Archive

Research Area: Metabolic Syndrome

Walnuts consumed by healthy adults provide less available energy than predicted by the Atwater Factors.

Baer, D., S. Gebauer, J. Novotny, 2016. Walnuts consumed by healthy adults provide less available energy than predicted by the Atwater Factors. J Nutr. 146:1–5.

Background: Previous studies have shown that the metabolizable energy (ME) content (energy available to the body) of certain nuts is less than predicted by the Atwater factors. However, very few nuts have been investigated to date, and no information is available regarding the ME of walnuts. Objective: A study was conducted to determine the ME of walnuts when consumed as part of a typical American diet. Methods: Healthy adults (n = 18; mean age = 53.1 y; body mass index = 28.8 kg/m2) participated in a randomized crossover study with 2 treatment periods (3 wk each). The study was a fully controlled dietary feeding intervention in which the same base diet was consumed during each treatment period; the base diet was unsupplemented during one feeding period and supplemented with 42 g/d walnuts during the other feeding period. Base diet foods were reduced in equal proportions during the walnut period to achieve isocaloric food intake during the 2 periods. After a 9 d diet acclimation period, subjects collected all urine and feces for ;1 wk (as marked by a Brilliant Blue fecal collection marker) for analysis of energy content. Administered diets, walnuts, and fecal and urine samples were subjected to bomb calorimetry, and the resulting data were used to calculate the ME of the walnuts. Results: One 28-g serving of walnuts contained 146 kcal (5.22 kcal/g), 39 kcal/serving less than the value of 185 kcal/ serving (6.61 kcal/g) currently used for food labeling. The ME of the walnuts was 21% less than that predicted by the Atwater factors (P < 0.0001). Conclusion: Consistent with other tree nuts, Atwater factors overestimate the metabolizable energy value of walnuts. These results could help explain the observations that consumers of nuts do not gain excessive weight, and improve the accuracy for food labeling.

Effects of diet composition and insulin resistance status on plasma lipid levels in a weight loss intervention in women.

Le, T., S.W. Flatt, L. Natarajan, B. Pakiz, E.L. Quintana, D.D. Heath, B.K. Rana, C.L. Rock, 2016. Effects of diet composition and insulin resistance status on plasma lipid levels in a weight loss intervention in women. J Am Heart Assoc. 5(1). doi: 10.1161/JAHA.115.002771.

Background: Optimal macronutrient distribution of weight loss diets has not been established. The distribution of energy from carbohydrate and fat has been observed to promote differential plasma lipid responses in previous weight loss studies, and insulin resistance status may interact with diet composition and affect weight loss and lipid responses. Methods and Results: Overweight and obese women (n=245) were enrolled in a 1‐year behavioral weight loss intervention and randomly assigned to 1 of 3 study groups: a lower fat (20% energy), higher carbohydrate (65% energy) diet; a lower carbohydrate (45% energy), higher fat (35% energy) diet; or a walnut‐rich, higher fat (35% energy), lower carbohydrate (45% energy) diet. Blood samples and data available from 213 women at baseline and at 6 months were the focus of this analysis. Triglycerides, total cholesterol, and high‐ and low‐density lipoprotein cholesterol were quantified and compared between and within groups. Triglycerides decreased in all study arms at 6 months (P<0.05). The walnut‐rich diet increased high‐density lipoprotein cholesterol more than either the lower fat or lower carbohydrate diet (P<0.05). The walnut‐rich diet also reduced low‐density lipoprotein cholesterol in insulin‐sensitive women, whereas the lower fat diet reduced both total cholesterol and high‐density lipoprotein cholesterol in insulin‐sensitive women (P<0.05). Insulin sensitivity and C‐reactive protein levels also improved. Conclusions: Weight loss was similar across the diet groups, although insulin‐sensitive women lost more weight with a lower fat, higher carbohydrate diet versus a higher fat, lower carbohydrate diet. The walnut‐rich, higher fat diet resulted in the most favorable changes in lipid levels.

Key area: insulin resistance, lipids, walnuts/ weight management/weight, satiety,

Pairing nuts and dried fruit for cardiometabolic health.

Carughi, A., M.J. Feeney, P. Kris-Etherton, V. Fulgoni III, C.W.C. Kendall, M. Bulló, D. Webb, 2016. Pairing nuts and dried fruit for cardiometabolic health. Nutrition Journal. 15:23. doi.org/10.1186/s12937-016-0142-4.

