Walnut Intake Research Articles

A case of anaphylaxis caused by exposure to walnuts

Anaphylaxis is an acute serious systemic allergic reaction that can lead to death, requiring immediate diagnosis and treatment. In particular, food is the most common cause in children, adolescents, and young adults. In addition to physical contact between food and skin, anaphylaxis can also be induced by exposure other than ingestion, such as inhalation of aerosolized food proteins. Korean males undergo medical screening prior to a compulsory military service. A history of possible food allergy requires referral to a spe-cialized allergy clinic. A 19-year-old male patient enlisted in the military was referred to the allergy clinic for an oral provocation test. It was confirmed that anaphylaxis was caused not only by walnut intake, but also by skin contact or by inhaling walnut particles. We report the case with the literature review. (Allergy Asthma Respir Dis 2021;9:245-248)

Identifying Usual Food Choice Combinations With Walnuts: Analysis of a 2005-2015 Clinical Trial Cohort of Overweight and Obese Adults.

Consumption of nuts has been associated with a range of favorable health outcomes. Evidence is now emerging to suggest that walnuts may also play an important role in supporting the consumption of a healthy dietary pattern. However, limited studies have explored how walnuts are eaten at different meal occasions. The aim of this study was to explore the food choices in relation to walnuts at meal occasions as reported by a sample of overweight and obese adult participants of weight loss clinical trials. Baseline usual food intake data were retrospectively pooled from four food-based clinical trials (n = 758). A nut-specific food composition database was applied to determine walnut consumption within the food intake data. The a priori algorithm of association rules was used to identify food choices associated with walnuts at different meal occasions using a nested hierarchical food group classification system. The proportion of participants who were consuming walnuts was 14.5% (n = 110). The median walnut intake was 5.14 (interquartile range, 1.10–11.45) g/d. A total of 128 food items containing walnuts were identified for walnut consumers. The proportion of participants who reported consuming unsalted raw walnut was 80.5% (n = 103). There were no identified patterns to food choices in relation to walnut at the breakfast, lunch, or dinner meal occasions. A total of 24 clusters of food choices related to walnuts were identified at others (meals). By applying a novel food composition database, the present study was able to map the precise combinations of foods associated with walnuts intakes at mealtimes using data mining. This study offers insights into the role of walnuts for the food choices of overweight adults and may support guidance and dietary behavior change strategies.

Investigating walnut consumption and cognitive trajectories in a representative sample of older US adults.

Existing research suggests walnut intake may be associated with better cognitive function in older adults, yet few studies utilise longitudinal data from observational studies of ageing populations. Our objective was to estimate the association between whole walnut intake and cognitive change in a representative sample of older Americans. Secondary analysis of the Health and Retirement Study and Health Care and Nutrition Study. Walnut consumption was defined as a categorical measure (none, low intake (0·01-0·08 1 oz. servings per day) and moderate intake (>0·08 1 oz. servings per day)) and cognitive function was measured using the Telephone Interview for Cognitive Status. Latent growth modelling estimated the association between walnut consumption and trajectories of cognitive status over a 4-year observational period. Sensitivity analyses assessing non-random dropout and Monte Carlo power analyses were conducted to contextualise results. The USA. A sample of 3632 US adults aged 65 years and older. Those reporting any walnut consumption had greater cognitive scores at baseline than those not consuming walnuts (low walnut consumption, b = 1·53, se = 0·21, P < 0·001; moderate walnut consumption, b = 2·22, se = 0·27, P < 0·001), but walnut consumption was not associated with cognitive change. Walnut consumption was positively associated with socioeconomic status and health behaviours as well as intake of nutrients identified to have neuroprotective benefits. We identified an association between walnut consumption and cognitive function in older adults, although we did not find that walnut consumption was protective against age-related cognitive decline.

Effects of walnut intake on blood pressure: A systematic review and meta-analysis of randomized controlled trials.

