Joseph, J.A., B. Shukitt-Hale, L.M. Willis, 2009. Grape juice, berries, and walnuts affect brain aging and behavior. J. Nutr. 139: 1813S–1817S.
Numerous studies have indicated that individuals consuming a diet containing high amounts of fruits and vegetables exhibit fewer age-related diseases such as Alzheimer’s disease. Research from our laboratory has suggested that dietary supplementation with fruit or vegetable extracts high in antioxidants (e.g. blueberries, strawberries, walnuts, and Concord grape juice) can decrease the enhanced vulnerability to oxidative stress that occurs in aging and these reductions are expressed as improvements in behavior. Additional mechanisms involved in the beneficial effects of fruits and vegetables include enhancement of neuronal communication via increases in neuronal signaling and decreases in stress signals induced by oxidative/inflammatory stressors (e.g. nuclear factor kB). Moreover, collaborative findings indicate that blueberry or Concord grape juice supplementation in humans with mild cognitive impairment increased verbal memory performance, thus translating our animal findings to humans. Taken together, these results suggest that a greater intake of high-antioxidant foods such as berries, Concord grapes, and walnuts may increase “health span” and enhance cognitive and motor function in aging.
Casas-Agustench, P., P. Lopez-Uriarte, M. Bullo’, E. Ros, J.J. Cabre’-Vila, J. Salas-Salvado’, 2009. Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome. Nutrition, Metabolism & Cardiovascular Diseases. doi:10.1016/j.numecd.2009.08.005.
Background and aims: Knowledge of the effect of nut consumption on metabolic syndrome (MetS) components is limited. We assessed the effects of nut intake on adiposity, serum lipids, insulin resistance, and inflammatory biomarkers in patients with MetS. Methods and results: In a randomized, parallel-group, 12-week feeding trial, 50 patients with MetS were given recommendations for a healthy diet with or without supplementation with 30 g/day of raw nuts (15 g walnuts, 7.5 g almonds and 7.5 g hazelnuts) (Nut and Control diet groups, respectively). Adiposity measures, serum lipids, insulin, Homeostasis Model Assessment (HOMA), interleukin-6 (IL-6) and other inflammatory biomarkers, and 48-h fecal fat were determined basally and at study’s completion. Moderate weight loss, decreased adiposity, and lower blood pressure occurred similarly after both diets. The Control, but not the Nut diet, was associated with significant (P < 0.05) reduction of LDL-cholesterol, with mean changes of -0.36 versus -0.13 mmol/L, respectively (between-group differences, P=0.154). The Nut diet reduced fasting insulin by 2.60 µU/mL (95% CI, -4.62 to -0.59) and HOMA-insulin resistance by 0.72 (-1.28 to -0.16) (P < 0.05 versus Control diet; both). Among inflammatory markers, the Nut diet resulted in changes of median plasma IL-6 of -1.1 ng/L (-2.7 to -0.1; P=0.035 versus Control diet), but adjustment for weight loss attenuated the significance of the association. Stool fat decreased with the Control diet and slightly increased with the Nut diet (P < 0.05 for between-group differences). Conclusion: Patients with MetS show decreased lipid responsiveness but improved insulin sensitivity after daily intake of 30 g of mixed nuts.
Bes-Rastrollo, M., N.M. Wedick, M.A. Martinez-Gonzalez, T.Y. Li, L. Sampson, F.B. Hu, 2009. Prospective study of nut consumption, long-term weight change, and obesity risk in women. Am J Clin Nutr 89:1-7.
Background: Data concerning the long-term association between nut consumption and weight change in a free-living population are sparse. Objective: The objective was to determine the relation between nut consumption and long-term weight change. Design: The participants were 51,188 women in the Nurses’ Health Study II aged 20-45 y, who had no cardiovascular disease, diabetes, or cancer. We prospectively evaluated the dietary intake of nuts and subsequent weight changes from 1991 to 1999. Results: Women who reported eating nuts _2 times/wk had a slightly less mean (6 SE) weight gain (5.04 6 0.12 kg) than did women who rarely ate nuts (5.55 6 0.04 kg) (P for trend , 0.001). For the same comparison, when total nut consumption was subdivided into peanuts and tree nuts, the results were similar (i.e., less weight gain in women eating either peanuts or tree nuts _2 times/wk). The results were similar in normal-weight, overweight, and obese participants. In multivariate analyses in which lifestyle and other dietary factors were controlled for, we found that greater nut consumption (_2 times/wk compared with never/almost never) was associated with a slightly lower risk of obesity (hazard ratio: 0.77; 95% CI: 0.57, 1.02; P for trend ¼ 0.003). Conclusions: Higher nut consumption was not associated with greater body weight gain during 8 y of follow-up in healthy middle aged women. Instead, it was associated with a slightly lower risk of weight gain and obesity. The results of this study suggest that incorporating nuts into diets does not lead to greater weight gain and may help weight control.
