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Research Nut: Almonds

Nut consumption is associated with a healthy dietary pattern in military men.

Mullie, M., P. Clarys, 2012. Nut consumption is associated with a healthy dietary pattern in military men. Food and Nutrition Sciences. 3:1048-1054.

The objective of the research was to determine the relation between nut consumption and dietary patterns described by Healthy Eating Index, Mediterranean Diet Score and principal component analysis. In a cross-sectional study, 1852 military men were contacted by mail. Using food-frequency questionnaires, nut consumption was recorded and stratified in weekly versus less than weekly. Three dietary indices were calculated and stratified in quintiles. For principal component analysis, the healthiest dietary pattern rich in fruits and vegetables was selected as Healthy Dietary Pattern. The highest quintiles of Healthy Eating Index, Mediterranean Diet Score and Healthy Dietary Pattern were systematically associated with the highest weekly consumption of nuts. The highest quintiles were also associated with the lowest intake of saturated fat, i.e. between 10 and 12 energy-percent compared with 17 to 19 energy-percent for the lowest quintiles. The mean daily nut consumption was less than 6 g a day, which is beneath the recommended quantity for cardiovascular protection. Nut consumption was associated with the healthiest dietary pattern, independently of the used method to determine the dietary pattern. Regular nut consumption seems to be a component of a cluster of several healthy behaviors.

Urolithins are the main urinary microbial-derived phenolic metabolites discriminating a moderate consumption of nuts in free-living subjects with diagnosed metabolic syndrome.

Tulipani, S., M. Urpi-Sarda, R. Garcıá -Villalba, M. Rabassa, P. López-Uriarte, M. Bulló, O. Jáuregui, F. Tomás-Barberán, J. Salas-Salvado,́ J. Carlos Espıń, C. Andrés-Lacueva, 2012. Urolithins are the main urinary microbial-derived phenolic metabolites discriminating a moderate consumption of nuts in free-living subjects with diagnosed metabolic syndrome. J. Agric. Food Chem. doi.org/10.1021/jf301509w.

Walnuts (Juglans regia L.), hazelnuts (Corylus avellana L.), and almonds (Prunus dulcis Mill.) are rich sources of ellagitannins and proanthocyanidins. Gut microbiota plays a crucial role in modulating the bioavailability of these high molecular weight polyphenols. However, to date there are no studies evaluating the capacity to produce nut phenolic metabolites in subjects with metabolic syndrome (MetS), a pathology associated with an altered gut bacterial diversity. This study applied a LC-MS targeted approach to analyze the urinary excretion of nut phenolic metabolites in MetS subjects following 12 weeks of nut consumption, compared to sex- and age-matched individuals given a nut-free control diet. Metabolites were targeted in both hydrolyzed and nonhydrolyzed urine by LC-PDA-QqQ-MS/MS analysis, and identification of metabolites lacking available standards was confirmed by LC-ESI-ITD-FT-MS. Ellagitannin-derived urolithins A and B significantly increased after the nutenriched-diet, urolithins C and D were also detected, and a complex combination of urolithin-conjugated forms was observed in nonhydrolyzed urine, confirming an extensive phase II metabolism after absorption. In contrast, no significant increases in proanthocyanidin microbial metabolites were observed in urine following nut consumption. Because the intestinal microbiota of the subjects in this study could catabolize ellagitannins into a wide range of urolithins, further research is strongly warranted on the in vivo potential of these microbial metabolites in reducing cardiometabolic risk.

Health benefits of almonds beyond cholesterol reduction.

Kamil, A., C.-Y. O. Chen, 2012. Health benefits of almonds beyond cholesterol reduction. J. Agric. Food Chem. 60:6694−6702.