The impact of walnuts on blood pressure (BP) is not a well-established fact. Although several studies have assessed the effects of walnut consumption on BP, results are conflicting. Thus, we examined the effects of walnut doses and length of supplementation on BP. Biomedical databases were searched for published trials that compared walnut-enhanced diet to control diet. Eighteen trials met eligibility criteria (n = 1,799). Overall, walnut consumption neither did alter SBP (weighted mean difference [WMD]: 0.08 mmHg; 95% CI: -0.69, 0.85) nor DBP (WMD: 0.08 CI: -0.26, 0.42). In subgroup analyses, walnut ingestion ≤40 g was statistically correlated with reduction in SBP (WMD: -0.53 mmHg, 95% CI: -0.79, -0.26) and DBP (WMD: -0.191 mmHg, 95% CI: -0.384, -0.034). Moreover, the length of intervention ≥8 weeks was linked to a significant reduction in SBP (WMD: -1.18 mmHg, 95% CI: -1.30, -1.06). Following dose-response evaluation, walnut intake significantly changed SBP (p = .015) and DBP (p = .026) through a nonlinear fashion at walnut dose up to 40 g/d. Nevertheless, these statistical results cannot be translated into clinical practice, once the changes expressed as WMD are slight taking into consideration the absolute values of BP categories. In conclusion, this meta-analysis does not support walnut consumption as a BP-lowering strategy.

Estimating Sample Size Required to Establish an Association Between Walnut Intake and Cognitive Change in Older Adults: An Application of Monte Carlo Power Analysis

Abstract Objectives Observational studies support a cross-sectional association between walnut intake and cognitive function among older adults, but few of these studies identify walnut intake as a predictor of cognitive change. This project estimates the sample size required to establish a statistically significant association between walnut intake and cognitive change in an observational study using Monte Carlo power analysis. Methods Initial observations were drawn from the 2012, 2014, and 2016 Health and Retirement Study (HRS) and the 2013 Health Care and Nutrition Study (HCNS; age ≥ 65, n = 3632). Global cognitive function was measured using the Telephone Interview for Cognitive Status and two operationalizations of walnut intake were investigated (none, low intake (.01 – .08 servings/day), and moderate intake (&amp;gt; .08 servings/day); no intake vs. any intake). Latent growth models adjusting for covariates and complex sample design were used to estimate age-based developmental trajectories of TICS scores as a function of walnut intake. Parameter estimates from these models were used as starting values in Monte Carlo simulation models replicated for sample sizes from 1000–50,000. Results Model estimation required around 1200 hours of processing time. When measured as a trichotomous variable, the observed association between walnut intake and cognitive change was weak (for moderate intake, b = −0.030, SE = .03) and would require at least 42,000 observations to reduce the standard error to a level where 80% or more of random samples would identify the effect as statistically significant (P &amp;lt; .05). When measured as a dichotomous variable, the observed effect was small (b = −0.013, SE = 0.025) and required a sample size of at least 39,000 observations to identify power above .80. Conclusions Given that the HRS and HCNS are nationally-representative studies, the population size from which an adequate sample would need to be drawn to identify walnut intake as a significant predictor of cognitive decline would exceed the number of adults age 65 and older currently living in the US. Rather than increase sample size of observational studies, researchers should apply quasi-experimental methods and detailed measurement of walnut intake to establish an association between walnut intake and cognitive change. Funding Sources This research was funded by the California Walnut Commission.

Association of Walnut Consumption with Total and Cause-Specific Mortality and Life Expectancy in U.S. Women and Men

