Casas-Agustench, P., A. Salas-Huetos, J. Salas-Salvado´, 2011. Mediterranean nuts: origins, ancient medicinal benefits and symbolism. Public Health Nutrition: 14(12A): 2296–2301.
Objective: To consider historical aspects of nuts in relation to origin and distribution, attributed medicinal benefits, symbolism, legends and superstitions. Design: Review of historical aspects of nuts. Setting: Mediterranean region. Subjects: The varieties reviewed include almonds, walnuts, hazelnuts, pine nuts and pistachios. Results and conclusions: Like other foods, nuts have a wide variety of cultural connections to the areas where they grow and to the people who live there or eat them. History, symbolism and legends reveal the ancient tradition of nuts and how they are related to the lives of our ancestors. Archaeological excavations in eastern Turkey have uncovered the existence of a non-migratory society whose economy centered on harvesting nuts. This shows that nuts have been a staple in the human diet since the beginnings of history. Moreover, since ancient times nuts have been used for their medicinal properties. They also play a role in many old legends and traditions.
Bolling, B.W., C.-Y. O. Chen, D.L. McKay, J.B. Blumberg, 2011. Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts. Nutrition Research Reviews 24:244–275
Tree nuts contain an array of phytochemicals including carotenoids, phenolic acids, phytosterols and polyphenolic compounds such as flavonoids, proanthocyanidins (PAC) and stilbenes, all of which are included in nutrient databases, as well as phytates, sphingolipids, alkylphenols and lignans, which are not. The phytochemical content of tree nuts can vary considerably by nut type, genotype, pre- and post-harvest conditions, as well as storage conditions. Genotype affects phenolic acids, flavonoids, stilbenes and phytosterols, but data are lacking for many other phytochemical classes. During the roasting process, tree nut isoflavones, flavanols and flavonols were found to be more resistant to heat than the anthocyanins, PAC and trans-resveratrol. The choice of solvents used for extracting polyphenols and phytosterols significantly affects their quantification, and studies validating these methods for tree nut phytochemicals are lacking. The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemopreventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes. While tree nut phytochemicals are bioaccessible and bioavailable in humans, the number of intervention trials conducted to date is limited. The objectives of the present review are to summarize tree nut: (1) phytochemicals; (2) phytochemical content included in nutrient databases and current publications; (3) phytochemicals affected by pre- and post-harvest conditions and analytical methodology; and (4) bioactivity and health benefits in humans.
Salas-Salvadó, J., M. Bulló, N. Babio, M.Á. Martínez-González, N. Ibarrola-Jurado, J. Basora, R. Estruch, M.I. Covas, D. Corella, F. Arós, V. Ruiz-Gutiérrez, E. Ros, and for the PREDIMED Study Investigators, 2011. Reduction in the incidence of type 2 diabetes with the Mediterranean diet results of the PREDIMED-Reus nutrition intervention randomized trial. Diabetes Care. 34:14–19.
OBJECTIVE: To test the effects of two Mediterranean diet (MedDiet) interventions versus a low-fat diet on incidence of diabetes. RESEARCH DESIGN AND METHODS: This was a three-arm randomized trial in 418 nondiabetic subjects aged 55–80 years recruited in one center (PREDIMED-Reus, northeastern Spain) of the Prevención con Dieta Mediterránea [PREDIMED] study, a large nutrition intervention trial for primary cardiovascular prevention in individuals at high cardiovascular risk. Participants were randomly assigned to education on a low-fat diet (control group) or to one of two MedDiets, supplemented with either free virgin olive oil (1 liter/week) or nuts (30 g/day). Diets were ad libitum, and no advice on physical activity was given. The main outcome was diabetes incidence diagnosed by the 2009 American Diabetes Association criteria. RESULTS: After a median follow-up of 4.0 years, diabetes incidence was 10.1% (95% CI 5.1–15.1), 11.0% (5.9–16.1), and 17.9% (11.4–24.4) in the MedDiet with olive oil group, the MedDiet with nuts group, and the control group, respectively. Multivariable adjusted hazard ratios of diabetes were 0.49 (0.25–0.97) and 0.48 (0.24–0.96) in the MedDiet supplemented with olive oil and nuts groups, respectively, compared with the control group. When the two MedDiet groups were pooled and compared with the control group, diabetes incidence was reduced by 52% (27–86). In all study arms, increased adherence to the MedDiet was inversely associated with diabetes incidence. Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity. CONCLUSIONS: MedDiets without calorie restriction seem to be effective in the prevention of diabetes in subjects at high cardiovascular risk.