Almonds are rich in monounsaturated fat, fiber, α-tocopherol, minerals such as magnesium and copper, and phytonutrients, albeit being energy-dense. The favorable fat composition and fiber contribute to the hypocholesterolemic benefit of almond consumption. By virtue of their unique nutrient composition, almonds are likely to benefit other modifiable cardiovascular and diabetes risks, such as body weight, glucose homeostasis, inflammation, and oxidative stress. This paper briefly reviews the nutrient composition and hypocholesterolemic benefits; the effects of almond consumption on body weight, glucose regulation, oxidative stress, and inflammation, based on the data of clinical trials, will then be discussed. Although more studies are definitely warranted, the emerging evidence supports that almond consumption beneficially influences chronic degenerative disease risk beyond cholesterol reduction, particularly in populations with metabolic syndrome and type 2 diabetes mellitus.

Nuts for diabetes prevention and management.

Kamil, A., C.-Y. O. Chen, 2012. Nuts for diabetes prevention and management. Journal of Food and Drug Analysis. 20(Suppl.1): 323-327.

Type 2 diabetes mellitus is an important preventable disease and a growing public health problem. Epidemiologic and clinical studies suggest that healthy eating, physical activity, and BW control are the main driving forces to reduce diabetes risk. Owing to their low available carbohydrate content, favorable fat and protein profile as well as phytonutrient content, nut consumption has been associated with a reduced risk of development and management of diabetes. Nuts, by virtue of its cardioprotective actions, have also been shown to reduce biomarkers of risk factors for diabetic complications. Although more studies are warranted, the emerging picture is that nut consumption beneficially influences diabetes risk and management beyond blood glucose control.

A randomized trial of the effects of an almond-enriched, hypocaloric diet in the treatment of obesity.

Foster, G.D., K.L. Shantz, S.S.Vander Veur, T.L. Oliver, M.R. Lent, A. Virus, P.O. Szapary, D.J. Rader, B.S. Zemel, A. Gilden-Tsai, 2012. A randomized trial of the effects of an almond-enriched, hypocaloric diet in the treatment of obesity. Am J Clin Nutr. 96:249–54.

Background: Increased consumption of nuts has been advocated because of their health benefits, but the role of nuts in the treatment of obesity is unclear given their high energy density. Objective: This study was designed to evaluate the effects of a hypocaloric, almond-enriched diet (AED) compared with a hypocaloric nut-free diet (NFD) on body weight and cardiovascular disease risk factors in the context of an 18-mo behavioral weight-management program. Design: Overweight and obese individuals [n = 123; age = 46.8 y, BMI (in kg/m2) = 34.0] were randomly assigned to consume an AED or NFD and instructed in traditional behavioral methods of weight control. Anthropometric and metabolic measurements were made at baseline, 6 mo, and 18 mo. Results: Those in the AED group lost slightly but significantly less weight than did those in the NFD group at 6 mo (25.5 compared with 27.4 kg; P = 0.04), but there were no differences at 18 mo. No significant differences in body composition were found between the groups at 6 or 18 mo. The AED, compared with the NFD, was associated with greater reductions in total cholesterol (P = 0.03), total:HDL cholesterol (P = 0.02), and triglycerides (P = 0.048) at 6 mo, and no differences were observed between the groups at 18 mo. Conclusions: The AED and NFD groups  experienced clinically significant and comparable weight loss at 18 mo. Despite smaller weight loss in the AED group at 6 mo, the AED group experienced greater improvements in lipid profiles.

Discrepancy between the Atwater factor predicted and empirically measured energy values of almonds in human diets.

Novotny, J.A., S.K. Gebauer, D.J. Baer, 2012. Discrepancy between the Atwater factor predicted and empirically measured energy values of almonds in human diets. Am J Clin Nutr. 96:296–301. 

