Archive

Research Nut: Cashews

The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials.

Tindall, A.M., E.A. Johnston, P.M. Kris-Etherton, K.S. Petersen, 2019. The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 109:297–314.

Background: Observational evidence suggests higher nut consumption is associated with better glycemic control; however, it is unclear if this association is causal. Objectives: We aimed to conduct a systematic review and meta-analysis of randomized controlled trials to examine the effect of tree nuts and peanuts on markers of glycemic control in adults. Methods: A systematic review and meta-analysis of randomized controlled trials was conducted. A total of 1063 potentially eligible articles were screened in duplicate. From these articles, 40 were eligible for inclusion and data from these articles were extracted in duplicate. The weighted mean difference (WMD) between the nut intervention and control arms was determined for fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR) using the DerSimonian and Laird random-effects method. For outcomes where a limited number of studies were published, a qualitative synthesis was presented. Results: A total of 40 randomized controlled trials including 2832 unique participants, with a median duration of 3 mo (range: 1–12 mo), were included. Overall consumption of tree nuts or peanuts had a favorable effect on HOMA-IR (WMD: −0.23; 95% CI: −0.40, −0.06; I2=51.7%) and fasting insulin (WMD: −0.40μIU/mL;95% CI: −0.73, −0.07μ IU/mL; I2 = 49.4%). There was no significant effect of nut consumption on fasting blood glucose (WMD: −0.52 mg/dL;95% CI: −1.43,0.38mg/dL; I2 =53.4%) o rHbA1c (WMD: 0.02%; 95% CI: −0.01%, 0.04%; I2 =51.0%). Conclusions: Consumption of peanuts or tree nuts significantly decreased HOMA-IR and fasting insulin; there was no effect of nut consumption on HbA1c or fasting glucose. The results suggest that nut consumption may improve insulin sensitivity. In the future, well-designed clinical trials are required to elucidate the mechanisms that account for these observed effects.

Metabolizable energy from cashew nuts is less than that predicted by Atwater factors.

Baer, D.J., J.A. Novotny, 2019. Metabolizable energy from cashew nuts is less than that predicted by Atwater factors. Nutrients. 11, 33; doi:10.3390/nu11010033.

Recent studies have demonstrated that the energy provided by several tree nuts is less than that predicted by the Atwater factors, though energy available from cashews has never been assessed. The objective of this study was to evaluate the metabolizable energy in cashew nuts. Eighteen healthy adults were enrolled in a randomized, crossover study with two treatment periods. Subjects were fed a fully controlled base diet for 4 weeks with either no additions or with the addition of 42 g/day (1.5 servings) of cashew nuts, with the final treatment diets being isocaloric. Complete diet collections were analyzed for nitrogen (for protein), fat, energy, and carbohydrate by difference. During the final week of each intervention phase, subjects collected all feces and urine produced, and these were also analyzed for nitrogen (feces and urine), energy (feces and urine), and fat (feces). The resulting data were used to calculate the metabolizable energy of cashews and the digestibility of macronutrients. The average available energy (calorie) content of a 28g serving of cashew nuts was137 kcal (±3.4kcal SEM) and ranged from 105 to 151 kcal. The mean value of 137 kcal/serving is 16% lower (p < 0.0001) than what is typically found on food labels. Digestibility of energy, fat, protein, and carbohydrate was lower for the cashew-containing diet compared to the control diet (92.9% vs. 94.9%, p < 0.0001 for energy; 96.1% vs. 97.8%, p = 0.0009 for fat; 90.1% vs. 91.2%, p = 0.0012 for protein; 92.9% vs. 94.9%, p < 0.0001 for carbohydrate; for the cashew-containing diet vs. the control diet, respectively). In conclusion, cashews provide fewer calories than the values predicted by the Atwater factors, as found on current food labels.

Nut and peanut butter consumption and the risk of lung cancer and its subtypes: A prospective cohort study.