Certain dietary patterns, in which fruits and nuts are featured prominently, reduce risk of diabetes and cardiovascular disease. However, estimated fruit consumption historically in the U.S. has been lower than recommendations. Dried fruit intake is even lower with only about 6.9 % of the adult population reporting any consumption. The 2015 Dietary Guidelines Advisory Committee identified a gap between recommended fruit and vegetable intakes and the amount the population consumes. Even fewer Americans consume tree nuts, which are a nutrient-dense food, rich in bioactive compounds and healthy fatty acids. Consumption of fruits and nuts has been associated with reduced risk of cardiometabolic disease. An estimated 5.5 to 8.4 % of U.S. adults consume tree nuts and/or tree nut butter. This review examines the potential of pairing nuts and dried fruit to reduce cardiometabolic risk factors and focuses on emerging data on raisins and pistachios as representative of each food category. Evidence suggests that increasing consumption of both could help improve Americans’ nutritional status and reduce the risk of chronic diseases.

Chronic pistachio intake modulates circulating microRNAs related to glucose metabolism and insulin resistance in prediabetic subjects.

Hernández‑Alonso, P., S. Giardina, J. Salas‑Salvadó, P. Arcelin, M. Bulló, 2016. Chronic pistachio intake modulates circulating microRNAs related to glucose metabolism and insulin resistance in prediabetic subjects. Eur. J. Nutr. doi.org/10.1007/s00394-016-1262-5.

Purpose: To assess the effects of a pistachio-enriched diet on the profile of circulating microRNAs (miRNAs) related to glucose metabolism and insulin resistance (IR). Methods: Randomized crossover clinical trial in 49 subjects with prediabetes was performed. Subjects consumed a pistachio-supplemented diet (PD, 50 % carbohydrates, 33 % fat, including 57 g/day of pistachios) and an isocaloric control diet (CD, 55 % carbohydrates and 30 % fat) for 4 months each, separated by a 2-week washout period. The plasma profile of a set of seven predefined miRNAs related to glucose and insulin metabolism was analyzed by quantitative RT-PCR. Results: After the PD period, subjects have shown significant lower circulating levels of miR-192 and miR-375 compared to CD period, whereas miR-21 nonsignificantly increased after PD compared with CD (47 vs. 2 %, P = 0.092). Interestingly, changes in circulating miR-192 and miR-375 were positively correlated with plasma glucose, insulin and HOMA-IR. Conclusion: Chronic pistachio consumption positively modulates the expression of some miRNA previously implicated on insulin sensitivity.

 

Effect of pistachio consumption on plasma lipoprotein subclasses in pre-diabetic subjects.

Hernández-Alonso, P., Salas-Salvadó J, Baldrich-Mora M, Mallol R, Correig X, Bulló M, 2015. Effect of pistachio consumption on plasma lipoprotein subclasses in pre-diabetic subjects. Nutr Metab Cardiovasc Dis. (4):396-402.

Background and Aims: Nuts have been demonstrated to improve several cardiovascular risk factors and the lipid profile in diabetic and pre-diabetic subjects. However, analysis of conventional serum lipid profiles does not completely explain the atherogenic risk associated with pre-diabetes. We therefore investigated whether chronic consumption of pistachio modifies the lipoprotein subclasses to a healthier profile in pre-diabetic subjects. Methods and Results: Randomized cross-over clinical trial in 54 subjects with pre-diabetes. Subjects consumed a pistachio-supplemented diet (PD, 50% carbohydrates, 33% fat, including 57 g/d of pistachios daily) and a control diet (CD, 55% carbohydrates, 30% fat) for 4 months each, separated by a 2-week wash-out. Diets were isocaloric and matched for protein, fiber and saturated fatty acids. Nuclear magnetic resonance (NMR) was performed to determine changes in plasma lipoprotein subclasses. Small low-density lipoprotein particles (sLDL-P) significantly decreased after pistachio consumption compared to the nut-free diet (P = 0.023). The non-high-density lipoprotein particles (non-HDL-P i.e. VLDL-P plus LDL-P) significantly decreased under the PD compared to CD (P = 0.041). The percentage of sHDL-P increased by 2.23% after the PD compared with a reduction of 0.08% after the CD (P = 0.014). Consequently, the overall size of HDL-P significantly decreased in the PD (P = 0.007). Conclusion: Chronic pistachio consumption could modify the lipoprotein particle size and subclass concentrations independently of changes in total plasma lipid profile, which may help to explain the decreased risk of cardiovascular disease and mortality associated with those individuals who frequently consumed nuts.

Nutrition attributes and health effects of pistachio nuts.

Bullo, M., M. Juanola-Falgarona, P. Herna ´ndez-Alonso, J. Salas-Salvado, 2015. Nutrition attributes and health effects of pistachio nuts. British Journal of Nutrition. 113, S79–S93.

