Pandareesh, M.D., V. Chauhan, A. Chauhan, 2018. Walnut supplementation in the diet reduces oxidative damage and improves antioxidant status in transgenic mouse model of Alzheimer’s disease. J Alzheimers Dis. 64(4):1295-1305.
Our previous study has shown beneficial effects of walnuts on memory and learning skills in transgenic mouse model of Alzheimer’s disease (AD-tg). To understand underlying mechanism, we studied here whether walnuts can reduce oxidative stress in AD. From 4 months of age, experimental AD-tg mice were fed diets containing 6% (T6) or 9% walnuts (T9) (equivalent to 1 or 1.5 oz, of walnuts per day in humans) for 5, 10, or 15 months. The control groups, i.e., AD-tg (T0) and wild-type (Wt) mice, were fed diets without walnuts. Free radicals, i.e., reactive oxygen species (ROS), lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed in these mice at different ages. AD-tg mice on control diet (T0) showed significant age-dependent increase in ROS levels, lipid peroxidation, and protein oxidation coupled with impaired activities of antioxidant enzymes [superoxide dismutase, catalase, and glutathione peroxidase] compared to Wt mice. Oxidative stress was significantly reduced in AD-tg mice on diets with walnuts (T6, T9), as evidenced by decreased levels of ROS, lipid peroxidation, and protein oxidation, as well as by enhanced activities of antioxidant enzymes compared to T0 mice. Long-term supplementation with walnuts for 10 or 15 months was more effective in reducing oxidative stress in AD-tg mice. Our findings indicate that walnuts can reduce oxidative stress, not only by scavenging free radicals, but also by protecting antioxidant status, thus leading to reduced oxidative damage to lipids and proteins in AD. Therefore, by reducing oxidative stress, a walnut-enriched diet may help reduce the risk or delay the onset and progression of AD.
Njike, V.Y., V.C. Costales, P. Petraro, A. Annam, N. Yarandi, D.L. Katz, 2018. The resulting variation in nutrient intake with the inclusion of walnuts in the diets of adults at risk for type 2 diabetes: A randomized, controlled, crossover trial. Am J Health Promot. Aug 1:890117118791120. doi: 10.1177/0890117118791120. [Epub ahead of print]
PURPOSE: We previously demonstrated that including walnuts in the diets of adults at risk for type 2 diabetes mellitus (T2DM) led to improved overall diet quality. This report examines the specific changes in their nutrient intake. DESIGN: This was a randomized, controlled, modified Latin square parallel design trial with 2 treatment arms. Participants were randomized to walnut intake with, or without, dietary advice to regulate caloric intake. Within each treatment arm, they were further randomized to one of 2 sequence permutations (walnut-included/walnut-excluded or walnut-excluded/walnut-included diet), with a 3-month washout between treatment phases. SETTING: Community hospital in Lower Naugatuck Valley in Connecticut. PARTICIPANTS: Cohort of 112 participants (31 men and 81 women) at risk for T2DM. INTERVENTION: Participants included 56 g (366 kcal) of walnuts in their daily diets for 6 months. MEASURES: Nutrient intake was assessed using web-based Automated Self-Administered 24-Hour Dietary Assessment. ANALYSIS: Data were analyzed using generalized linear models. RESULTS: Walnut inclusion led to increased intake of total fat, calcium, magnesium, thiamin, total saturated fatty acids, and monounsaturated and polyunsaturated fatty acids (379.0 ± 90.3 g vs -136.5 ± 92.7 g, P < .01; 230.7 ± 114.2 mg vs -95.2 ± 117.4 mg, P = .05; 111.0 ± 33.9 mg vs -32.3 ± 34.9 mg, P < .01; 0.28 ± 0.2 mg vs -0.47 ± 0.2 mg, P = .02; 8.6 ± 3.4 g vs -1.1 ± 3.5 g, P =.05; 6.3 ± 3.9 g vs -6.3 ± 4.0 g, P = .03; and 25.4 ± 4.0 vs -6.6 ± 4.2 g, P < .01, respectively). Vitamin C intake decreased (-65.3 ± 55.3 mg vs 98.9 ± 56.8 mg, P = .04). Protein intake increased from baseline with the inclusion of walnuts (20.0 ± 8.8 g, P < .05). Walnut inclusion led to an increase in total calories consumed when caloric intake is not regulated. CONCLUSION: Including walnuts in the diets of these adults led to increased dietary intake of some nutrients associated with lower risk of developing T2DM and other cardiometabolic risk factors.