Background: The energy content of foods is primarily determined by the Atwater factors, which may not be accurate for certain food groups. Nuts are a food group for which substantial evidence suggests that the Atwater factors may be poorly predictive. Objective: A study was conducted to determine the energy value of almonds in the human diet and to compare the measured energy value with the value calculated from the Atwater factors. Design: Eighteen healthy adults consumed a controlled diet or an almond-containing diet for 18 d. Three treatments were administered to subjects in a crossover design, and diets contained 1 of 3 almond doses: 0, 42, or 84 g/d. During the final 9 d of the treatment period, volunteers collected all urine and feces, and samples of diets, feces, and urine were analyzed for macronutrient and energy contents. The metabolizable energy content of the almonds was determined. Results: The energy content of almonds in the human diet was found to be 4.6 6 0.8 kcal/g, which is equivalent to 129 kcal/28-g serving. This is significantly less than the energy density of 6.0–6.1 kcal/g as determined by the Atwater factors, which is equivalent to an energy content of 168–170 kcal/serving. The Atwater factors, when applied to almonds, resulted in a 32% overestimation of their measured energy content. Conclusion: This study provides evidence for the inaccuracies of the Atwater factors for certain applications and provides a rigorous method for determining empirically the energy value of individual foods within the context of a mixed diet.

The beneficial effects of tree nuts on the aging brain.

Carey, A.N., S.M. Poulose, B. Shukitt-Hale, 2012. The beneficial effects of tree nuts on the aging brain. Nutrition and Aging. 1:55–67.

Dietary patterns may play an important role in protecting the brain from the cellular and cognitive dysfunction associated with the aging process and neurodegenerative diseases. Tree nuts are showing promise as possible dietary interventions for age-related brain dysfunction. Tree nuts are an important source of essential nutrients, like vitamin E, folate, and fiber. Tree nuts also contain a variety of components, such as phytochemicals like flavonoids, proanthocyanidins, and phenolic acids, as well as monounsaturated and omega-3 and omega-6 polyunsaturated fatty acids that have the potential to combat age-related brain dysfunction. Evidence is accumulating that suggests that tree nuts and their bioactive constituents have the potential to reduce oxidative stress and inflammation, as indicated by decreased lipid peroxidation in vivo and reduced production of the free radical nitric oxide and the pro-inflammatory cytokine tumor necrosis factor-alpha in vitro. Also, tree nut consumption might have the ability to mitigate some of the cognitive decline associated with aging. Here we review the current knowledge of how the consumption of nuts may improve brain health, specifically focusing on walnuts, almonds, pistachios, and pecans.

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.

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.

Nut consumption is associated with decreased health risk factors for cardiovascular disease and metabolic syndrome in U.S. adults: NHANES 1999–2004.

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.

Adherence to the mediterranean diet in patients with type 2 diabetes mellitus and HbA1c Level.

Díez-Espino, J., P. Buil-Cosiales, M. Serrano-Martínez, E. Toledo, J. Salas-Salvadó, M.Á. Martínez-González, 2011. Adherence to the mediterranean diet in patients with type 2 diabetes mellitus and HbA1c Level. Ann Nutr Metab. 58:74–78.

Rationale and Objective: The Mediterranean diet (MeDiet) has beneficial effects on cardiovascular risk factors. We analyzed the association between adherence of a MeDiet in patients with type 2 diabetes mellitus (T2DM) and levels of HbA1c. Patients and Methods: This was a cross-sectional study in individuals with T2DM participating in the PREDIMED trial at the centre of Pamplona. Information on diet was collected with a validated 14 point scale of adherence to the MeDiet and blood samples were obtained to assess HbA1c levels. Results: We studied 383 participants with T2DM, 53.4% women (mean age 69 ± 6 years). HbA1c data were available in 262 cases (mean 6.9 ± 1.5%). Although there was a potential inverse non-significant association between adherence to MeDiet and HbA1c levels after adjusting for age and sex, it was not statistically significant. Multivariate analysis additionally adjusted for physical activity, smoking, time of evolution of the T2DM, body mass index and insulin treatment found similar findings (OR = 0.69, 95% CI 0.17–2.83). Conclusions: Although we found not enough evidence to support that a MeDiet is associated with lower levels of HbA1c in patients with T2DM, our results suggested an inverse trend. Future studies with larger sample size are necessary.