Jenkins, D.J.A., C.W.C. Kendall, M.S. Banach, K. Srichaikul, E. Vidgen, S. Mitchell, T. Parker, S. Nishi, B. Bashyam, R. de Souza, C. Ireland, R.G. Josse, 2011. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care. 34(8):1706-11.
OBJECTIVE: Fat intake, especially monounsaturated fatty acid (MUFA), has been liberalized in diabetic diets to preserve HDL cholesterol and improve glycemic control, yet the exact sources have not been clearly defined. Therefore, we assessed the effect of mixed nut consumption as a source of vegetable fat on serum lipids and HbA1c in type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 117 type 2 diabetic subjects were randomized to one of three treatments for 3 months. Supplements were provided at 475 kcal per 2,000-kcal diet as mixed nuts (75 g/day), muffins, or half portions of both. The primary outcome was change in HbA1c. RESULTS: The relative increase in MUFAs was 8.7% energy on the full-nut dose compared with muffins. Using an intention-to-treat analysis (n = 117), full-nut dose (mean intake 73 g/day) reduced HbA1c (−0.21% absolute HbA1c units, 95% CI −0.30 to −0.11, P < 0.001) with no change after half-nut dose or muffin. Full-nut dose was significantly different from half-nut dose (P = 0.004) and muffin (P = 0.001), but no difference was seen between half-nut dose and muffins. LDL cholesterol also decreased significantly after full-nut dose compared with muffin. The LDL cholesterol reduction after half-nut dose was intermediate and not significantly different from the other treatments. Apolipoprotein (apo) B and the apoB:apoA1 ratio behaved similarly. Nut intake related negatively to changes in HbA1c (r = −0.20, P = 0.033) and LDL cholesterol (r = −0.24, P = 0.011). CONCLUSIONS: Two ounces of nuts daily as a replacement for carbohydrate foods improved both glycemic control and serum lipids in type 2 diabetes.
Casas-Agustench, P., P. López-Uriarte, E. Ros, M. Bulló, J. Salas-Salvadó, 2011. Nuts, hypertension and endothelial function. Nutr Metab Cardiovasc Dis. 2011 21(Suppl 1):S21-33.
BACKGROUND AND AIMS: High blood pressure (BP) is considered a major risk factor for cardiovascular disease. Among lifestyle factors, diet plays a key role in the prevention and control of high BP. Therefore, it is important to elucidate which dietary components can exert beneficial effects on BP through modulation of endothelial function (EF) or by other mechanisms. In this paper we review the role of nutrients, foods, particularly nuts, and dietary patterns on BP control. DATA SYNTHESIS: Because nuts are low in sodium and contain significant amounts of mono- and polyunsaturated fatty acids, fiber, minerals such as magnesium, potassium and calcium, and antioxidants, they have been suggested as potentially protective foods against hypertension. Limited evidence from prospective studies and clinical trials suggests that nut consumption has a beneficial effect on both BP and EF. However, BP changes were a secondary outcome in nut feeding trials and no study used ambulatory BP monitoring as the standard for BP measurements. CONCLUSIONS: Further clinical trials, ideally using ambulatory BP monitoring, are needed to establish the potential protective effect of nut consumption on hypertension and vascular reactivity.
Del Rio, D., L. Calani, M. Dall’Asta, F. Brighenti, 2011. Polyphenolic composition of hazelnut skin. J Agric Food Chem. 59(18):9935-9941.