Ndanuko, R.N., L.C. Tapsell, K.E. Charlton, E.P. Neale, M.J. Batterham, 2018. Effect of individualised dietary advice for weight loss supplemented with walnuts on blood pressure: the HealthTrack study. Eur J Clin Nutr. 72(6):894-903.
BACKGROUND/OBJECTIVES: In addition to weight-loss, healthy dietary patterns and lower sodium intakes can help reduce blood pressure (BP), but individualised dietary advice may be necessary to achieve these effects. This study aimed to examine the impact of individualised dietary advice on BP in the intensive phase of a weight-loss trial. SUBJECTS/METHODS: Secondary analysis of baseline and 3-month data from the HealthTrack randomised controlled trial (n = 211). Participants were randomly assigned to one of three dietary advice groups: general advice (control), individualised advice (intervention group, I), or intervention group supplemented with 30 g walnuts/day (IW). Resting BP and 24-h urine sodium and potassium were measured. Dietary intake was evaluated through diet history interviews. RESULTS: Unadjusted SBP reduced significantly in all groups (IW and I groups P < 0.001; control group P = 0.002) and DBP in IW and I groups (P < 0.001). Compared to controls, the reductions in BP were 3-4 mmHg greater in the I and IW groups, but this only reached significance for DBP in the I group (-3.3 mmHg; P = 0.041). After controlling for age, sex, medication, weight-loss, physical activity and smoking, only the IW group showed a significant association between SBP reduction and increased urinary potassium (β = -0.101, P = 0.044), decreased sodium:potassium ratio (β = 2.446, P = 0.037) and increased consumption of seed and nut products and dishes (β = -0.108, P = 0.034). CONCLUSIONS: Dietary patterns with distinctive foods and lower sodium:potassium ratios may enhance the effects of weight-loss on BP. The patterns were best achieved with individualised dietary advice and food supplements.
McArthur, B.M., R.D. Mattes, R.V. Considine, 2018. Mastication of nuts under realistic eating conditions: implications for energy balance. Nutrients. 10(6), 710; https://doi.org/10.3390/nu10060710.
The low digestibility and high satiety effects of nuts have been partly attributed to mastication. This work examines chewing forces and the bolus particle size of nuts (walnuts, almonds, pistachios) varying in physical properties under different conditions (with and without water, juice, sweetened yogurt and plain yogurt) along with satiety sensations and gut hormone concentrations following walnut consumption (whole or butter). In a randomized, cross-over design with 50 adults (25 males, 25 females; Body Mass Index (BMI) 24.7 _ 3.4 kg/m2; age: 18–52 years old (y/o), the chewing forces and particle size distribution of chewed nuts were measured under different chewing conditions. Appetite sensations were measured at regular intervals for 3 h after nut intake, and plasma samples were collected for the measurement of glucose, insulin and Glucagon-like peptide-1 (GLP-1). The three nuts displayed different particle sizes at swallowing though no differences in chewing forces were observed. Walnuts with yogurt yielded larger particle sizes than the other treatments. Particle size was not correlated with either food palatability or flavor. Fullness sensations were higher after whole nut than nut butter consumption though there were no significant changes in glucose, insulin, or GLP-1 concentrations under any condition. Changing the conditions at swallowing might influence the release of energy from nuts.
