the carbohydrate meal. Despite the success of these acute studies, only a limited number of trials have been conducted with nuts in type 2 diabetes. These studies have either been of insufficient duration to observe changes in HbA1c, as the standard measure of glycemic control, or have been underpowered. Therefore, more long-term clinical trials are required to examine the role of nuts on glycemic control in patients with prediabetes and diabetes. Overall, there are good reasons to justify further exploration of the use of nuts in the prevention of diabetes and its microand macrovascular complications.