Abstract Objectives We aim to 1) examine the association between walnut consumption and subsequent total and cause-specific mortality; 2) to estimate life expectancy that would be potentially gained by varying intake of walnuts in U.S. women and men. Methods Walnut consumption was assessed using validated food frequency questionnaires in 1998 (baseline year) and updated every 4 years. We included data from 68,308 women of the Nurses’ Health Study (1998–2016) and 26,760 men of the Health Professionals Follow-up Study (1998–2016) who were free of cancer, heart disease, and stroke at baseline. We used Cox regression models adjusting for confounders to estimate mortality risk associated with walnut consumption stratified by sex and dietary quality. We used population based multistate life tables to calculate the differences in life expectancy and years lived in relation to walnut consumption. Results During up to 18 years of follow-up, we documented 30,502 deaths from any cause. The multivariable-adjusted hazard ratios (HRs) for total mortality across categories of walnut intake (servings/week), as compared to non-consumers, were 0.91 (95% confidence interval [CI], 0.89–0.94), for &amp;lt;1 serving/week, 0.87 (95% CI, 0.83–0.92) for 1 serving/week, 0.79 (95% CI, 0.75–0.85), for 2–4 servings/week, and 0.77 (95% CI,: 0.71–0.81) for &amp;gt;= 5 servings/week (P for trend &amp;lt;0.0001). Per 0.5 serving/day walnut consumption was associated of a reduced risk of total mortality (HR: 0.82, 95% CI,: 0.77–0.88), CVD mortality (HR: 0.78, 95% CI,: 0.67–0.33), and cancer mortality (HR: 0.93, 95% CI:, 0.81–1.07) in participants with a suboptimal diet (AHEI score &amp;lt;60% of cohort distribution). A greater life expectancy of 1.78 years in women and 1.94 years in men was observed among those who consumed walnuts more than 5 servings/week, compared to non-consumers at age 60. Conclusions Higher walnut consumption was associated with lower risk for total mortality and longer estimated life expectancy among U.S. men and women of two prospective cohort studies. Our results provide evidence on the potential role of walnut in the prevention of premature death. Funding Sources UM1 CA186107, UM1 CA176726, UM1 CA167552 Y.L. was partly funded by the California Walnut Commission. The funders have no roles in the design and conduct of the study.

WALNUTS for POWER: A Protocol for the Polyphenols, Omega-3 Fatty Acids, Weight Loss, and EneRgy Randomized Controlled Trial

Abstract Objectives Prostate cancer (PC) is the most common non-skin cancer in men and the second leading cause of cancer death. Omega-3 fatty acids and polyphenols have bioactive properties that may alter tumor biology and reduce PC progression. Walnuts (Juglans regia L.) are one of the best sources of plant-based omega-3 s (2.5 g per oz) and polyphenols (total polyphenols 462 mg per oz). We propose to determine the effect of walnuts added to a typical diet on markers of PC progression in men scheduled for radical prostatectomy (RP). The primary objective of the study is to determine the effect of walnut intake on Ki67 expression in prostatic tissue. Secondary objectives are to determine the effect of walnuts on prostatic tissue oxidative stress and inflammation. Exploratory objectives include measuring the effect of walnuts on the gut microbiome, insulin/IGF signaling and gene expression. Methods 50 men with PC scheduled for RP are recruited from the Durham Veterans Medical Center and Cedars-Sinai Medical Center. Men are randomized to receive 2 oz. of walnuts added to a usual diet (intervention) or control (usual diet) using a 1:1 allocation during the 3–10-week pre-RP period. An experienced dietitian provides counseling and recipes to men in the intervention arm and monitor dietary compliance. RP tissue is stained and scored for Ki67 by an experienced pathologist. Tumors are processed for RNA extraction and RNA-sequenced at the UCLA genomics core. Fasting blood are collected at baseline and pre-RP visits, spun, separated into serum, plasma, and red blood cells and stored at −80°C. Serum are batch-analyzed for insulin, IGF-1, IGFBP-3, and IL-6. Stool samples for microbiota analyses are collected at baseline and pre-RP visits and undergo 16 s rRNA gene sequencing and statistical analyses to identify microbiome community content. Between-arm differences during the study are assessed by t-test for continuous variables and chi-square test for categorical variables. The study will be completed in 3 years. To date, 7 men have been recruited. Results N/A Conclusions If shown to be effective in improving PC outcomes in men diagnosed with early stage PC, this modest dietary change could provide a much needed feasible, low-cost, easily accessible, non-toxic option that could be sustained over the long-term. Funding Sources California Walnut Commission.

Effect of walnut consumption on markers of blood glucose control: a systematic review and meta-analysis.

Type 2 diabetes mellitus is a chronic disease increasing in global prevalence. Although habitual consumption of walnuts is associated with reduced risk of CVD, there is inconsistent evidence for the impact of walnut consumption on markers of glycaemic control. This systematic review and meta-analysis aimed to examine the effect of walnut consumption on markers of blood glucose control. A systematic search of Medline, PubMed, CINAHL and Cochrane databases (to 2 March 2019) was conducted. Inclusion criteria were randomised controlled trials conducted with adults which assessed the effect of walnut consumption on fasting blood glucose and insulin, glycated Hb and homeostatic model assessment of insulin resistance. Random effects meta-analyses were conducted to assess the weighted mean differences (WMD) for each outcome. Risk of bias in studies was assessed using the Cochrane Risk of Bias tool 2.0. Sixteen studies providing eighteen effect sizes were included in the review. Consumption of walnuts did not result in significant changes in fasting blood glucose levels (WMD: 0·331 mg/dl; 95 % CI -0·817, 1·479) or other outcome measures. Studies were determined to have either 'some concerns' or be at 'high risk' of bias. There was no evidence of an effect of walnut consumption on markers of blood glucose control. These findings suggest that the known favourable effects of walnut intake on CVD are not mediated via improvements in glycaemic control. Given the high risk of bias observed in the current evidence base, there is a need for further high-quality randomised controlled trials.