Lee, H.J., Y.M. Han, J.M. An, E.A. Kang, Y.J. Park, J.Y. Cha, K.B. Hahm, 2018. Role of omega-3 polyunsaturated fatty acids in preventing gastrointestinal cancers: current status and future perspectives. Expert Rev Anticancer Ther. 17:1-15.
Although inflammation is defensive and healing process that maintains organ homeostasis, unresolved inflammation can lead to diseases. Polyunsaturated fatty acids (PUFAs), especially n-6 PUFAs abundant in Western diet, are precursors of pro-inflammatory mediators, whereas n-3 PUFAs possess anti-inflammatory properties. Therefore, interest in the cancer-preventive effect of n-3 PUFAs is increasing. Areas covered: We have observed significant reductions of gastrointestinal tumorigenesis in the Fat-1 transgenic mouse as evidenced that the decrease in Helicobacter pylori-infected gastric tumorigenesis, colon, biliary, and pancreatic cancer was seen in Fat-1 mice producing n-3 PUFAs. However, despite many studies showing benefits, evidence-based medicine regarding molecular pathology, epidemiology, and clinical achievement of cancer prevention of n-3 PUFAs are still limited. Expert commentary: Primary deficiency of eicosapentaenoic acids and docosahexaenoic acids in Western diets can explain the risk of cancer development and the importance of n-3/n-6 PUFA ratio in reducing cancer risk. Alteration of cell membrane composition during carcinogenesis is particularly important, due to increased rate of lipid/cholesterol synthesis in cancerous tissues. Here, we discuss that direct incorporation of n-3 PUFAs in the cell membrane corrects abnormal cellular proliferation and decreases inflammation-associated carcinogenesis. This is exemplified by cancer-preventive effects of n-3 PUFAs as fat sources for gastrointestinal cancers.
Koh, S.J., Y.I. Choi, Y. Kim, Y.S. Kim, S.W. Choi, J.W. Kim, B.G. Kim, K.L. Lee, 2018. Walnut phenolic extract inhibits nuclear factor kappaB signaling in intestinal epithelial cells, and ameliorates experimental colitis and colitis-associated colon cancer in mice. Eur J Nutr. doi: 10.1007/s00394-018-1704-3.
PURPOSE: Walnuts (Juglans regia) are known to have anti-cancer and immunomodulatory effects. However, little information is available on the effects of walnut phenolic extract (WPE) on intestinal inflammation and colitis-associated colon cancer. METHODS: COLO205 cells were pretreated with WPE and then stimulated with tumor necrosis factor (TNF)-α. In the acute colitis model, wild type mice (C57BL/6) were administered 4% dextran sulfate sodium (DSS) for 5 days. In the chronic colitis model, interleukin (IL)-10-/- mice were administered with either the vehicle or WPE (20 mg/kg) by oral gavage daily for 2 weeks. In an inflammation-associated tumor model, wild type mice were administered a single intraperitoneal injection of azoxymethane followed by three cycles of 2% DSS for 5 days and 2 weeks of free water consumption. RESULTS: WPE significantly inhibited IL-8 and IL-1α expression in COLO205 cells. WPE attenuated both the TNF-α-induced IκB phosphorylation/degradation and NF-κB DNA binding activity. The administration of oral WPE significantly reduced the severity of colitis in both acute and chronic colitis models, including the IL-10-/- mice. In immunohistochemical staining, WPE attenuated NF-κB signaling in the colons of both colitis models. Finally, WPE also significantly reduced tumor development in a murine model of colitis-associated colon cancer (CAC). CONCLUSIONS: WPE ameliorates acute and chronic colitis and CAC in mice, suggesting that WPE may have potentials for the treatment of inflammatory bowel disease.