Nieuwenhuis, I., P.A. van den Brandt, 2019. Nut and peanut butter consumption and the risk of lung cancer and its subtypes: A prospective cohort study. Lung Cancer. 128:57-66.
Objectives: Nut consumption has been associated with reduced cancer-related mortality, but evidence for a relation between nut intake and lung cancer risk is limited. We investigated the association between total nut, tree nut, peanut, and peanut butter intake and the risk of lung cancer and its subtypes in the Netherlands Cohort Study. Materials and Methods: In 1986, dietary and lifestyle habits of 120,852 participants, aged 55–69 years, were measured with a questionnaire. After 20.3 years of follow-up, 3720 subcohort members and 2861 lung cancer cases were included in multivariable case-cohort analyses. Results: Total nut intake was not significantly associated with total lung cancer risk in men or women. For small cell carcinoma, a significant inverse association with total nut intake was observed in men after controlling for detailed smoking habits (HR (95%CI) for 10+ g/day vs. non-consumers: 0.62 (0.43-0.89), p-trend: 0.024). Inverse relations with small cell carcinoma were also found for tree nut and peanut intake in men in continuous analyses (HR (95%CI) per 5g/day increment: 0.70 (0.53-0.93) and 0.93 (0.88-0.98), respectively). For the other lung cancer subtypes, no significant associations were seen in men. Nut intake was not related to the risk of lung cancer subtypes in women, and no associations were found for peanut butter in both sexes. Conclusion: Increased nut intake might contribute to the prevention of small cell carcinoma in men. No significant associations were found in men for the other subtypes or total lung cancer, in women, or for peanut butter intake.

Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: a randomized controlled trial.

Baer, D.J., J.A. Novotny, 2019. Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: a randomized controlled trial. Am J Clin Nutr 109:269–275.

Background: The US Food and Drug Administration (FDA) approved a qualified health claim for tree nuts and reduction of cardiovascular disease. However, cashews are excluded from that claim due to their content of saturated fats, which is predominantly stearic acid. Because stearic acid is neutral with respect to blood lipids, several studies have been conducted to test the effect of cashew nuts on blood lipids, and these studies have produced conflicting results. Objectives: The aim of this study was to conduct a highly controlled intervention to determine the effect of cashews fed at the amount specified in the health claim on risk factors for cardiovascular disease. Methods: A total of 42 adults participated in a controlled-feeding study conducted as a randomized crossover trial with 2 treatment phases. The volunteers were provided the same base diet in both treatment phases, with no additions during the control phase and with the addition of 1.5 servings (42 g) of cashews/d for the cashew nut phase. During the cashew nut phase, the amount of all foods was decreased proportionally to achieve isocaloric overall diets in the 2 phases. After 4 wk of intervention, assessments included blood lipids, blood pressure, central (aortic) pressure, augmentation index, blood glucose, endothelin, proprotein convertase subtilisin/kexin type 9 (PCSK9), adhesion molecules, and clotting and inflammatory factors. Results: There were no significant differences in blood lipids, blood pressure, augmentation index, blood glucose, endothelin, adhesion molecules, or clotting factors in this weight-stable cohort. PCSK9 was significantly decreased after cashew consumption, although there was no change in LDL cholesterol. Conclusions: Consumption of 1.5 servings of cashew nuts/d, the amount associated with the FDA qualified health claim for tree nuts and cardiovascular disease, did not positively or adversely affect any of the primary risk factors for cardiovascular disease. This trial was registered at clinicaltrials.gov as NCT02628171

Nut Consumption and Survival in Patients With Stage III Colon Cancer: Results From CALGB 89803 (Alliance).

Fadelu, T., S. Zhang, D. Niedzwiecki, X. Ye, L.B. Saltz, R.J. Mayer, R.B. Mowat, R. Whittom, A. Hantel, A.B. Benson, D.M. Atienza, M. Messino, H.L. Kindler, A. Venook, S. Ogino, K. Ng, K. Wu, W. Willett, E. Giovannucci, J. Meyerhardt, Y. Bao, C.S. Fuchs, 2018. Nut Consumption and Survival in Patients With Stage III Colon Cancer: Results From CALGB 89803 (Alliance). J Clin Oncol. 36(11):1112-1120.

