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Research Nut: Mixed Nuts

Should we go nuts about nuts?

Rohrmann, S., D. Faeh, 2013. Should we go nuts about nuts? BMC Medicine. 11:165.

Since the beginning of the 1990s, increasing evidence supports beneficial effects of nut consumption on health. A new analysis of the Spanish PREDIMED trial, published in BMC Medicine, has expanded our knowledge. The study showed that individuals eating nuts more than three times per week died less often from cardiovascular disease and cancer than non-consumers. The study also adds an important finding that previous epidemiological studies could not provide: a protective effect on premature mortality was only seen in the intervention group in which nut consumption increased during the 4.8 years of follow-up, not in the intervention group with additional olive oil consumption or in the control group. Nut consumption actually decreased during follow-up in the latter two groups. Questions remain to be answered on the quantity of nuts to be consumed for health benefits, on possible mechanisms of action, and on whether some types of nuts should be favored.

Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial.

Guasch-Ferré, M., M. Bulló, M.Á. Martínez-González, E. Ros, D. Corella, R. Estruch, M. Fitó, F. Arós, J. Wärnberg, M. Fiol, J. Lapetra, E. Vinyoles, R.M. Lamuela-Raventós, L. Serra-Majem, X. Pintó, V. Ruiz-Gutiérrez, J. Basora, J. Salas-Salvadó, on behalf of the PREDIMED study group, 2013. Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial. BMC Med. 11:164.

Background: Prospective studies in non-Mediterranean populations have consistently related increasing nut consumption to lower coronary heart disease mortality. A small protective effect on all-cause and cancer mortality has also been suggested. To examine the association between frequency of nut consumption and mortality in individuals at high cardiovascular risk from Spain, a Mediterranean country with a relatively high average nut intake per person. Methods: We evaluated 7,216 men and women aged 55 to 80 years randomized to 1 of 3 interventions (Mediterranean diets supplemented with nuts or olive oil and control diet) in the PREDIMED (‘PREvención con DIeta MEDiterránea’) study. Nut consumption was assessed at baseline and mortality was ascertained by medical records and linkage to the National Death Index. Multivariable-adjusted Cox regression and multivariable analyses with generalized  estimating equation models were used to assess the association between yearly repeated measurements of nut consumption and mortality. Results: During a median follow-up of 4.8 years, 323 total deaths, 81 cardiovascular deaths and 130 cancer deaths occurred. Nut consumption was associated with a significantly reduced risk of all-cause mortality (P for trend <0.05, all). Compared to non-consumers, subjects consuming nuts >3 servings/week (32% of the cohort) had a 39% lower mortality risk (hazard ratio (HR) 0.61; 95% CI 0.45 to 0.83). A similar protective effect against cardiovascular and cancer mortality was observed. Participants allocated to the Mediterranean diet with nuts group who consumed nuts >3 servings/week at baseline had the lowest total mortality risk (HR 0.37; 95% CI 0.22 to 0.66). Conclusions: Increased frequency of nut consumption was associated with a significantly reduced risk of mortality in a Mediterranean population at high cardiovascular risk.

Threshold dose distributions for 5 major allergenic foods in children.

Blom, W.M., B.J. Vlieg-Boerstra, A.G. Kruizinga, S. van der Heide, G.F. Houben, A.E.J. Dubois, 2013. Threshold dose distributions for 5 major allergenic foods in children. J Allergy Clin Immunol. 131:172-9.