Jacobs, D.R. Jr., K.S. Petersen, K. Svendsen, E. Ros, C.B. Sloan, L.M. Steffen, L.C. Tapsell, P.M. Kris-Etherton, 2018. Considerations to facilitate a US study that replicates PREDIMED. Metabolism. pii: S0026-0495(18)30118-5. doi: 10.1016/j.metabol.2018.05.001. [Epub ahead of print]
The PREDIMED clinical trial provided strong evidence that a Mediterranean dietary pattern (MedDiet) could help prevent cardiovascular disease (CVD) events in high risk middle-aged/older people. This report considers the feasibility of replicating PREDIMED in the U.S., including recommendations for dietary and behavioral principles. A 14-point Mediterranean diet Adherence Score (MEDAS) guided the PREDIMED MedDiet recommendations. At baseline MEDAS points were ~8.5. During intervention this score increased to nearly 11 in MedDiet vs. 9 in control. In the MedDiet groups, only about 0.5 points of the net 2 point MEDAS increase was attributable to the gratis supplements of olive oil or nuts. An issue in a U.S. replication is the large difference in typical U.S. versus Spanish diet and lifestyle. A typical U.S. diet would achieve a MEDAS of 1-2. A replication is scientifically feasible with an assumption such as that the MedDiet reflects a continuum of specific food choices and meal patterns. As such, a 2 point change in MEDAS at any point on the continuum would be hypothesized to reduce incident CVD. A conservative approach would aim for a randomized 4 point MEDAS difference, e.g. 5-6 points vs. an average U.S. diet group that achieved only 1-2 points.
Holscher, H.D., H.M. Guetterman, K.S. Swanson, R. An,N.R. Matthan, A.H. Lichtenstein, J.A. Novotny, D.J. Baer, 2018. Walnut consumption alters the gastrointestinal microbiota, microbially derived secondary bile acids, and health markers in healthy adults: a randomized controlled trial. J Nutr. doi: 10.1093/jn/nxy004. [Epub ahead of print]
Background: Epidemiologic data suggest that diets rich in nuts have beneficial health effects, including reducing total and cause-specific mortality from cancer and heart disease. Although there is accumulating preclinical evidence that walnuts beneficially affect the gastrointestinal microbiota and gut and metabolic health, these relations have not been investigated in humans. Objective: We aimed to assess the impact of walnut consumption on the human gastrointestinal microbiota and metabolic markers of health. Methods: A controlled-feeding, randomized crossover study was undertaken in healthy men and women [n = 18; mean age = 53.1 y; body mass index (kg/m2): 28.8]. Study participants received isocaloric diets containing 0 or 42 g walnuts/d for two 3-wk periods, with a 1-wk washout between diet periods. Fecal and blood samples were collected at baseline and at the end of each period to assess secondary outcomes of the study, including effects of walnut consumption on fecal microbiota and bile acids and metabolic markers of health. Results:
Compared with after the control period, walnut consumption resulted in a 49-160% higher relative abundance of Faecalibacterium, Clostridium, Dialister, and Roseburia and 16-38% lower relative abundances of Ruminococcus, Dorea, Oscillospira, and Bifidobacterium (P < 0.05). Fecal secondary bile acids, deoxycholic acid and lithocholic acid, were 25% and 45% lower, respectively, after the walnut treatment compared with the control treatment (P < 0.05). Serum LDL cholesterol and the non-cholesterol sterol campesterol concentrations were 7% and 6% lower, respectively, after walnut consumption compared with after the control treatment (P < 0.01). Conclusions: Walnut consumption affected the composition and function of the human gastrointestinal microbiota, increasing the relative abundances of Firmicutes species in butyrate-producing Clostridium clusters XIVa and IV, including Faecalibacterium and Roseburia, and reducing microbially derived, proinflammatory secondary bile acids and LDL cholesterol. These results suggest that the gastrointestinal microbiota may contribute to the underlying mechanisms of the beneficial health effects of walnut consumption.
