Djoussé, L., B. Lu, M.J. Gaziano, 2016. Effects of walnut consumption on endothelial function in people with type 2 diabetes: a randomized pilot trial. Curr Nutr Rep. 5(1):1-8.
The aim of this study was to obtain preliminary data to test the hypothesis that (1) a 12-week intervention with 28 g/day of walnuts improves endothelial function in people with type 2 diabetes mellitus (DM) and (2) intake of walnuts improves plasma adipokines after 12 weeks of intervention. In this pilot randomized, single-blinded, controlled trial of 26 adult subjects with prevalent DM, each subject was randomized to a usual diet with 28 g of walnuts per day or usual diet without walnuts (control group). Reactive hyperemia index (RHI), a measure of endothelial function, was measured non-invasively at baseline and after 12 weeks using Endo-PAT2000. We used linear regression to examine the effects of the intervention on RHI. The mean age at baseline was 64.8 ± 11.6 years; 61.5 % of participants were female, and 15.4 % had coronary artery disease. The standard error of RHI was 0.19. The difference in change in RHI during the intervention between the two groups was −0.029 (95 % confidence interval (CI) −0.52, 0.46, p = 0.23). Walnut intervention led to a suggestive increase in adiponectin, albeit non-statistically significant (difference 0.50 μg/ml (95 % CI −0.10, 1.09), p = 0.65). We demonstrated the feasibility of the proposed randomized trial and obtained needed standard deviations to calculate the required sample size to test proposed hypotheses in an efficacy trial.
Yu, Z., V.S. Malik, N. Keum, F.B. Hu, E.L. Giovannucci, M.J. Stampfer, W.C. Willett, C.S. Fuchs, Y. Bao, 2016. Associations between nut consumption and inflammatory biomarkers. AJCN. First published ahead of print July 27, 2016 as doi: 10.3945/ajcn.116.134205.
Background: Increased nut consumption has been associated with reduced risk of cardiovascular disease and type 2 diabetes, as well as a healthy lipid profile. However, the associations between nut consumption and inflammatory biomarkers are unclear. Objective: We investigated habitual nut consumption in relation to inflammatory biomarkers in 2 large cohorts of US men and women. Design: We analyzed cross-sectional data from 5013 participants in the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS) who were free of diabetes. Nut intake, defined as intake of peanuts and other nuts, was estimated from food frequency questionnaires, and cumulative averages from 1986 and 1990 in the NHS and from 1990 and 1994 in the HPFS were used. Plasma biomarkers were collected in 1989–1990 in the NHS and 1993–1995 in the HPFS. Multivariate linear regression was used to assess the associations of nut consumption with fasting plasma C-reactive protein (CRP, n = 4941), interleukin 6 (IL-6, n = 2859), and tumor necrosis factor receptor 2 (TNFR2, n = 2905). Results: A greater intake of nuts was associated with lower amounts of a subset of inflammatory biomarkers, after adjusting for demographic, medical, dietary, and lifestyle variables. The relative concentrations (ratios) and 95% CIs comparing subjects with nut intake of $5 times/wk and those in the categories of never or almost never were as follows: CRP: 0.80 (0.69, 0.90), P-trend = 0.0003; and IL-6: 0.86 (0.77, 0.97), P-trend = 0.006. These associations remained significant after further adjustment for body mass index. No significant association was observed with TNFR2. Substituting 3 servings of nuts/wk for 3 servings of red meat, processed meat, eggs, or refined grains/wk was associated with significantly lower CRP (all P , 0.0001) and IL-6 (P ranges from 0.001 to 0.017). Conclusion: Frequent nut consumption was associated with a healthy profile of inflammatory biomarkers.
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.
Ros, E., 2015. Nuts and CVD. Br J Nutr. 113, S111–S120.
Nuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds, such as l-arginine, fibre, healthful minerals, vitamin E, phytosterols and polyphenols. By virtue of their unique composition, nuts are likely to beneficially affect cardiovascular health. Epidemiological studies have associated nut consumption with a reduced incidence of CHD in both sexes and of diabetes in women, but not in men. Feeding trials have clearly demonstrated that consumption of all kinds of nuts has a cholesterol-lowering effect, even in the context of healthy diets. There is increasing evidence that nut consumption has a beneficial effect on oxidative stress, inflammation and vascular reactivity. Blood pressure, visceral adiposity and the metabolic syndrome also appear to be positively influenced by nut consumption. Contrary to expectations, epidemiological studies and clinical trials suggest that regular nut consumption is not associated with undue weight gain. Recently, the PREvención con DIeta MEDiterránea randomised clinical trial of long-term nutrition intervention in subjects at high cardiovascular risk provided first-class evidence that regular nut consumption is associated with a 50% reduction in incident diabetes and, more importantly, a 30% reduction in CVD. Of note, incident stroke was reduced by nearly 50% in participants allocated to a Mediterranean diet enriched with a daily serving of mixed nuts (15 g walnuts, 7·5 g almonds and 7·5 g hazelnuts). Thus, it is clear that frequent nut consumption has a beneficial effect on CVD risk that is likely to be mediated by salutary effects on intermediate risk factors.
Njike, V.Y., R. Ayettey, P. Petraro, J.A. Treu, D.L. Katz, 2015. Walnut ingestion in adults at risk for diabetes: effects on body composition, diet quality, and cardiac risk measures. BMJ Open Diabetes Research and Care. doi:10.1136/bmjdrc-2015-000115.