A Walnut-enriched Diet and Physical Activity Enhanced Cognitive and Motor Function in Aged Mice (P14-010-19)

ObjectivesThis study aims to investigate walnut’s effect alone and in combination with an enriched environment on brain aging of aged NMRI mice by investigation of cognition and motor functions. Furthermore, it aims to identify the underlying mechanisms by evaluating the expression of relevant genes. MethodsNMRI mice (12mo.) were fed with a 6% walnut-enriched diet (WED) or control diet respectively, for the duration of 6 months. Additionally, one WED group was exposed to an enriched environment. Cognition and motor functions were assessed to evaluate walnut’s effect on spatial memory, general physical activity and motor coordination. Conducted tests included Y-Maze alternation, open field and rotarod. Expression levels of relevant genes including synaptophysin, NGF and BDNF were measured via qPCR in brain tissue. Mitochondrial function was investigated by testing for ATP levels and mitochondrial membrane potential in dissociated brain cells and oxygen consumption of the oxidative phosphorylation system of freshly isolated mitochondria. ResultsIntake of the walnut diet significantly increased the alternation rate in a Y-Maze experiment (P < 0.05). Physical activity did not further improve this effect on spatial memory of mice, but increased mice’ activity (P < 0.001) in general. Motor function in rotarod test was not improved by walnut intake alone, but significantly increased by added enrichment (P < 0.01). Gene expression of synaptophysin was significantly increased for walnuts alone (P < 0.05), while BDNF and NGF expression appeared to be unaffected. Additional enriched environment resulted in a trend for these genes to be increased as well. Results imply that mitochondrial function is not linked to these improvements. ConclusionsLong term walnut diet significantly improved cognitive function in aged mice. Physical activity additionally improved motor functions. These benefits could possibly be explained by increased expression of genes involved in neuronal plasticity. Funding SourcesGrant from California Walnut Commission.

Influence of Walnut Intake on Vascular Function and Metabolism

Influence of Walnut Intake on Vascular Function and Metabolism

Daily walnut intake improves metabolic syndrome status and increases circulating adiponectin levels: randomized controlled crossover trial.

BACKGROUND/OBJECTIVESSeveral previous studies have investigated whether regular walnut consumption positively changes heart-health-related parameters. The aim of this study was to investigate the effects of daily walnut intake on metabolic syndrome (MetS) status and other metabolic parameters among subjects with MetS.SUBJECTS/METHODSThis study was a two-arm, randomized, controlled crossover study with 16 weeks of each intervention (45 g of walnuts or iso-caloric white bread) with a 6 week washout period between interventions. Korean adults with MetS (n = 119) were randomly assigned to one of two sequences; 84 subjects completed the trial. At each clinic visit (at 0, 16, 22, and 38 weeks), MetS components, metabolic parameters including lipid profile, hemoglobin A1c (HbA1c), adiponectin, leptin, and apolipoprotein B, as well as anthropometric and bioimpedance data were obtained.RESULTSDaily walnut consumption for 16 weeks improved MetS status, resulting in 28.6%-52.8% reversion rates for individual MetS components and 51.2% of participants with MetS at baseline reverted to a normal status after the walnut intervention. Significant improvements after walnut intake, compared to control intervention, in high-density lipoprotein cholesterol (HDL-C) (P = 0.028), fasting glucose (P = 0.013), HbA1c (P = 0.021), and adiponectin (P = 0.019) were observed after adjustment for gender, age, body mass index, and sequence using a linear mixed model.CONCLUSIONA dietary supplement of 45 g of walnuts for 16 weeks favorably changed MetS status by increasing the concentration of HDL-C and decreasing fasting glucose level. Furthermore, consuming walnuts on a daily basis changed HbA1c and circulating adiponectin levels among the subjects with MetS. This trial is registered at ClinicalTrials.gov as NCT03267901.