Alasalvar, C., F. Shahidi, 2009. Natural antioxidants in tree nuts. Eur. J. Lipid Sci. Technol. 111:1056-1062
The levels of natural antioxidants and phytochemicals present in tree nuts are reported. Where possible, the health claims by Food and Drug Administration and European Food Safety Authority and health effects of tree nuts are provided. The content and recommended dietary allowances of nutrient antioxidants (such as vitamins A, C, E, and the mineral selenium) present in various tree nuts are compared. Antioxidant activity and phytochemicals present among tree nuts have been thoroughly reviewed. Research findings from over 65 references, many of which have been published within the last 10 years, have been compiled and reported.
Raw, D., B. Lockwood, 2009. The health benefits of nuts. NUTRAfoods. 8(3)7-14.
Overall, nuts can belp reduce the certain risk factors associated with CVD and other chronic diseases, helping to prevent disease and promote health.
Li, T.Y., A.M. Brennan, N.M. Wedick, C. Mantzoros, N. Rifai, F.B. Hu, 2009. Regular Consumption of Nuts Is Associated with a Lower Risk of Cardiovascular Disease in Women with Type 2 Diabetes. J. Nutr.139:1333-1338.
Higher nut consumption has been associated with lower risk of coronary heart disease (CHD) events in several epidemiologic studies. The study examined the association between intake of nuts and incident cardiovascular disease (CVD) in a cohort of women with type 2 diabetes. For the primary analysis, there were 6309 women with type 2 diabetes who completed a validated FFQ every 2-4 y between 1980 and 2002 and were without CVD or cancer at study entry. Major CVD events included incident myocardial infarction (MI), revascularization, and stroke. During 54,656 person-years of follow-up, there were 452 CHD events (including MI and revascularization) and 182 incident stroke cases. Frequent nut and peanut butter consumption was inversely associated with total CVD risk in age-adjusted analyses. After adjustment for conventional CVD risk factors, consumption of at least 5 servings/wk of nuts or peanut butter [serving size, 28 g (1 ounce) for nuts and 16 g (1 tablespoon) for peanut butter] was significantly associated with a lower risk of CVD (relative risk = 0.56; 95% CI: 0.36-0.89). Furthermore, when we evaluated plasma lipid and inflammatory biomarkers, we observed that increasing nut consumption was significantly associated with a more favorable plasma lipid profile, including lower LDL cholesterol, non-HDL cholesterol, total cholesterol, and apolipoprotein-B-100 concentrations. However, we did not observe significant associations for HDL cholesterol or inflammatory markers. These data suggest that frequent nut and peanut butter consumption is associated with a significantly lower CVD risk in women with type 2 diabetes.
Velliquette, R.A., P.J. Gillies, P.M. Kris-Etherton, J.W. Green, G. Zhao, J.P. Vanden Heuvel, 2009. Regulation of human stearoyl-CoA desaturase by omega-3 and omega-6 fatty acids: Implications for the dietary management of elevated serum triglycerides. Journal of Clinical Lipidology. 3:281-288.
Background: Polyunsaturated fatty acids lower serum triglycerides by a mechanism that may involve the inhibition of stearoyl-CoA desaturase (SCD). Objective: We sought to evaluate the effects of serum fatty acids on 1) the SCD index in a controlled clinical setting, and 2) SCD regulation in Hep G2 cells. Methods: The SCD index was determined in 23 subjects randomly sequenced through 3 diets for 6 weeks in a crossover study. Diets were variably enriched with n-3 and n-6 polyunsaturated fatty acids; notably, monounsaturated fatty acids were held constant. Effects of linoleic acid (LA), α-linolenic acid (ALA), and eicosapentaenoic acid (EPA) on mRNA levels of SCD, fatty acid elongases 5 and 6 (Elovl5 and Elovl6), fatty acid synthase, carnitine palmitoyltransferase-1, and sterol response element binding protein-1c were investigated in Hep G2 cells after 24-hour incubations. Results: The SCD indexes C18:1/18:0 and C16:1/C16:0 were significantly (P < .0001) correlated with serum TG with R2 values of 0.71 and 0.58. The correlation was negatively associated with LA and positively associated with ALA. LA and EPA decreased SCD mRNA (EC50 of 0.50 and 1.67 µM), whereas ALA did not. Likewise, LA and EPA decreased sterol response element binding protein-1c mRNA (EC50 of 0.78 and 1.78 µM), but ALA did not. Similar results were observed for Elovl6. GW9662, a peroxisome proliferation activator receptor antagonist, did not obviate the effects of LA and EPA on SCD mRNA. Conclusions: Diets enriched in LA, ALA, and by metabolic inference EPA, can regulate SCD activity at the level of transcription, a nutritional intervention that may be useful in the management of increased levels of serum triglycerides in cardiometabolic disorders.
Tapsell, L.C., M.J. Batterham, G. Teuss, S.-Y. Tan, S. Dalton, C.J. Quick, L.J. Gillen, K.E. Charlton, 2009. Long-term effects of increased dietary polyunsaturated fat from walnuts on metabolic parameters in type II diabetes. European Journal of Clinical Nutrition. 63:1008–1015.