Epidemiological and/or clinical trials have suggested that nut consumption has a beneficial impact on health outcomes such as hypertension, diabetes, CVD, cancer, other inflammatory conditions and total mortality. Nuts are nutrient-dense foods with a healthy fatty acid profile, as well as provide other bioactive compounds with recognized health benefits. Among nuts, pistachios have a lower fat and energy content and the highest levels of K, g-tocopherol, vitamin K, phytosterols, xanthophyll carotenoids, certain minerals (Cu, Fe and Mg), vitamin B6 and thiamin. Pistachios have a high antioxidant and anti-inflammatory potential. The aforementioned characteristics and nutrient mix probably contribute to the growing body of evidence that consumption of pistachios improves health. The present review examines the potential health effects of nutrients and phytochemicals in pistachios, as well as epidemiological and clinical evidence supporting these health benefits.

Effect of pistachio nut consumption on endothelial function and arterial stiffness.

Kasliwal, R.R., M. Bansal, R. Mehrotra, K.P. Yeptho, N. Trehan, 2015. Effect of pistachio nut consumption on endothelial function and arterial stiffness. Nutrition. 31(5):678–685.

Methods: In this open label, randomized parallel-group study, 60 adults with mild dyslipidemia were randomized to lifestyle modification (LSM) alone or LSM with consumption of 80 g (in-shell) pistachios (equivalent to 40 g or 1.5 oz shelled pistachios) daily for 3 mo. Biochemical parameters, brachial artery flow-mediated vasodilation (BAFMD), and carotid-femoral and brachial-ankle pulse wave velocity (cfPWV and baPWV, respectively) were measured before and after the intervention. Results: At 3 mo, there was no change in any of the clinical or biochemical parameters in the LSM group. However, the patients in the pistachio group had a significant increase in high-density lipoprotein cholesterol (HDL-C; 35.7 ± 8.8 mg/dL versus 37.8 ± 10.1 mg/dL; P = 0.04) and a reduction in low-density lipoprotein cholesterol (137.2 ± 32.6 mg/dL versus 127.6 ± 34.0 mg/dL; P = 0.02), total cholesterol (TC)-to-HDL-C ratio (5.8 ± 1.3 mg/dL versus 5.3 ± 1.1 mg/dL; P = 0.001), and fasting blood sugar (88.8 ± 7.1 mg/dL versus 86.6 ± 6.3 mg/dL; P = 0.05). Additionally, whereas LSM alone was associated with no improvement in BAFMD or PWV, individuals in the pistachio group had significant reduction in left baPWV (1261.7 ± 187.5 cm/sec versus 1192.4 ± 152.5 cm/sec; P = 0.02) and statistically nonsignificant improvement in most other parameters, including BAFMD. As a result, at 3 mo the patients in the pistachio group had lower cfPWV (770.9 ± 96.5 cm/sec versus 846.4 ± 162.0 cm/sec; P = 0.08), lower left baPWV (1192.4 ± 152.5 cm/sec versus 1326.3 ± 253.7 cm/sec; P = 0.05), and lower average baPWV (1208.2 ± 118.4 cm/sec versus 1295.8 ± 194.1 cm/sec; P = 0.08) compared with the LSM group. Two-way analysis of variance revealed significant treatment effect of pistachio consumption on cfPWV, left baPWV, average baPWV, and BAFMD (P = 0.037, 0.01, 0.07, and 0.046, respectively). Conclusions: The present study demonstrates that regular consumption of pistachio nuts not only improves glycemic and lipid parameters, but also results in improvements in vascular stiffness and endothelial function. Importantly, these improvements were seen in apparently healthy individuals and with a diet (including pistachios) and exercise regimen that every adult individual is expected to follow.

 

 

Tree Nut consumption is associated with better adiposity measures and cardiovascular and metabolic syndrome health risk factors in U.S. Adults: NHANES 2005–2010.

O’Neil, C.E., V.L. Fulgoni, T.A. Nicklas, 2015. Tree Nut consumption is associated with better adiposity measures and cardiovascular and metabolic syndrome health risk factors in U.S. Adults: NHANES 2005–2010. Nutrition Journal. 14:64. DOI 10.1186/s12937-015-0052-x

Introduction: Previous research has shown inconsistencies in the association of tree nut consumption with risk factors for cardiovascular disease (CVD) and metabolic syndrome (MetS). Objective: To determine the association of tree nut consumption with risk factors for CVD and for MetS in adults. Methods: NHANES 2005–2010 data were used to examine the associations of tree nut consumption with health risks in adults 19+ years (n = 14,386; 51 % males). Tree nuts were: almonds, Brazil nuts, cashews, filberts [hazelnuts], macadamias, pecans, pine nuts, pistachios, and walnuts. Group definitions were non-consumers < ¼ ounce/day and consumers of ≥ ¼ ounce/day tree nuts using data from 24-h dietary recalls. Means and ANOVA (covariate adjusted) were determined using appropriate sample weights. Using logistic regression, odds ratios of being overweight (OW)/obese (OB) (body mass index [BMI] >25/<30 and ≥30, respectively) and having CVRF or MetS, were determined. Results: Tree nut consumption was associated with lower BMI (p = 0.004), waist circumference (WC) (p = 0.008), systolic blood pressure (BP) (p = 0.001), Homeostatic Model Assessment—Insulin Resistance (p = 0.043), and higher high density lipoprotein-cholesterol (p = 0.022), compared with no consumption, and a lower likelihood of OB (−25 %), OW/OB (−23 %), and elevated WC (−21 %). Conclusions: Tree nut consumption was associated with better weight status and some CVRF and MetS components.