Effect of Adding Walnut Powder on Physical and Chemical Properties of Wheat Flour and Preventing Hyperlipidemia in Mice

Walnuts (Juglans regia L.) are naturally rich source of many important nutrients which could be helpful in different food processing. Walnut mainly containing polyunsaturated fatty acids (PUFA), especially alpha linoleic acid (18:3n-3; 9 g) and linoleic acid (18:3n-; 38 g). Walnuts powder was fortified with commercial high gluten wheat flour (WF) into 4 composites flour from 10% to 40%. Walnut flour improves the nutritional value due to high protein and fat content, but affects the technological properties. Parameters such as functional, pasting and rheological properties demonstrated the influence of walnut reincorporation into gluten network. The interaction of walnut flour with wheat flour is a key factor which effects on the dough quality, causing thinning and weakening the gluten structure. Flour with 30% to 40% walnut substitution was more nutritious especially in relation to protein and monounsaturated fatty acid (MUFA), but responsible for more changes in technological characteristics of dough. Present study was also directed to examine the effect of moderate walnut consumption on lipids profile, enzymatic anti-oxidant (superoxide dismutase SOD and glutathione peroxidase GSH-Px) and lipid peroxidation (Melondialdehyde MDA) in rats fed with high-fat food. The Sprague Dawley rats were housed for five weeks and assembled into normal, high fat, high fat (HF) + 10% walnut, HF + 20% walnut, HF + 30% walnut and HF + 40% walnut. The lipid profile significantly improved especially by lowering the low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) level increased in the group of HF + 40% walnut. The total anti-oxidant, SOD and GSH-Px activity were increased by supplementation of walnut and significantly higher in HF + 40% compared to the normal group. The Melondialdehyde (MDA) or lipid peroxidation status was increased in HF + 20% walnut to HF + 30% walnut as compared to normal and HF-fed diet but reduced by HF + 40% walnut. These results suggest that walnut intake could be effective to protect from oxidative stress by lowering the lipid peroxidation by improving antioxidant defense system in rats fed high-fat diet.

Association between walnut consumption and diabetes risk in NHANES.

BackgroundDietary interventions and cohort studies relating tree nut consumption to blood glucose levels suggest a possible effect of walnuts.ObjectiveTo examine the associations between walnut consumption and diabetes risk using data from the National Health and Nutrition Examination Survey.MethodsNational Health and Nutrition Examination Survey data on adults conducting 24‐hour dietary recall was pooled across the years 1999 through 2014. Diabetes status or risk was based on self‐report, medication use, fasting plasma glucose levels, and haemoglobin A1c (HbA1c) levels. Individuals were characterized based on reported consumption of walnuts, mixed‐nuts, or no nuts.ResultsAfter adjustment for covariates, walnut consumers showed lower risk for diabetes compared with non‐nut consumers based on self‐report (odds ratio of 0.47, 95% confidence interval [CI] 0.31‐0.72) as well as fasting blood glucose (relative risk ratio 0.32, CI 0.17‐0.58) and HbA1c (relative risk ratio 0.51, CI 0.27‐0.99). For each standard deviation of increase in walnut intake, prevalence of diabetes dropped 47%. The gender by walnut interaction suggests that the effect may be more potent among women than men (dose response P = .061).ConclusionsBoth among individuals with known diabetes and those diagnosed based on elevated diabetes blood markers, the prevalence of individuals with diabetes was significantly lower among the walnut consumers. A possible gender‐specific effect invites further attention.