Background: For most allergenic foods, insufficient threshold dose information within the population restricts the advice on levels of unintended allergenic foods which should trigger precautionary labeling on prepackaged foods. Objective: We wanted to derive threshold dose distributions for major allergenic foods and to elaborate the protein doses at which a proportion of the allergic population is likely to respond. Methods: For 7 allergenic foods double-blind, placebo-controlled food challenges (DBPCFCs) with a positive outcome for allergic reactions were selected from the clinical database of children routinely tested to diagnose food allergy at the University Medical Center Groningen. For each allergen 2 population threshold distributions were determined with the individual minimal eliciting dose and the preceding dose of each DBPCFC for objective symptoms and any symptom (either subjective or objective). Results: Individual positive DBPCFCs were available for peanut (n = 135), cow’s milk (n = 93), hen’s egg (n = 53), hazelnut (n = 28), and cashew nut (n = 31). Fewer children were challenged with soy (n = 10) or walnut (n = 13). Threshold dose distributions showed a good statistical and visual fit. The protein dose at which 5% of the allergic population is likely to respond with objective reactions was 1.6 mg for peanut, 1.1 mg for cow’s milk, 1.5 mg for hen’s egg, 7.4 mg for cashew nut, and 0.29 mg for hazelnut. Thresholds for any symptom were on average 2 to 6 times lower than for objective symptoms. The 95% upper and lower confidence intervals of the threshold distributions were overlapping. The peanut threshold distribution on objective symptoms was similar to the distribution of another European center. Conclusions: Threshold distribution curves and eliciting doses are a powerful tool to compare different allergenic foods and for informing policy on precautionary labeling.

Estimated daily flavonoid and stilbene intake from fruits, vegetables, and nuts and associations with lipid profiles in Chinese adults.

Li, G., Y. Zhu, Y. Zhang, J. Lang, Y. Chen, W. Ling, 2013. Estimated daily flavonoid and stilbene intake from fruits, vegetables, and nuts and associations with lipid profiles in Chinese adults. J Acad Nutr Diet. 113:786-794.

Background: The scientific evidence for the association of daily flavonoid and stilbene intakes with cardiovascular risk factors in Chinese adults has not been reported previously. Objective: The aim of the study was to assess daily flavonoid and stilbene intakes and evaluate these compounds’ association with cardiovascular risk factors such as serum lipids and carotid intima–media thickness in Chinese adults. Design: A total of 1,393 subjects participated in this cross-sectional study from July 2008 to January 2010 in China. Dietary flavonoid and stilbene intakes as well as overall dietary intakes from foods and beverages were assessed with a quantitative food frequency questionnaire. Anthropometric measurements and cardiovascular risk factors including serum lipids, uric acid, and carotid intima–media thickness were examined. The relationship between flavonoids and stilbene intakes and these cardiovascular risk factors was examined using either partial correlation coefficients or analysis of covariance. Results: The richest sources of flavonoids and stilbenes were the fruit group including apple, plum, pear, and peach, followed by the vegetable group containing lotus root and taro. The daily intake of total flavonoids, anthocyanidins, flavonols, flavones, isoflavones, and stilbene were 165.6 mg/day, 27.6 mg/day, 123.7 mg/day, 10.7 mg/day, 3.7 mg/day, and 0.3 mg/day, respectively. Higher daily consumption of anthocyanidins was associated with elevated serum high-density lipoprotein cholesterol (HDL-C) concentrations (P trend=0.001), and higher total flavonoid and flavonol intakes were associated with lower serum triglycerides (TG) concentrations (P trend=0.020 and P trend=0.035, respectively) and TG/HDL-C ratios (P trend=0.040 and P trend=0.045, respectively) in female subjects. These significant relationships were not found in male subjects. Conclusions: The daily intakes of flavonoid and stilbene were estimated in the present study, and higher dietary flavonoid intake was associated with improving lipid profile in Chinese women. The results indicate that dietary flavonoids may have beneficial effect on preventing cardiovascular diseases.

Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: The PREDIMED study.

Ibarrola-Jurado, N, M. Bulló, M. Guasch-Ferré, E. Ros, M.A. Martínez-González, D. Corella, M. Fiol, J. Wärnberg, R. Estruch, P. Román, F. Arós, E. Vinyoles, L. Serra-Majem, X. Pintó, M.I. Covas, J. Basora, J. Salas-Salvadó, on behalf of the PREDIMED Study Investigators, 2013. Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: The PREDIMED study. PLoS ONE 8(2): e57367. doi:10.1371/journal.pone.0057367.