Effect of tree nuts on metabolic syndrome criteria: a systematic review and meta-analysis of randomised controlled trials.

Mejia, S.B. C.W.C. Kendall, E. Viguiliouk, L.S. Augustin, V. Ha, A.I. Cozma, A. Mirrahimi, A. Maroleanu, L. Chiavaroli, L.A. Leiter, R. J. de Souza, D.J. A. Jenkins, J.L. Sievenpiper, 2014. Effect of tree nuts on metabolic syndrome criteria: a systematic review and meta-analysis of randomised controlled trials. BMJ Open. DOI:10.1136/bmjopen-2013-004660

http://bmjopen.bmj.com/content/4/7/e004660.full?keytype=ref%5B1%5D&ijkey=wszZ1mCN44mw0KO

Objective: To provide a broader evidence summary to inform dietary guidelines of the effect of tree nuts on criteria of the metabolic syndrome (MetS). Design: We conducted a systematic review and meta-analysis of the effect of tree nuts on criteria of the MetS. Data sources: We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library (through 4 April 2014).  Eligibility criteria for selecting studies: We included relevant randomised controlled trials (RCTs) of ≥3 weeks reporting at least one criterion of the MetS. Data extraction: Two or more independent reviewers extracted all relevant data. Data were pooled using the generic inverse variance method using random effects models and expressed as mean differences (MD) with 95% CIs. Heterogeneity was assessed by the Cochran Q statistic and quantified by the I2 statistic. Study quality and risk of bias were assessed. Results: Eligibility criteria were met by 49 RCTs including 2226 participants who were otherwise healthy or had dyslipidaemia, MetS or type 2 diabetes mellitus. Tree nut interventions lowered triglycerides (MD=−0.06 mmol/L (95% CI −0.09 to −0.03 mmol/L)) and fasting blood glucose (MD=−0.08 mmol/L (95% CI −0.16 to −0.01 mmol/L)) compared with control diet interventions. There was no effect on waist circumference, high-density lipoprotein cholesterol or blood pressure with the direction of effect favouring tree nuts for waist circumference. There was evidence of significant unexplained heterogeneity in all analyses (p<0.05). Conclusions: Pooled analyses show a MetS benefit of tree nuts through modest decreases in triglycerides and fasting blood glucose with no adverse effects on other criteria across nut types. As our conclusions are limited by the short duration and poor quality of the majority of trials, as well as significant unexplained between-study heterogeneity, there remains a need for larger, longer, high-quality trials.

Nuts in the prevention and treatment of metabolic syndrome.

Salas-Salvado´, J., M. Guasch-Ferre´, M. Bullo´, J. Sabate´, 2014. Nuts in the prevention and treatment of metabolic syndrome. Am J Clin Nutr. 100(suppl):399S–407S,

Nuts are rich in many bioactive compounds that can exert beneficial effects on cardiovascular health. We reviewed the evidence relating nut consumption and the metabolic syndrome (MetS) and its components. Nuts reduce the postprandial glycemic response; however, long-term trials of nuts on insulin resistance and glycemic control in diabetic individuals are inconsistent. Epidemiologic studies have shown that nuts may lower the risk of diabetes incidence in women. Few studies have assessed the association between nuts and abdominal obesity, although an inverse association with body mass index and general obesity has been observed. Limited evidence suggests that nuts have a protective effect on blood pressure and endothelial function. Nuts have a cholesterol-lowering effect, but the relation between nuts and hypertriglyceridemia and high-density lipoprotein cholesterol is not well established. A recent pooled analysis of clinical trials showed that nuts are inversely related to triglyceride concentrations only in subjects with hypertriglyceridemia. An inverse association was found between the frequency of nut consumption and the prevalence and the incidence of MetS. Several trials evaluated the effect of nuts on subjects with MetS and found that they may have benefits in some components. Compared with a low-fat diet, a Mediterranean diet enriched with nuts could be beneficial for MetS management. The protective effects on metabolism could be explained by themodulation of inflammation and oxidation. Further trials are needed to clarify the role of nuts in MetS prevention and treatment.