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Nut consumption, weight gain and obesity: Epidemiological evidence.

Martínez-González, M.A., M. Bes-Rastrollo, 2011. Nut consumption, weight gain and obesity: Epidemiological evidence. Nutr Metab Cardiovasc Dis. 21(Suppl 1):S40-5.

BACKGROUND AND AIMS: Short-term trials support that adding tree nuts or peanuts to usual diets does not induce weight gain. We reviewed the available epidemiological evidence on long-term nut consumption and body weight changes. We also report new results from the SUN (“Seguimiento Universidad de Navarra”) cohort. METHODS AND RESULTS: Published epidemiologic studies with ≥1-yr follow-up were located. Two published reports from large cohorts (SUN and Nurses Health Study-2) showed inverse associations between frequency of nut consumption and long-term weight changes. A beneficial effect of a Mediterranean diet supplemented with tree nuts on waist circumference was reported after 1-yr follow-up in the first 1224 high-risk participants in the PREDIMED (“PREvencion DIeta MEDiterranea”) trial. After assessing 11,895 participants of the SUN cohort, a borderline significant (p value for trend = 0.09) inverse association between baseline nut consumption and average yearly weight gain (multivariate-adjusted means = 0.32 kg/yr (95% confidence interval: 0.22-0.42) and 0.24 (0.11-0.37) kg/yr for participants with no consumption and >4 servings/week, respectively) was found after a 6-yr follow-up. CONCLUSIONS: Consumption of nuts was not associated with a higher risk of weight gain in long-term epidemiologic studies and clinical trials.

Cultural and historical aspects of Mediterranean nuts with emphasis on their attributed healthy and nutritional properties.

Salas-Salvadó J, Casas-Agustench P, Salas-Huetos A., 2011. Cultural and historical aspects of Mediterranean nuts with emphasis on their attributed healthy and nutritional properties. Nutr Metab Cardiovasc Dis. 21(Suppl 1):S1-6.

BACKGROUND AND AIMS: Nuts have been part of the human diet since prehistoric times. The aim of the present article is to describe the most important historical and cultural aspects of nut consumption throughout history. DATA SYNTHESIS: We discuss the following historical aspects of nuts originating in the Mediterranean: prehistory, the Egyptian civilization, their spread through the Mediterranean region by the Greek, Phoenician and Roman civilizations, and their reintroduction into Europe by means of the Al-Andalus culture. Particular emphasis is placed on the healthy and nutritional attributes that nuts have had throughout history. We also consider the role of the first globalization of food–the exchange of nuts between continents–and discuss the symbolism that nuts have had for humans throughout history in the context of cultural aspects of the Mediterranean region. CONCLUSIONS: Nuts and fruits are probably the earliest foods consumed by humans and are considered to be important because of their nutritional properties. Nuts have also been used in the past by different civilizations as drugs to prevent or treat several diseases.

Effect of food matrix on amandin, almond (Prunus dulcis L.) major protein, immunorecognition and recovery.

Tiwari, R.S., M. Venkatachalam, G.M. Sharma, M. Su, K.H. Roux, S.K. Sathe, 2010. Effect of food matrix on amandin, almond (Prunus dulcis L.) major protein, immunorecognition and recovery. LWT – Food Science And Technology. 43:675-83.

Amandin, the primary storage protein in almonds, contains key polypeptides recognized by  almondallergic patients. A variety of food matrices representing diverse categories of foods were analyzed to assess the effect of food matrix on amandin recognition and recovery using rabbit polyclonal antibody based immunoassays. Food matrices from dairy, nuts, and vegetables typically resulted in over-estimation of amandin. Some foods representing legumes and cereals resulted in over-estimation while others in under-estimation of amandin. The amandin recovery range was 116–198 µg/100µg (dairy) 110–292 µg/100µg (tree nuts), 43–304 µg/100µg (legumes), 106–183 µg/100µg (most cereals- with the exception of barley, whole-wheat flour, wild rice and raisin bran whole mix). Amandin recovery from spices was typically low (2–85 µg/100µg) with a few exceptions where higher recoveries were observed (121–334 µg/100µg). Salt (black and white), tea, confectionery (sugar, cocoa, dark chocolate), and fruits (1–83µg/100µg) generally resulted in lower recoveries. Tested food matrices did not adversely affect amandin immunorecognition in Western blots. The pH and the extraction buffer type affected amandin recovery. The results suggest that food matrix effects as well as extraction conditions need to be carefully evaluated when developing immunoassays for amandin detection and quantification.