Introduction: Prospective studies have consistently suggested that nut consumption is inversely related to fatal and nonfatal coronary heart disease. Limited data are available on the epidemiological associations between nut intake and cardiometabolic risk factors. Objective: To evaluate associations between frequency of nut consumption and prevalence of cardiometabolic risk factors [obesity, metabolic syndrome (MetS), type-2 diabetes, hypertension, and dyslipidemia] in a Mediterranean population at high cardiovascular risk. Materials and Methods: Cross-sectional study of 7,210 men and women (mean age, 67 y) recruited into the PREDIMED study. MetS was defined by the harmonized ATPIII and IDF criteria. Diabetes and hypertension were assessed by clinical diagnosis and dyslipidemia (high triglycerides, low HDL-cholesterol, and hypercholesterolemia) by lipid analyses. Nut consumption was assessed using a validated food frequency questionnaire and categorized as <1, 1–3, and >3 servings/wk. Control of confounding was done with multivariate logistic regression. Results: Compared to participants consuming <1 serving/wk of nuts, those consuming >3 servings/wk had lower adjusted odds ratios (OR) for obesity (0.61, 95% confidence interval 0.54 to 0.68; P-trend <0.001), MetS (0.74, 0.65 to 0.85; P-trend, 0.001), and diabetes (0.87, 0.78 to 0.99; P-trend = 0.043). Higher nut consumption was also associated with lower risk of the abdominal obesity MetS criterion (OR 0.68, 0.60 to 0.79; P-trend <0.001). No significant associations were observed for the MetS components high blood pressure, dyslipidemia, or elevated fasting glucose. Conclusions: Nut consumption was inversely associated with the prevalence of general obesity, central obesity, MetS, and diabetes in subjects at high cardiovascular risk.

 

Phytosterol content and fatty acid pattern of ten different nut types.

Kornsteiner-Krenn, M., K.-H. Wagner, I. Elmadfa, 2013. Phytosterol content and fatty acid pattern of ten different nut types. International Journal for Vitamin and Nutrition Research. 83:263-270. 

Ten different nut kinds (almonds, Brazil nuts, cashews, hazelnuts, macadamias, peanuts, pecans, pine nuts, pistachios, and walnuts) were evaluated for their total oil and phytosterol content as well as their fatty acid composition. The total oil content was the predominant component; mean values oscillated between 45.2 % (cashews) and 74.7 % (macadamias). Mean total phytosterol content ranged from 71.7 mg (Brazil nuts) to 271.9 mg (pistachios) per 100 g oil. ß-sitosterol was the major sterol (mean >71.7 mg/100 g oil) followed by minor contents of campesterol, ergosterol, and stigmasterol. Almonds, cashews, hazelnuts, macadamias, and pistachios were high in monounsaturated fatty acids (MUFA; > 55 %). MUFA- and polyunsaturated fatty acid (PUFA)-rich nuts were peanuts and pecans, whereas Brazil nuts, pine nuts, and walnuts had the highest PUFA content (> 50 %); the high unsaturated/saturated fatty acid ratio ranged from 4.5 to 11.8. However, the fatty acid pattern of every nut is unique.

Primary prevention of cardiovascular disease with a Mediterranean diet.

Estruch, R., E. Ros, J. Salas-Salvadó, M.-I. Covas, D. Corella, F. Arós, E. Gómez-Gracia, V. Ruiz-Gutiérrez, M. Fiol, J. Lapetra, R.M. Lamuela-Raventos, L. Serra-Majem, X. Pintó, J. Basora, M.A. Muñoz, J.V. Sorlí, J.A. Martínez, M.A. Martínez-González, for the PREDIMED Study Investigators, 2013. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. DOI: 10.1056/NEJMoa1200303.