Skins from different hazelnut samples were characterized for total polyphenol content, total antioxidant capacity (TAC), and their content in specific polyphenolic compounds. The main polyphenolic subclass, identified and quantified by means of HPLC-MS/MS, comprised monomeric and oligomeric flavan-3-ols, which accounted for more than 95% of total polyphenols. Flavonols and dihydrochalcones were 3.5% while phenolic acids were less than 1% of the total identified phenolics. The TAC values of the skin samples ranged between 0.6 and 2.2 mol of reduced iron/kg of sample, which is about 3 times the TAC of whole walnuts, 7-8 times that of dark chocolate, 10 times that of espresso coffee, and 25 times that of blackberries. By describing the profile of polyphenols present in hazelnut skins, this study provides the basis to further investigate the potential health effects of hazelnut byproduct.
Tey, S.L., R. Brown, A. Chisholm, A. Gray, S. Williams, C. Delahunty, 2011. Current guidelines for nut consumption are achievable and sustainable: a hazelnut intervention. Br J Nutr. 105:1503–1511.
Nuts are known for their hypocholesterolaemic properties; however, to achieve optimal health benefits, nuts must be consumed regularly and in sufficient quantity. It is therefore important to assess the acceptability of regular consumption of nuts. The present study examined the long-term effects of hazelnut consumption in three different forms on ‘desire to consume’ and ‘overall liking’. A total of forty-eight participants took part in this randomised cross-over study with three dietary phases of 4 weeks: 30 g/d of whole, sliced and ground hazelnuts. ‘Overall liking’ was measured in a three-stage design: a pre- and post-exposure tasting session and daily evaluation over the exposure period. ‘Desire to consume’ hazelnuts was measured during the exposure period only. Ratings were measured on a 150 mm visual analogue scale. Mean ratings of ‘desire to consume’ were 92 (SD 35) mm for ground, 108 (SD 33) mm for sliced and 116 (SD 30) mm for whole hazelnuts. For ‘overall liking’, the mean ratings were 101 (SD 29) mm for ground, 110 (SD 32) mm for sliced and 118 (SD 30) mm for whole hazelnuts. Ground hazelnuts had significantly lower ratings than both sliced (P ≤ 0.034) and whole hazelnuts (P < 0.001), with no difference in ratings between sliced and whole hazelnuts (P ≥ 0.125). For each form of nut, ratings of ‘overall liking’ and ‘desire to consume’ were stable over the exposure period, indicating that not only did the participants like the nuts, but also they wished to continue eating them. Therefore, the guideline to consume nuts on a regular basis appears to be a sustainable behaviour to reduce CVD.
V. Schmitzer, A. Slatnar, R. Veberic, F. Stampar, A. Solar, 2011. Roasting affects phenolic composition and antioxidative activity of hazelnuts (Corylus avellana L.) J Food Sci. 76(1):S14-9. doi: 10.1111/j.1750-3841.2010.01898.x.
The potential effect of skin removal and roasting on individual and total phenolic content, and on antioxidative potential of 6 hazelnut cultivars were investigated. HPLC-MS identification of individual phenolics confirmed the presence of 7 flavan-3-ols (catechin, epicatechin, 2 procyanidin dimers, and 3 procyanidin trimers), 3 flavonols (quercetin pentoside, quercetin-3-O-rhamnoside, and myricetin-3-O-rhamnoside), 2 hydrobenzoic acids (gallic acid, protocatechulic acid), and 1 dihydrochalcone (phloretin-2′-O-glucoside). Flavonols were only detected in whole hazelnut kernels. The content of individual phenolics, with the exception of gallic acid, was always highest in whole unroasted hazelnuts and was significantly reduced after skin removal. Similarly, total phenolic content and antioxidative potential decreased when skin was removed. Roasting had a significant negative effect on individual phenolics but not on the total phenolic content and antioxidative potential of kernels. From a health promoting phytochemical composition of hazelnuts the consumption of whole unroasted kernels with skins should be preferential to peeled kernels either roasted or unroasted. Practical Application: A significant reduction in the antioxidative potential and total phenolic content is detected after hazelnut skin removal but not after roasting, suggesting that hazelnut kernels should be consumed whole. In hazelnut skin, many phenolic compounds are located, which are not present in flesh and, therefore, the health properties of hazelnuts are strongly affected by skin removal. Thermal processing and roasting conditions used in this study had a lesser effect on the individual phenolic composition of the kernel and thus roasted and unroasted hazelnuts without skin contain comparable amounts of health promoting compounds.
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.
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.