Nut consumption and the risk of oesophageal squamous cell carcinoma in the Golestan Cohort Study

BackgroundNut consumption has been inversely associated with gastric cancer incidence in US-based studies, but not with oesophageal cancer. However, there is aetiologic heterogeneity, among oesophageal squamous cell carcinoma (ESCC) cases in low-risk vs. high-risk populations. The objective of this study was to evaluate the association between nut consumption and risk of ESCC in a high-risk population.MethodsThe Golestan Cohort Study enroled 50,045 participants in Northeastern Iran, between 2004 and 2008. Intake of peanuts, walnuts and mixed nuts (including seeds) were assessed using a validated food frequency questionnaire at baseline. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals for subsequent ESCC adjusted for potential confounders. Non-consumers of nuts were used as the reference category and the consumers were categorised into tertiles.ResultsWe accrued 280 incident ESCC cases during 337,983 person-years of follow up. Individuals in the highest tertiles of total nut consumption, and mixed nut consumption were significantly associated with lower risk of developing ESCC compared to non-consumers (HR = 0.60, 95% CI = 0.39–0.93, p-trend = 0.02, and HR = 0.52, 95% CI = 0.32–0.84, p trend = 0.002, respectively).ConclusionsWe found a statistically significant inverse association between total nut consumption and the risk of ESCC in this high-risk population.

A Walnut-Enriched Diet Reduces Lipids in Healthy Caucasian Subjects, Independent of Recommended Macronutrient Replacement and Time Point of Consumption: a Prospective, Randomized, Controlled Trial.

Studies indicate a positive association between walnut intake and improvements in plasma lipids. We evaluated the effect of an isocaloric replacement of macronutrients with walnuts and the time point of consumption on plasma lipids. We included 194 healthy subjects (134 females, age 63 ± 7 years, BMI 25.1 ± 4.0 kg/m2) in a randomized, controlled, prospective, cross-over study. Following a nut-free run-in period, subjects were randomized to two diet phases (8 weeks each). Ninety-six subjects first followed a walnut-enriched diet (43 g walnuts/day) and then switched to a nut-free diet. Ninety-eight subjects followed the diets in reverse order. Subjects were also randomized to either reduce carbohydrates (n = 62), fat (n = 65), or both (n = 67) during the walnut diet, and instructed to consume walnuts either as a meal or as a snack. The walnut diet resulted in a significant reduction in fasting cholesterol (walnut vs. control: −8.5 ± 37.2 vs. −1.1 ± 35.4 mg/dL; p = 0.002), non-HDL cholesterol (−10.3 ± 35.5 vs. −1.4 ± 33.1 mg/dL; p ≤ 0.001), LDL-cholesterol (−7.4 ± 32.4 vs. −1.7 ± 29.7 mg/dL; p = 0.029), triglycerides (−5.0 ± 47.5 vs. 3.7 ± 48.5 mg/dL; p = 0.015) and apoB (−6.7 ± 22.4 vs. −0.5 ± 37.7 mg/dL; p ≤ 0.001), while HDL-cholesterol and lipoprotein (a) did not change significantly. Neither macronutrient replacement nor time point of consumption significantly affected the effect of walnuts on lipids. Thus, 43 g walnuts/day improved the lipid profile independent of the recommended macronutrient replacement and the time point of consumption.

Daily walnut consumption effects lipid profile and body protein in Korean subjects with metabolic syndrome

The objective of current study was to assess the gender differences on the lipid profiles, apoprotein B, and body composition among the subjects with metabolic syndrome after daily walnut intake (45 g) for 16 weeks. 89 participants (44 men, 40±6.2yr) with metabolic syndrome were screened if they meet at least three metabolic syndrome components out of five diagnosis criteria (i.e., waist circumstance ≥90cm for men and ≥85cm for women, blood pressure 130/85mmHg or higher, HDL‐cholesterol ≤40mg/dL for men and ≤50mg/dL for women, triglyceride level ≥150mg/dL, and fasting blood glucose ≥100mg/dL). Blood lipid profiles (consisting of triglyceride, total cholesterol, HDL‐cholesterol, and LDL‐cholesterol), apoprotein B, fasting blood sugar, anthropometric measurement, bioimpedance analysis, and blood pressure were measured at baseline and week 16. The significance of the differences between baseline and week 16 were analyzed using the paired t‐test or Wilcoxon signed‐rank test, as appropriate (p&lt;0.05). Body protein of male and all subjects at week 16 was significantly higher compared to the baseline (p=0.026, p=0.039, respectively), whereas no significance among female subjects (p=0.876). Male showed significantly increased basal metabolic rate at week 16 (p=0.017), but not significant among female subjects (p=0.581) and all subjects (p=0.12). Waist circumstance among female and all subjects were significantly lower compared to baseline (p=0.036 and 0.026, respectively), and marginally significant among male subjects (p=0.050). LDL‐cholesterol and total cholesterol levels were significantly decreased among male subjects (p=0.011 and 0.003, respectively), whereas those among female subjects were not significantly different (p=0.307, and 0.072, respectively). Triglyceride level was significantly decreased among female subjects compared with baseline (p=0.007) by Wilcoxon test. The positive change of apoprotein B among male and all subjects were significant compared with the baseline (p=0.001 and 0.003, respectively), whereas those among female subjects were not significant (p=0.282). The results suggest that daily walnut consumption for 16 weeks may increase body protein and basal metabolic rate, and decrease the levels of LDL‐cholesterol, cholesterol and apoprotein B among male subjects with metabolic syndrome. Also, daily walnut intake may decrease waist circumstance and triglyceride level among female subjects with metabolic syndrome.IRB(SMWU‐1508‐BR‐051‐01)Support or Funding InformationCalifornia Walnut Commission