Background: Observational cohort studies and a secondary prevention trial have shown an inverse association between adherence to the Mediterranean diet and cardiovascular risk. We conducted a randomized trial of this diet pattern for the primary prevention of cardiovascular events. Methods: In a multicenter trial in Spain, we randomly assigned participants who were at high cardiovascular risk, but with no cardiovascular disease at enrollment, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). Participants received quarterly individual and group educational sessions and, depending on group assignment, free provision of extra-virgin olive oil, mixed nuts, or small nonfood gifts. The primary end point was the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). On the basis of the results of an interim analysis, the trial was stopped after a median follow-up of 4.8 years. Results: A total of 7447 persons were enrolled (age range, 55 to 80 years); 57% were women. The two Mediterranean-diet groups had good adherence to the intervention, according to self-reported intake and biomarker analyses. A primary end-point event occurred in 288 participants. The multivariable-adjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.54 to 0.92) and 0.72 (95% CI, 0.54 to 0.96) for the group assigned to a Mediterranean diet with extra-virgin olive oil (96 events) and the group assigned to a Mediterranean diet with nuts (83 events), respectively, versus the control group (109 events). No diet-related adverse effects were reported. Conclusions: Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events.

A 14-Item Mediterranean diet assessment tool and obesity indexes among high-risk subjects: The PREDIMED Trial.

Martínez-González, M.A., A. García-Arellano, E. Toledo, J. Salas-Salvado´, P. Buil-Cosiales, D. Corella, M.I. Covas, H. Schrőder, F. Arós, E. Gómez-Gracia, M. Fiol, V. Ruiz-Gutiérrez, J. Lapetra, R.M. Lamuela-Raventos, L. Serra-Majem, X. Pintó, M.A. Muñoz, J. Wärnberg, E. Ros, R. Estruch, for the PREDIMED Study Investigators, 2012. A 14-Item Mediterranean diet assessment tool and obesity indexes among high-risk subjects: The PREDIMED Trial. PLoS ONE 7(8): e43134. doi:10.1371/journal.pone.0043134

Objective: Independently of total caloric intake, a better quality of the diet (for example, conformity to the Mediterranean diet) is associated with lower obesity risk. It is unclear whether a brief dietary assessment tool, instead of full-length comprehensive methods, can also capture this association. In addition to reduced costs, a brief tool has the interesting advantage of allowing immediate feedback to participants in interventional studies. Another relevant question is which individual items of such a brief tool are responsible for this association. We examined these associations using a 14-item tool of adherence to the Mediterranean diet as exposure and body mass index, waist circumference and waist-to-height ratio (WHtR) as outcomes. Design: Cross-sectional assessment of all participants in the ‘‘PREvención con DIeta MEDiterránea’’ (PREDIMED) trial. Subjects: 7,447 participants (55–80 years, 57% women) free of cardiovascular disease, but with either type 2 diabetes or ≥3 cardiovascular risk factors. Trained dietitians used both a validated 14-item questionnaire and a full-length validated 137-item food frequency questionnaire to assess dietary habits. Trained nurses measured weight, height and waist circumference. Results: Strong inverse linear associations between the 14-item tool and all adiposity indexes were found. For a two-point increment in the 14-item score, the multivariable-adjusted differences in WHtR were -.0066 (95% confidence interval, –0.0088 to -0.0049) for women and –0.0059 (–0.0079 to –0.0038) for men. The multivariable-adjusted odds ratio for a WHtR>0.6 in participants scoring ≥10 points versus ≤7 points was 0.68 (0.57 to 0.80) for women and 0.66 (0.54 to 0.80) for men. High consumption of nuts and low consumption of sweetened/carbonated beverages presented the strongest inverse associations with abdominal obesity. Conclusions: A brief 14-item tool was able to capture a strong monotonic inverse association between adherence to a good quality dietary pattern (Mediterranean diet) and obesity indexes in a population of adults at high cardiovascular risk.