Background: Despite their energy density, walnuts can be included in the diet without adverse effects on weight or body composition. The effect of habitual walnut intake on total calorie intake is not well studied. Effects on overall diet quality have not been reported. Methods: Randomized, controlled, modified Latin square parallel design study with 2 treatment arms. The 112 participants were randomly assigned to a diet with or without dietary counseling to adjust calorie intake. Within each treatment arm, participants were further randomized to 1 of the 2 possible sequence permutations to receive a walnut-included diet with 56 g (providing 366 kcal) of walnuts per day and a walnut-excluded diet. Participants were assessed for diet quality, body composition, and cardiac risk measures. Results: When compared with a walnut-excluded diet, a walnut-included diet for 6 months, with or without dietary counseling to adjust caloric intake, significantly improved diet quality as measured by the Healthy Eating Index 2010 (9.14±17.71 vs 0.40±15.13; p=0.02 and 7.02±15.89 vs -5.92±21.84; p=0.001, respectively). Endothelial function, total and low-density lipoprotein (LDL) cholesterol improved significantly from baseline in the walnut-included diet. Body mass index, percent body fat, visceral fat, fasting glucose, glycated hemoglobin, and blood pressure did not change significantly. CONCLUSION: The inclusion of walnuts in an ad libitum diet for 6 months, with or without dietary counseling to adjust calorie intake, significantly improved diet quality, endothelial function, total and LDL cholesterol, but had no effects on anthropometric measures, blood glucose level, and blood pressure.
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.
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.
Viguiliouk, E., C.W.C. Kendall, S.B. Mejia, A.I. Cozma, V. Ha, A. Mirrahimi, V.H. Jayalath, L.S.A. Augustin, L. Chiavaroli, L.A. Leiter, R.J. de Souza, D. J.A. Jenkins, J.L. Sievenpiper, 2014. Effect of tree nuts on glycemic control in diabetes: A systematic review and meta-analysis of randomized controlled dietary trials. PLOS ONE. DOI: 10.1371/journal.pone.0103376
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0103376
Background: Tree nut consumption has been associated with reduced diabetes risk, however, results from randomized trials on glycemic control have been inconsistent. Objective: To provide better evidence for diabetes guidelines development, we conducted a systematic review and meta-analysis of randomized controlled trials to assess the effects of tree nuts on markers of glycemic control in individuals with diabetes. Data Sources: MEDLINE, EMBASE, CINAHL, and Cochrane databases through 6 April 2014. Study Selection: Randomized controlled trials ≥3 weeks conducted in individuals with diabetes that compare the effect of diets emphasizing tree nuts to isocaloric diets without tree nuts on HbA1c, fasting glucose, fasting insulin, and HOMA-IR. Data Extraction and Synthesis: Two independent reviewer’s extracted relevant data and assessed study quality and risk of bias. Data were pooled by the generic inverse variance method and expressed as mean differences (MD) with 95% CI’s. Heterogeneity was assessed (Cochran Q-statistic) and quantified (I2). Results: Twelve trials (n = 450) were included. Diets emphasizing tree nuts at a median dose of 56 g/d significantly lowered HbA1c (MD = −0.07% [95% CI:−0.10, −0.03%]; P = 0.0003) and fasting glucose (MD = −0.15 mmol/L [95% CI: −0.27, −0.02 mmol/L]; P = 0.03) compared with control diets. No significant treatment effects were observed for fasting insulin and HOMA-IR, however the direction of effect favoured tree nuts. Limitations: Majority of trials were of short duration and poor quality. Conclusions: Pooled analyses show that tree nuts improve glycemic control in individuals with type 2 diabetes, supporting their inclusion in a healthy diet. Owing to the uncertainties in our analyses there is a need for longer, higher quality trials with a focus on using nuts to displace high-glycemic index carbohydrates.
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.
Nishi, S.K., C.W.C. Kendall, R.P. Bazinet, B. Bashyam, C.A. Ireland, L.S.A. Augustin, S. Blanco Mejia, J.L. Sievenpiper, D.J.A. Jenkins, 2014. Nut consumption, serum fatty acid profile and estimated coronary heart disease risk in type 2 diabetes. Nutrition, Metabolism & Cardiovascular Diseases. 24(8):845-852.
Background and aims: Nut consumption has been associated with decreased risk of coronary heart disease (CHD) and type 2 diabetes which has been largely attributed to their healthy fatty acid profile, yet this has not been ascertained. Therefore, we investigated the effect of nut consumption on serum fatty acid concentrations and how these relate to changes in markers of glycemic control and calculated CHD risk score in type 2 diabetes. Methods and results: 117 subjects with type 2 diabetes consumed one of three iso-energetic (mean 475 kcal/d) supplements for 12 weeks: 1. full-dose nuts (50e100 g/d); 2. half-dose nuts with half-dose muffins; and 3. full-dose muffins. In this secondary analysis, fatty acid concentrations in the phospholipid, triacylglycerol, free fatty acid, and cholesteryl ester fractions from fasting blood samples obtained at baseline and week 12 were analyzed using thin layer and gas chromatography. Full-dose nut supplementation significantly increased serum oleic acid (OA) and MUFAs compared to the control in the phospholipid fraction (OA: P = 0.036; MUFAs: P = 0.024). Inverse associations were found with changes in CHD risk versus changes in OA and MUFAs in the triacylglycerol (r = -0.256, P = 0.011; r = -0.228, P = 0.024, respectively) and phospholipid (r = -0.278, P = 0.006; r = -0.260, P = 0.010, respectively) fractions. In the cholesteryl ester fraction, change in MUFAs was inversely associated with markers of glycemic control (HbA1c: r = -0.250, P = 0.013; fasting blood glucose: r = -0.395, P < 0.0001). Conclusion: Nut consumption increased OA and MUFA content of the serum phospholipid fraction, which was inversely associated with CHD risk factors and 10-year CHD risk