Purpose: Observational studies have reported increased colon cancer recurrence and mortality in patients with states of hyperinsulinemia, including type 2 diabetes, obesity, sedentary lifestyle, and high glycemic load diet. Nut intake has been associated with a lower risk of type 2 diabetes, metabolic syndrome, and insulin resistance. However, the effect of nut intake on colon cancer recurrence and survival is not known. Patients and Methods: We conducted a prospective, observational study of 826 eligible patients with stage III colon cancer who reported dietary intake on food frequency questionnaires while enrolled onto a randomized adjuvant chemotherapy trial. Using Cox proportional hazards regression, we assessed associations of nut intake with cancer recurrence and mortality. Results: After a median follow-up of 6.5 years, compared with patients who abstained from nuts, individuals who consumed two or more servings of nuts per week experienced an adjusted hazard ratio (HR) for disease-free survival of 0.58 (95% CI, 0.37 to 0.92; Ptrend = .03) and an HR for overall survival of 0.43 (95% CI, 0.25 to 0.74; Ptrend = .01). In subgroup analysis, the apparent benefit was confined to tree nut intake (HR for disease-free survival, 0.54; 95% CI, 0.34 to 0.85; Ptrend = .04; and HR for overall survival, 0.47; 95% CI, 0.27 to 0.82; Ptrend = .04). The association of total nut intake with improved outcomes was maintained across other known or suspected risk factors for cancer recurrence and mortality. Conclusion: Diets with a higher consumption of nuts may be associated with a significantly reduced incidence of cancer recurrence and death in patients with stage III colon cancer.

Effect of nut consumption on semen quality and functionality in healthy men consuming a Western-style diet: a randomized controlled trial.

Salas-Huetos, A., R. Moraleda, S. Giardina, E. Anton, J. Blanco, J. Salas-Salvadó, M. Bulló, 2018. Effect of nut consumption on semen quality and functionality in healthy men consuming a Western-style diet: a randomized controlled trial. Am J Clin Nutr. 108:953–962.

Background: Human semen quality has declined in industrialized countries. Pollution, smoking, and the consumption of a Western style diet are all hypothesized as potential causes. Objective: We evaluated the effect of chronic consumption of nuts on changes in conventional semen parameters and the potential mechanisms implicated. Design: The FERTINUTS study was a 14-wk randomized, controlled, parallel trial. A total of 119 healthy men, aged 18–35 y, were allocated to 1 of 2 intervention groups: one group was fed the usual Western-style diet enriched with 60 g of a mixture of nuts/d (nut group), and the other was fed the usual Western-style diet avoiding nuts (control group). Semen and blood samples were collected at baseline and at the end of the intervention. Dietary information was recorded throughout the trial. Changes in conventional semen parameters (pH, volume, sperm count and concentration, motility, and morphology) were determined as primary outcomes. The effect of nut consumption on sperm DNA fragmentation (SDF), reactive oxygen species (ROS) production, chromosome anomalies (X, Y, and 18), total DNA methylation, and microRNA expression were measured in sperm samples as potential causes of the changes in the seminogram. Results: Compared with the control group, improvements in total sperm count (P = 0.002) and vitality (P = 0.003), total motility (P = 0.006), progressive motility (P = 0.036), and morphology of sperm (P = 0.008) were observed in the nut group. Participants in the nut group showed an increase in the consumption of total fat, monounsaturated fatty acids, polyunsaturated fatty acids, magnesium, vitamin E, α-linolenic acid, total omega-3 (n–3) and ω-3: ω-6 ratio intake during the intervention. Participants in the nut group showed a significant reduction in SDF (P < 0.001) and in the expression of hsa-miR-34b-3p (P = 0.036). No significant changes in ROS, sperm chromosome anomalies, or DNA methylation were observed between groups. Conclusions: The inclusion of nuts in a Western-style diet significantly improves the total sperm count and the vitality, motility, and morphology of the sperm. These findings could be partly explained by a reduction in the sperm DNA fragmentation. This trial was registered at ISRCTN as ISRCTN12857940.

Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials.

Xiao, Y., W. Huang, C. Peng, J. Zhang, C. Wong, J.H. Kim, E.-K. Yeoh, 2017. Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials. Clinical Nutrition. http://dx.doi.org/10.1016/j.clnu.2017.04.011

Objective: Nut consumption has consistently been found to be associated with a reduced risk of cardiovascular diseases (CVD) and mortality in prospective studies. However, its effect on endothelial function, a prognostic marker of CVD, is still controversial in clinical trials. This meta-analysis of randomized controlled trials (RCTs) aimed to quantitatively assess the effect of nuts on vascular endothelial function. Methods: Major electronic databases were searched for published RCTs that reported the effect of nuts on flow mediated dilation (FMD) as a measurement of endothelial function in the adult population (age eighteen years or over). We calculated the pooled estimates of weighted mean differences (WMDs) and their 95% confidence intervals (CIs) by using random-effects models. Results: A total of nine papers (10 trials) involving 374 participants were included. The pooled estimates found that nut consumption significantly improved FMD (WMD: 0.41%; 95% CI: 0.18%, 0.63%; P = 0.001). Moderate and marginally significant heterogeneity was observed among the studies (I2 = 39.5%, P = 0.094). Subgroup analyses indicated that walnuts significantly improved FMD (WMD: 0.39%; 95% CI: 0.16%, 0.63%; P = 0.001). In addition, nut consumption had a significant effect on FMD in the trials with study duration <18 weeks, nut dose <67 g/d, or subjects with baseline FMD ≥8.6%. Conclusions: Nut consumption significantly improved endothelial function. However, the beneficial effect was limited to walnuts. More studies examining the effect of other nuts on endothelial function are needed in the future.

Replacing American snacks with tree nuts increases consumption of key nutrients among US children and adults: results of an NHANES modeling study.

Rehm, C.D., A. Drewnowski. 2017. Replacing American snacks with tree nuts increases consumption of key nutrients among US children and adults: results of an NHANES modeling study. Nutr. J. doi:10.1186/s12937017-0238-5.

Background: Replacing typical American snacks with tree nuts may be an effective way to improve diet quality and compliance with the 2015–2020 Dietary Guidelines for Americans (DGAs). Objective: To assess and quantify the impact of replacing typical snacks with composite tree nuts or almonds on diet metrics, including empty calories (i.e., added sugars and solid fats), individual fatty acids, macronutrients, nutrients of public health concern, including sodium, fiber and potassium, and summary measures of diet quality. Methods: Food pattern modeling was implemented in the nationally representative 2009–2012 National Health and Examination Survey (NHANES) in a population of 17,444 children and adults. All between-meal snacks, excluding beverages, were replaced on a per calorie basis with a weighted tree nut composite, reflecting consumption patterns in the population. Model 1 replaced all snacks with tree nuts, while Model 2 exempted whole fruits, non-starchy vegetables, and whole grains (>50% of total grain content). Additional analyses were conducted using almonds only. Outcomes of interest were empty calories (i.e., solid fats and added sugars), saturated and mono- and polyunsaturated fatty acids, fiber, protein, sodium, potassium and magnesium. The Healthy Eating Index-2010, which measures adherence to the 2010 Dietary Guidelines for Americans, was used as a summary measure of diet quality. Results: Compared to observed diets, modeled food patterns were significantly lower in empty calories (−20.1% and −18.7% in Model 1 and Model 2, respectively), added sugars (−17.8% and −16.9%), solid fats (−21.0% and −19.3%), saturated fat (−6.6% and −7.1%)., and sodium (−12.3% and −11.2%). Modeled patterns were higher in oils (65.3% and 55.2%), monounsaturated (35.4% and 26.9%) and polyunsaturated fats (42.0% and 35.7%), plant omega 3 s (53.1% and 44.7%), dietary fiber (11.1% and 14.8%), and magnesium (29.9% and 27.0%), and were modestly higher in potassium (1.5% and 2.9%). HEI-2010 scores were significantly higher in Model 1 (67.8) and in Model 2 (69.7) compared to observed diets (58.5). Replacing snacks with almonds only produced similar results; the decrease in sodium was more modest and no increase in plant omega-3 fats was observed. Conclusion: Replacing between-meal snacks with tree nuts or almonds led to more nutrient-rich diets that were lower in empty calories and sodium and had more favorable fatty acid profiles. Food pattern modeling using NHANES data can be used to assess the likely nutritional impact of dietary guidance.