Consumption of Walnuts in Combination with Other Whole Foods Produces Physiologic, Metabolic, and Gene Expression Changes in Obese C57BL/6J High-Fat–Fed Male Mice

Background: Although a reductionist approach has sought to understand the roles of individual nutrients and biochemicals in foods, it has become apparent that there can be differences when studying food components in isolation or within the natural matrix of a whole food.Objective: The objective of this study was to determine the ability of whole-food intake to modulate the development of obesity and other metabolic dysfunction in mice fed a high-fat (HF), Western-style obesogenic diet. To test the hypothesis that an n–3 (ω-3) polyunsaturated fatty acid-rich food could synergize with other, largely polyphenol-rich foods by producing greater reductions in metabolic disease conditions, the intake of English walnuts was evaluated in combination with 9 other whole foods.Methods: Eight-week-old male C57Bl/6J mice were fed low-fat (LF; 10% fat) and HF control diets, along with an HF diet with 8.6% (wt:wt) added walnuts for 9 wk. The HF control diet contained 46% fat with added sucrose (10.9%, wt:wt) and cholesterol (1%, wt:wt); the added sucrose and cholesterol were not present in the LF diet. Other groups were provided the walnut diet with a second whole food—raspberries, apples, cranberries, tart cherries, broccoli sprouts, olive oil, soy protein, or green tea. All of the energy-containing whole foods were added at an energy level equivalent to 1.5 servings/d. Body weights, food intake, and glucose tolerance were determined. Postmortem, serum lipids and inflammatory markers, hepatic fat, gene expression, and the relative concentrations of 594 biochemicals were measured.Results: The addition of walnuts with either raspberries, apples, or green tea reduced glucose area under the curve compared with the HF diet alone (−93%, −64%, and −54%, respectively, P < 0.05). Compared with HF-fed mice, mice fed walnuts with either broccoli sprouts or green tea (−49% and −61%, respectively, P < 0.05) had reduced hepatic fat concentrations. There were differences in global gene expression patterns related to whole-food content, with many examples of differences in LF- and HF-fed mice, HF- and walnut-fed mice, and mice fed walnuts and walnuts plus other foods. The mean ± SEM increase in relative hepatic concentrations of the n–3 fatty acids α-linolenic acid, eicosapentanoic acid, and docosapentanoic acid in all walnut-fed groups was 124% ± 13%, 159% ± 11%, and 114% ± 10%, respectively (P < 0.0001), compared with LF- and HF-fed mice not consuming walnuts.Conclusions: In obese male mice, walnut consumption with an HF Western-style diet caused changes in hepatic fat concentrations, gene expression patterns, and fatty acid concentrations. The addition of a second whole food in combination with walnuts produced other changes in metabolite concentrations and gene expression patterns and other physiologic markers. Importantly, these substantial changes occurred in mice fed typical amounts of intake, representing only 1.5 servings each food/d.

Effects of Walnut Consumption on Colon Carcinogenesis and Microbial Community Structure.