Polyphenol content and antioxidant activity of California almonds depend on cultivar and harvest year.

Bolling, B.W., G. Dolnikowski, J.B. Blumberg, C.-Y. O. Chen, 2010. Polyphenol content and antioxidant activity of California almonds depend on cultivar and harvest year. Food Chem. 122:819-825.

The polyphenol content and antioxidant activity of Nonpareil, Carmel, Butte, Sonora, Fritz, Mission, and Monterey almond cultivars harvested over three seasons in California were examined. LC–MS was employed to quantify 16 flavonoids and two phenolic acids in acidified methanol extracts of almond skins. The 3-year mean polyphenol content of cultivars ranged from 4.0 to 10.7 mg/100 g almonds. Isorhamnetin-3-O-rutinoside was the most abundant flavonoid, present at 28–49% of total polyphenols among cultivars. Almonds from 2006 and 2007 had 13% fewer polyphenols than 2005, but FRAP and total phenols were comparable. Cultivar, but not season, had a differential impact on individual polyphenol synthesis. Using the results of polyphenol, total phenol, and FRAP, multivariate analysis distinguished harvest years and most cultivars with 80% confidence. Flavonoid content and antioxidant activity of almonds may be more dependent on cultivar than on seasonal difference

Effect of almond-enriched high-monounsaturated fat diet on selected markers of inflammation: a randomised, controlled, crossover study. British Journal of Nutrition.

Rajaram, S., K.M. Connell, J. Sabate´, 2010. Effect of almond-enriched high-monounsaturated fat diet on selected markers of inflammation: a randomised, controlled, crossover study. British Journal of Nutrition. 103:907–912.

Frequent consumption of nuts lowers the risk of CHD. While lowering blood lipids is one of the mechanisms for cardioprotection, the present study sought to determine whether monounsaturated fat-rich almonds also influence other CHD risk factors such as inflammation and haemostasis. This was a randomised, controlled, crossover feeding study with twenty-five healthy adults (eleven men; fourteen women), age 22–53 years. Following a 2 week run-in phase (34% energy from fat), subjects were assigned in random order to three diets for 4 weeks each: a heart-healthy control diet with no nuts (<30% energy from fat), low-almond diet and high-almond diet (10% or 20% isoenergetic replacement of control diet with almonds, respectively). Serum E-selectin was significantly lower on the high-almond diet compared with the control diet. E-selectin decreased as the percentage of energy from almonds increased (P<0·0001). C-reactive protein (CRP) was lower in both the almond diets compared with the control diet. A clear dose response was not observed for either E-selectin or CRP. There was no effect of diet on IL-6 or fibrinogen. Tissue plasminogen activator antigen was significantly lower on the control and high-almond diets compared with the low-almond diet, although the values were within normal range. In conclusion, consumption of almonds influenced a few but not all of the markers of inflammation and haemostasis. A clear dose response was not observed for any of the markers studied.

Targeted analysis of conjugated and microbial-derived phenolic metabolites in human urine after consumption of an almond skin phenolic extract.

Garrido, I., M. Urpi-Sarda, M. Monagas, C. Gómez-Cordovés, P.J. Martín-Álvarez,  R. Llorach, B. Bartolomé, C. Andrés-Lacueva, 2010. Targeted analysis of conjugated and microbial-derived phenolic metabolites in human urine after consumption of an almond skin phenolic extract. J. Nutr. 140:1799–807.