 

Determination of myo-inositol phosphates in tree nuts and grain fractions by HPLC–ESI–MS.

Duong, Q.H., K.D. Clark, K.G. Lapsley, R.B. Pegg. 2017. Determination of myo-inositol phosphates in tree nuts and grain fractions by HPLC–ESI–MS. J. Food Comp. Anal. 59:74-82.

High-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC–ESI–MS) was utilized for the rapid, on-line detection of all six forms of inositol phosphate (InsP) in seven major tree nuts (i.e., cashews, Brazil nuts, macadamias, walnuts, pecans, pistachios, hazelnuts) and three grain components that are allegedly rich in phosphorus (wheat aleurone, rice bran, corn germ). The total InsP levels ranged from 3 to 20 μmol/g in the tree nuts and from 10 to 97 μmol/g in the grain components. While inositol hexakisphosphate was the predominant form in all samples, at least 20% of the InsP molar concentration comprised lower forms of InsPs. In tree nuts, InsPs accounted for 18–59% of the organic phosphorus content and 12–46% of the total phosphorus content. For grain samples, these values ranged from 66–97% and 58–80%, respectively. Significant differences in InsP levels among tree nuts underline the need for further investigation of InsPs in this food group, particularly with regard to different cultivars, growing conditions, and processing conditions. HPLC–ESI–MS offered a sensitive and time-efficient detection approach for InsPs in various complex nut and grain matrices, highlighting its potential application for many other sample types.

 

An umbrella review of nuts intake and risk of cardiovascular disease.

Schwingshackl, L., G. Hoffmann, B. Missbach, M. Stelmach-Mardas, H. Boeing, 2017. An umbrella review of nuts intake and risk of cardiovascular disease. Current Pharmaceutical Design. 23:1016-1027.

Background: Nuts have been an indispensable component of the human diet for hundreds because of their unique nutrient composition and are thought to play a beneficial part in the prevention of cardiovascular diseases. Objective: To evaluate the extent, validity and presence of evidence for studies investigating the impact of nuts intake on biomarkers of cardiovascular disease and cardiovascular events, we performed an umbrella review of all published meta-analyses synthesizing data from both observational studies and randomized controlled trials. Method: PubMed (between 1966 and April 2016) was searched for systematic reviews and meta-analyses. Methodological quality was assessed by applying the AMSTAR score (0-11 points), and the meta-evidence by applying NutriGrade, our recently developed scoring system (0-10 points). Results: In total, 14 meta-analyses were included in the umbrella review. Only 4 out of 14 reported an AMSTAR score ≥8 (high methodological quality), whereas NutriGrade meta-evidence score varied between 2 (very low meta-evidence) and 7.9 (moderate meta-evidence). There is consistent evidence from intervention trials, reporting significant reductions for total cholesterol, and from observational studies that higher intakes of nuts were associated with reduced risk of cardiovascular disease and hypertension. On the other side no effect could be observed for stroke, HDL-cholesterol, and blood pressure in the normal range.  Conclusion: In summary, the present umbrella review showed that nuts intake was associated with reduced risk of cardiovascular disease and hypertension, and lower levels of total cholesterol. The observed evidence is limited by the moderate methodological quality and very low to moderate quality of evidence.