Polyphenol-rich foods in the Mediterranean diet are associated with better cognitive function in elderly subjects at high cardiovascular risk.

Valls-Pedret, C., R.M. Lamuela-Raventos, R.M., A. Medina-Remon, M. Quintana, D. Corella, X. Pinto, M.A. Martınez-Gonzalez, R. Estruch, E. Ros, 2012. Polyphenol-rich foods in the Mediterranean diet are associated with better cognitive function in elderly subjects at high cardiovascular risk. Journal of Alzheimer’s Disease. 29:773–782.

Brain oxidative processes play a major role in age-related cognitive decline, thus consumption of antioxidant-rich foods might help preserve cognition. Our aim was to assess whether consumption of antioxidant-rich foods in the Mediterranean diet relates to cognitive function in the elderly. In asymptomatic subjects at high cardiovascular risk (n = 447; 52% women; age 55–80 y) enrolled in the PREDIMED study, a primary prevention dietary-intervention trial, we assessed food intake and cardiovascular risk profile, determined apolipoprotein E genotype, and used neuropsychological tests to evaluate cognitive function. We also measured urinary polyphenols as an objective biomarker of intake. Associations between energy-adjusted food consumption, urinary polyphenols, and cognitive scores were assessed by multiple linear regression models adjusted for potential confounders. Consumption of some foods was independently related to better cognitive function. The specific associations [regression coefficients (95% confidence intervals)] were: total olive oil with immediate verbal memory [0.755 (0.151–1.358)]; virgin olive oil and coffee with delayed verbal memory [0.163 (0.010–0.316) and 0.294 (0.055–0.534), respectively];walnuts with working memory [1.191 (0.061–2.322)]; and wine with Mini-Mental State Examination scores [0.252 (0.006–0.496)]. Urinary polyphenols were associated with better scores in immediate verbal memory [1.208 (0.236–2.180)]. Increased consumption of antioxidant-rich foods in general and of polyphenols in particular is associated with better cognitive performance in elderly subjects at high cardiovascular risk. The results reinforce the notion that Mediterranean diet components might counteract age-related cognitive decline.

Nut consumption and incidence of metabolic syndrome after 6-year follow-up: the SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) cohort.

Fernández-Montero A., M. Bes-Rastrollo, J.J. Beunza, M.T. Barrio-Lopez, C. de la Fuente-Arrillaga, L. Moreno-Galarraga, M.A. Martínez-González, 2012. Nut consumption and incidence of metabolic syndrome after 6-year follow-up: the SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) cohort.  Public Health Nutr. 23:1-9. [Epub ahead of print]

OBJECTIVE: To assess the long-term relationship between tree nut consumption and the risk of developing metabolic syndrome (MetS). DESIGN:  Nut consumption was collected using a validated 136-item FFQ. The MetS was defined according to the International Diabetes Federation and American Heart Association/National Heart, Lung, and Blood Institute harmonizing definition. The association between nut consumption and MetS was assessed with logistic regression models adjusting for potential confounders. We compared the incidence of MetS between extreme categories of nut intake (≥2 servings/week v. never/almost never) after 6 years of follow-up. SETTING:  The SUN Project (Seguimiento Universidad de Navarra, University of Navarra Follow-up) is a prospective cohort study, formed of Spanish university graduates. Information is gathered by mailed questionnaires collected biennially. Nut consumption and MetS information was collected by self-reported data. SUBJECTS: Participants (n 9887) initially free of MetS or diabetes and followed up for a minimum of 6 years were included. RESULTS:  We observed 567 new cases of MetS during follow-up. Participants who consumed nuts ≥2 servings/week presented a 32 % lower risk of developing MetS than those who never/almost never consumed (adjusted OR = 0·68, 95 % CI 0·50, 0·92). The inverse association was stronger among participants who were health professionals. CONCLUSIONS:  Nut consumption was significantly associated with lower risk of developing MetS after a 6-year follow-up period in a cohort of Spanish graduates