Walnuts are composed of a complex array of biologically active constituents with individual cancer-protective properties. Here, we assessed the potential benefit of whole walnut consumption in a mouse tumor bioassay using azoxymethane. In study 1, a modest reduction (1.3-fold) in tumor numbers was observed in mice fed a standard diet (AIN-76A) containing 9.4% walnuts (15% of total fat). In study 2, the effects of walnut supplementation was tested in the Total Western Diet (TWD). There was a significant reduction (2.3-fold; P < 0.02) in tumor numbers in male mice fed TWD containing 7% walnuts (10.5% of total fat). Higher concentrations of walnuts lacked inhibitory effects, particularly in female mice, indicating there may be optimal levels of dietary walnut intake for cancer prevention. Since components of the Mediterranean diet have been shown to affect the gut microbiome, the effects of walnuts were therefore tested in fecal samples using 16S rRNA gene sequencing. Carcinogen treatment reduced the diversity and richness of the gut microbiome, especially in male mice, which exhibited lower variability and greater sensitivity to environmental changes. Analysis of individual operational taxonomic units (OTU) identified specific groups of bacteria associated with carcinogen exposure, walnut consumption, and/or both variables. Correlation analysis also identified specific OTU clades that were strongly associated with the presence and number of tumors. Taken together, our results indicate that walnuts afford partial protection to the colon against a potent carcinogenic insult, and this may be due, in part, to walnut-induced changes to the gut microbiome. Cancer Prev Res; 9(8); 692-703. ©2016 AACR.

Dietary compliance of walnut or no walnut intake in a 1‐year randomized intervention trial among free‐living elderly in the Walnuts and Healthy Aging Study (WAHA)

BackgroundDietary compliance is difficult to measure in clinical trials with free‐living subjects. Measuring dietary compliance relies on self‐reported dietary intake and, when available, biological markers.ObjectiveIn the context of a large clinical trial, we assessed compliance of a prescribed dietary intervention for a year of daily ingestion of walnuts or abstaining from walnuts in free‐living elderly.DesignDietary compliance was measured within the context of the Walnuts and Healthy Aging Study (WAHA), a randomized clinical trial assessing the effect of daily ingestion of walnuts on age‐related health outcomes. A total of 365 free‐living healthy elderly subjects (237 women, 199 men), ages 63–79 years old, from one center at Loma Linda University were considered for this assessment. Within the context of their habitual lifestyle, the walnut group (120 participants) was prescribed to consume an allotted amount of walnuts based upon 15% of their energy intake (30–60 grams) and proscribed up to 2 servings/week (2 oz.) of other nuts. The control group (137 participants) was prescribed to consume their habitual diet without any walnuts and the same proscription of up to 2 servings/week (2 oz.) of other nuts. Compliance was measured using two methods of self‐reporting; responses on a 179‐item semi‐quantitative food frequency questionnaire, and approximately three unannounced 24‐hour dietary recalls given per subject, for a total of over 1,000 completed 24‐hour dietary recalls. A third measure of compliance was taken to evaluate changes in plasma α‐linolenic acid in red blood cells from baseline to one year.ResultsIn the completed 24‐hour dietary recalls, 99% of the walnut group self‐reported consumption of daily allotted walnuts and only 1% of the control group self‐reported any ingestion of walnuts. The food frequency questionnaire determined average intake of other nuts was 1.90 servings/week (53.9 grams or 1.90 oz.) for the control group and 1.85 servings/week (52.4 grams or 1.85 oz.) for the walnut group, respectively. Self‐reported walnut intake on the food frequency questionnaire demonstrated that 95% of participants in the walnut group ingested at least 1 oz. of walnuts per day, compared to 0.7% in the control group. Together, the two self‐reported measures of compliance had 95% degree of correspondence within and between the two groups. The self‐reported measures coincide with changes observed in plasma α‐linolenic acid from baseline to one year. At baseline, both groups had equivalent means for plasma α‐linolenic acid at 0.31 for the walnut group and 0.29 for the control group (P= 0.167), however by the end of the first year, the walnut group increased by 28%, while the control group simultaneously decreased by 17% (P&lt; 0.001).ConclusionIn this elderly population, there was a high degree of congruence with the two methods of self‐reporting. Change observed in plasma α‐linolenic acid from baseline to one year was consistent with these self‐reported measures. Thus, simple self‐reported measures of dietary intake could suffice in long‐term clinical trials of nut intake.Support or Funding InformationCalifornia Walnut Commission

Effects of Walnut Consumption on Endothelial Function in People with Type 2 Diabetes: a Randomized Pilot Trial

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.