Background/Objectives: Most dietary interventions have metabolic effects in the short term, but long-term effects may require dietary fat changes to influence body composition and insulin action. This study assessed the effect of sustained high polyunsaturated fatty acids (PUFA) intake through walnut consumption on metabolic outcomes in type II diabetes. Subjects/Methods: Fifty overweight adults with non-insulin-treated diabetes (mean age 54±8.7 years) were randomized to receive low-fat dietary advice ±30 g per day walnuts targeting weight maintenance (around 2000 kcal, 30% fat) for 1 year. Differences between groups were assessed by changes in anthropometric values (body weight, body fat, visceral adipose tissue) and clinical indicators of diabetes over treatment time using the general linear model. Results: The walnut group consumed significantly more PUFA than the control (P=0.035), an outcome attributed to walnut consumption (contributing 67% dietary PUFA at 12 months). Most of the effects were seen in the first 3 months. Despite being on weight maintenance diets, both groups sustained a 1–2 kg weight loss, with no difference between groups (P=0.680). Both groups showed improvements in all clinical parameters with significant time effects (P<0.004), bar triacylglycerol levels, but these were just above normal to begin with. The walnut group produced significantly greater reductions in fasting insulin levels (P=0.046), an effect seen largely in the first 3 months. Conclusions: Dietary fat can be manipulated with whole foods such as walnuts, producing reductions in fasting insulin levels. Long-term effects are also apparent but subject to fluctuations in dietary intake if not of the disease process.
Rajaram, S., E.H. Haddad, A. Mejia, J. Sabate’, 2009. Walnuts and fatty fish influence different serum lipid fractions in normal to mildly hyperlipidemic individuals: a randomized controlled study. Am J Clin Nutr. 89(suppl):1657S-1663S.
Background: Increased consumption of n-3 (omega-3) fatty acids decreases the incidence of coronary heart disease (CHD). Objective: The objective was to determine whether walnuts (plant n-3 fatty acid) and fatty fish (marine n-3 fatty acid) have similar effects on serum lipid markers at intakes recommended for primary prevention of CHD. Design: In a randomized crossover feeding trial, 25 normal to mildly hyperlipidemic adults consumed 3 isoenergetic diets (’30% total fat and,10% saturated fat) for 4 wk each: a control diet (no nuts or fish), a walnut diet (42.5 g walnuts/10.1 mJ), or a fish diet (113 g salmon, twice/wk). Fasting blood was drawn at baseline and at the end of each diet period and analyzed for serum lipids. Results: Serum total cholesterol and LDL cholesterol concentrations in adults who followed the walnut diet (4.87 ± 0.18 and 2.77 ± 0.15 mmol/L, respectively) were lower than in those who followed the control diet (5.14 ± 0.18 and 3.06 ± 0.15 mmol/L, respectively) and those who followed the fish diet (5.33 ± 0.18 and 3.2 ± 0.15 mmol/L, respectively; P<0.0001). The fish diet resulted in decreased serum triglyceride and increased HDL-cholesterol concentrations (1.0 ± 0.11 and 1.23 ± 0.05 mmol/L, respectively) compared with the control diet (1.12 ± 0.11 and 1.19 ± 0.05 mmol/L, respectively) and the walnut diet (1.11 ± 0.11 mmol/L, P<0.05, and 1.18 ± 0.05 mmol/L, P<0.001, respectively). The ratios of total cholesterol: HDL cholesterol, LDL cholesterol:HDL cholesterol, and apolipoprotein B:apolipoprotein A-I were lower (P<0.05) in those who followed the walnut diet compared with those who followed the control and fish diets. Conclusions: Including walnuts and fatty fish in a healthy diet lowered serum cholesterol and triglyceride concentrations, respectively, which affects CHD risk favorably.
Casas-Agustench, P., P. Lo’ pez-Uriarte, M. Bullo’, E. Ros, A. Go’ mez-Flores, J. Salas-Salvado’, 2009. Acute effects of three high-fat meals with different fat saturations on energy expenditure, substrate oxidation and satiety. Clinical Nutrition 28:39-45.
Background & aims: To compare the acute effects of three fatty meals with different fat quality on postprandial thermogenesis, substrate oxidation and satiety. Methods: Twenty-nine healthy men aged between 18 and 30 years participated in a randomized crossover trial comparing the thermogenic effects of three isocaloric meals: high in polyunsaturated fatty acids from walnuts, high in monounsaturated fatty acids from olive oil, and high in saturated fatty acids from fat-rich dairy products. Indirect calorimetry was used to determine resting metabolic rate, respiratory quotient, 5-h postprandial energy expenditure and substrate oxidation. Satiety was estimated by using visual analogue scales and measuring caloric intake in a subsequent ad libitum meal. Results: Five-h postprandial thermogenesis was higher by 28% after the high-polyunsaturated meal (p = 0.039) and by 23% higher after the high-monounsaturated meal (p = 0.035) compared with the high saturated meal. Fat oxidation rates increased nonsignificantly after the two meals rich in unsaturated fatty acids and decreased nonsignificantly after the high-saturated fatty acid meal. Postprandial respiratory quotient, protein and carbohydrate oxidation, and satiety measures were similar among meals. Conclusions: Fat quality determined the thermogenic response to a fatty meal but had no clear effects on substrate oxidation or satiety.