A single-blind, placebo-controlled, and randomized trial study was carried out with 16 healthy volunteers (7 men and 5 women). The test group ingested an encapsulated almond skin phenolic extract (884 mg of total polyphenols/dose) containing flavan-3-ols, flavonols, and flavanones, whereas the placebo group ingested microcrystalline cellulose. Our aim in this study was to determine changes in the urinary excretion of conjugated and microbial-derived phenolic metabolites before (-2 to 0 h) and after (0–2, 2–6, 6–10, and 10–24 h) intake of the almond polyphenols compared with the placebo group. For the test group, maximum urinary excretion of (epi)catechin and naringenin conjugates derived from phase II metabolism was attained at 2–6 h after consumption of the almond skin extract and excretions differed from the placebo group during this time period (P ≤ 0.0001). However, excretion of conjugated metabolites of isorhamnetin was highest at 10–24 h and did not differ from the placebo group during this time (P > 0.05). Hydroxyphenylvalerolactones reached maximum urinary levels at 6–10 h after consumption of almond polyphenols, and excretion differed from the placebo group during this time period (P = 0.0004). For the test group, excretions of phenolic acids (hydroxyphenylpropionic, hydroxyphenylacetic, hydroxybenzoic, and hydroxycinnamic acids) did not differ from the placebo group at any time period of urine collection (P > 0.05). The findings presented in this work provide evidence concerning the bioavailability of almond skin polyphenols considering the effects of both phase II and microbial metabolism.

Characterization of polyphenols, lipids and dietary fibre from almond skins (Amygdalus communis L.).

Mandalari, G., A. Tomaino, T. Arcoraci, M. Martorana, V. Lo Turco, F. Cacciola, G.T. Rich, C. Bisignano, A. Saija, P. Dugo, K.L. Cross, M.L. Parker, K.W. Waldron, M.S. J. Wickham, 2010. Characterization of polyphenols, lipids and dietary fibre from almond skins (Amygdalus communis L.). Journal of Food Composition and Analysis. 23:166–174.

Almond skins and blanch water are underutilized by-products of the almond processing industry. Nevertheless, they contain exploitable components that may contribute to the health benefits associated with almond consumption. We have compared natural almond skin powder (NS) prepared by a novel freeze-thawing method with blanched almond skin powder (BS). Microstructural studies were carried out, and we analyzed both types of almond skin for phenolic compounds (by HPLC), lipids (by solvent extraction), proteins (by micro-Kjeldahl), and fibre content (by the enzymatic-gravimetric AOAC method). Antioxidant activity (by measuring the reduction of the 2,2-diphenyl-1-picrylhydrazyl radical) was also monitored. We identified a combination of flavonols, flavan-3-ols, hydroxybenzoic acids and flavanones in NS, BS and in industrially obtained blanch water (BW). As expected, the total phenolic content was higher in NS compared to BW and BS, although the latter showed high antioxidant properties. Almond skins had high fibre content as well as significant amounts of lipid; both of these components may be relevant to fermentation in the large intestine. In addition, the processing of almond skins and blanch water clearly has economic potential for lowering the environmental impact of waste fill and pollution.

Almond (Prunus dulcis (Mill.) D.A. Webb) polyphenols: From chemical characterization to targeted analysis of phenolic metabolites in humans.

Bartolomé, B., M. Monagas, I. Garrido, C. Gómez-Cordovés, P.J. Martín-Álvarez, R. Lebrón-Aguilar, M. Urpí-Sardà, R. Llorach, C. Andrés-Lacueva, 2010. Almond (Prunus dulcis (Mill.) D.A. Webb) polyphenols: From chemical characterization to targeted analysis of phenolic metabolites in humans. Archives of Biochemistry and Biophysics. 501:124–133.

In this paper, a survey of our studies on almond polyphenols including their chemical characterization and further bioavailability in humans is reported. Combination of analytical techniques (LC-DAD/fluorescence, LC/ESI-MS and MALDI-TOF-MS) allowed us, for the first time, the identification of A- and B-type procyanidin, propelargonidin and prodelphinidin polymers in almond skins. Glucuronide, O-methyl glucuronide, sulfate and O-methyl sulfate derivatives of (epi)catechin, as well as the glucuronide conjugates of naringenin and isorhamnetin, and sulfate conjugates of isorhamnetin, together with conjugates of hydroxyphenylvalerolactones were detected in plasma and urine samples after the intake of almond skin polyphenols. In addition, numerous microbial-derived metabolites, including hydroxyphenylpropionic, hydroxyphenylacetic, hydroxycinnamic, hydroxybenzoic and hydroxyhippuric acids were also identified. Depending of the type of metabolite, maximum urinary excretion was attained at different time in comparison to the control group in the course of the 24-h period of urine excretion, allowing us to establish the onset of microbial metabolism.