Guasch-Ferré, M., J. Li, F.B. Hu, J. Salas-Salvadó, D.K. Tobias, 2018. Effects of walnut consumption on blood lipids and other cardiovascular risk factors: an updated meta-analysis and systematic review of controlled trials. Am J Clin Nutr. doi: 10.1093/ajcn/nqy091. [Epub ahead of print]
BACKGROUND: Intervention studies suggest that incorporating walnuts into the diet may improve blood lipids without promoting weight gain. OBJECTIVE: We conducted a systematic review and meta-analysis of controlled trials evaluating the effects of walnut consumption on blood lipids and other cardiovascular risk factors. Design: We conducted a comprehensive search of PubMed and EMBASE databases (from database inception to January 2018) of clinical trials comparing walnut-enriched diets with control diets. We performed random-effects meta-analyses comparing walnut-enriched and control diets for changes in pre-post intervention in blood lipids (mmol/L), apolipoproteins (mg/dL), body weight (kg), and blood pressure (mm Hg). RESULTS: Twenty-six clinical trials with a total of 1059 participants were included. The following weighted mean differences (WMDs) in reductions were obtained for walnut-enriched diets compared with control groups: -6.99 mg/dL (95% CI: -9.39, -4.58 mg/dL; P < 0.001) (3.25% greater reduction) for total blood cholesterol (TC) and -5.51 mg/dL (95% CI: -7.72, -3.29 mg/dL; P < 0.001) (3.73% greater reduction) for low-density lipoprotein (LDL) cholesterol. Triglyceride concentrations were also reduced in walnut-enriched diets compared with control [WMD = -4.69 (95% CI: -8.93, -0.45); P = 0.03; 5.52% greater reduction]. More pronounced reductions in blood lipids were observed when walnut interventions were compared with American and Western diets [WMD for TC = -12.30 (95% CI: -23.17, -1.43) and for LDL = -8.28 (95% CI: -13.04, -3.51); P < 0.001]. Apolipoprotein B (mg/dL) was also reduced significantly more on walnut-enriched diets compared with control groups [WMD = -3.74 (95% CI: -6.51, -0.97); P = 0.008] and a trend towards a reduction was observed for apolipoprotein A [WMD = -2.91 (95% CI: -5.98, 0.08); P = 0.057]. Walnut-enriched diets did not lead to significant differences in weight change (kg) compared with control diets [WMD = -0.12 (95% CI: -2.12, 1.88); P = 0.90], systolic blood pressure (mm Hg) [WMD = -0.72 (95% CI: -2.75, 1.30); P = 0.48], or diastolic blood pressure (mm Hg) [WMD = -0.10 (95% CI: -1.49, 1.30); P = 0.88]. Conclusions: Incorporating walnuts into the diet improved blood lipid profile without adversely affecting body weight or blood pressure.
Guan, V.X., Y.C. Probst, E.P. Neale, M.J. Batterham, L.C. Tapsell, 2018. Identifying usual food choices at meals in overweight and obese study volunteers: implications for dietary advice. Br J Nutr. 120(4):472-480. doi: 10.1017/S0007114518001587.
Understanding food choices made for meals in overweight and obese individuals may aid strategies for weight loss tailored to their eating habits. However, limited studies have explored food choices at meal occasions. The aim of this study was to identify the usual food choices for meals of overweight and obese volunteers for a weight-loss trial. A cross-sectional analysis was performed using screening diet history data from a 12-month weight-loss trial (the HealthTrack study). A descriptive data mining tool, the Apriori algorithm of association rules, was applied to identify food choices at meal occasions using a nested hierarchical food group classification system. Overall, 432 breakfasts, 428 lunches, 432 dinners and 433 others (meals) were identified from the intake data (n 433 participants). A total of 142 items of closely related food clusters were identified at three food group levels. At the first sub-food group level, bread emerged as central to food combinations at lunch, but unprocessed meat appeared for this at dinner. The dinner meal was characterised by more varieties of vegetables and of foods in general. The definitions of food groups played a pivotal role in identifying food choice patterns at main meals. Given the large number of foods available, having an understanding of eating patterns in which key foods drive overall meal content can help translate and develop novel dietary strategies for weight loss at the individual level.