Almond consumption and cardiovascular risk factors in adults with prediabetes.

Wien, M., D. Bleich, M. Raghuwanshi, S. Gould-Forgerite, J. Gomes, L. Monahan-Couch, K. Oda, 2010. Almond consumption and cardiovascular risk factors in adults with prediabetes. Journal of the American College of Nutrition. 29(3):189–197.

Objective: The authors tested the hypothesis that in adults with prediabetes, an almond-enriched American Diabetes Association (ADA) diet improves measures of insulin sensitivity and other cardiovascular risk factors compared with an ADA nut-free diet. Methods: Design: Randomized parallel-group trial. Setting: Outpatient dietary counseling and blood analysis. Subjects: Sixty-five adult participants with prediabetes. Intervention: Sixteen weeks of dietary modification featuring an ADA diet containing 20% of energy from almonds (approximately 2 oz per day). Measures of Outcome: Outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, TC:HDL-C, and HbA1c, which were measured at weeks 0, 8, and 16. Body weight, body mass index (BMI), waist circumference, blood pressure, and nutrient intake were measured at weeks 0, 4, 8, 12, and 16. Results: The almond-enriched intervention group exhibited greater reductions in insulin (-1.78 µU/ml vs. +1.47 µU/ml, P = 0.002), homeostasis model analysis for insulin resistance (-0.48 vs. +0.30, P = 0.007), and homeostasis model analysis for beta-cell function (-13.2 vs. +22.3, P = 0.001) compared with the nut-free control group. Clinically significant declines in LDL-C were found in the almond-enriched intervention group (-12.4 mg/dl vs. -0.4 mg/dl) as compared with the nut-free control group. No changes were observed in BMI (-0.4 vs. -0.7 kg/m2, P = 0.191), systolic blood pressure (-4.4 mm Hg vs. -3.5 mm Hg, P = 0.773), or for the other measured cardiovascular risk factors. Conclusions: An ADA diet consisting of 20% of calories as almonds over a 16-week period is effective in improving markers of insulin sensitivity and yields clinically significant improvements in LDL-C in adults with prediabetes.

Nut consumption and blood lipid levels: A pooled analysis of 25 intervention trials

Sabate´, J., K. Oda, E. Ros, 2010. Nut Consumption and Blood Lipid Levels A Pooled Analysis of 25 Intervention Trials. Arch Intern Med. 170(9):821-827.

Background: Epidemiological studies have consistently associated nut consumption with reduced risk for coronary heart disease. Subsequently, many dietary intervention trials investigated the effects of nut consumption on blood lipid levels. The objectives of this study were to estimate the effects of nut consumption on blood lipid levels and to examine whether different factors modify the effects. Methods: We pooled individual primary data from 25 nut consumption trials conducted in 7 countries among 583 men and women with normolipidemia and hypercholesterolemia who were not taking lipid-lowering medications. In a pooled analysis, we used mixed linear models to assess the effects of nut consumption and the potential interactions. Results: With a mean daily consumption of 67 g of nuts, the following estimated mean reductions were achieved: total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P<.001 for all) (to convert all cholesterol concentrations to millimoles per liter, multiply by 0.0259). Triglyceride levels were reduced by 20.6 mg/dL (10.2%) in subjects with blood triglyceride levels of at least 150 mg/dL (P<.05) but not in those with lower levels (to convert triglyceride level to millimoles per liter, multiply by 0.0113). The effects of nut consumption were dose related, and different types of nuts had similar effects on blood lipid levels. The effects of nut consumption were significantly modified by LDL-C, body mass index, and diet type: the lipid-lowering effects of nut consumption were greatest among subjects with high baseline LDL-C and with low body mass index and among those consuming Western diets. Conclusion: Nut consumption improves blood lipid levels in a dose-related manner, particularly among subjects with higher LDL-C or with lower BMI.