Ros, E., L.C. Tapsell, J. Sabaté, 2010. Nuts and berries for heart health. Curr Atheroscler Rep. 12:397–406.
Nuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds, such as L-arginine, fiber, minerals, tocopherols, phytosterols, and polyphenols. By virtue of their unique composition, nuts are likely to beneficially impact heart health. Epidemiologic studies have associated nut consumption with a reduced incidence of coronary heart disease in both genders and diabetes in women. Limited evidence also suggests beneficial effects on hypertension and inflammation. Interventional studies consistently show that nut intake has a cholesterol-lowering effect and there is emerging evidence of beneficial effects on oxidative stress, inflammation, and vascular reactivity. Blood pressure, visceral adiposity, and glycemic control also appear to be positively influenced by frequent nut consumption without evidence of undue weight gain. Berries are another plant food rich in bioactive phytochemicals, particularly flavonoids, for which there is increasing evidence of benefits on cardiometabolic risk that are linked to their potent antioxidant power.
Mattes, R.D., M.L. Dreher, 2010. Nuts and healthy body weight maintenance mechanisms. Asia Pac J Clin Nutr. 19(1):137-141.
Nuts are rich sources of multiple nutrients and phytochemicals associated with health benefits, including reduced cardiovascular disease risk. This has prompted recommendations to increase their consumption. However, they are also high in fat and are energy dense. The associations between these properties, positive energy balance and body weight raise questions about such recommendations. Numerous epidemiological and clinical studies show that nuts are not associated with weight gain. Mechanistic studies indicate this is largely attributable to the high satiety and low metabolizable energy (poor bioaccessibility leading to inefficient energy absorption) properties of nuts. Compensatory dietary responses account for 55-75% of the energy provided by nuts. Limited data suggest that routine nut consumption is associated with elevated resting energy expenditure and the thermogenic effect of feeding, resulting in dissipation of another portion of the energy they provide. Additionally, trials contrasting weight loss through regimens that include or exclude nuts indicate improved compliance and greater weight loss when nuts are permitted. Nuts may be included in the diet, in moderation, to enhance palatability, nutrient quality, and chronic disease risk reduction without compromising weight loss or maintenance.
Bolling, B.W., D.L. McKay, J. B. Blumberg, 2010. The phytochemical composition and antioxidant actions of tree nuts. Asia Pac J Clin Nutr. 19(1):117-123 117.
In addition to being a rich source of several essential vitamins and minerals, mono- and polyunsaturated fatty acids, and fiber, most tree nuts provide an array of phytochemicals that may contribute to the health benefits attributed to this whole food. Although many of these constituents remain to be fully identified and characterized, broad classes include the carotenoids, hydrolyzable tannins, lignans, naphthoquinones, phenolic acids, phytosterols, polyphenols, and tocopherols. These phytochemicals have been shown to possess a range of bioactivity, including antioxidant, antiproliferative, anti-inflammatory, antiviral, and hypocholesterolemic properties. This review summarizes the current knowledge of the carotenoid, phenolic, and tocopherol content of tree nuts and associated studies of their antioxidant actions in vitro and in human studies. Tree nuts are a rich source of tocopherols and total phenols and contain a wide variety of flavonoids and proanthocyanidins. In contrast, most tree nuts are not good dietary sources of carotenoids and stilbenes. Phenolic acids are present in tree nuts but a systematic survey of the content and profile of these compounds is lacking. A limited number of human studies indicate these nut phytochemicals are bioaccessible and bioavailable and have antioxidant actions in vivo.
O’Neil, C.E., D. R. Keast, V.L. Fulgoni, T.A. Nicklas, 2010. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004. Asia Pac J Clin Nutr. 19(1):142-150.
Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and nutrient intake and diet quality using a nationally representative sample of adults. Adults 19+ years (y) (n=13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake was determined from 24-hour diet recalls; tree nut consumers were defined as those consuming ≥¼ ounce/day (7.09 g). Means, standard errors, and ANOVA (adjusted for covariates) were determined using appropriate sample weights. Diet quality was measured using the Healthy Eating Index-2005. Among consumers, mean intake of tree nuts/tree nut butters was 1.19 + 0.04 oz/d versus 0.01 + 0.00 oz/d for non-consumers. In this study, 5.5 ± 0.3 % of individuals 19-50 y (n=7,049) and 8.4 ± 0.6 % of individuals 51+ y (n=6,243) consumed tree nuts/tree nut butters. Mean differences (p<0.01) between tree nut consumers and non-consumers of adult shortfall nutrients were: fiber (+5.0 g/d), vitamin E (+3.7 mg AT/d), calcium (+73 mg/d), magnesium (+95 mg/d), and potassium (+260 mg/d). Tree nut consumers had lower sodium intake (-157 mg/d, p<0.01). Diet quality was significantly higher in tree nut consumers (58.0±0.4 vs. 48.5±0.3, p<0.01). Tree nut consumption was associated with a higher overall diet quality score and improved nutrient intakes. Specific dietary recommendations for nut consumption should be provided for consumers.
López-Uriarte P, R. Nogués, G. Saez, M. Bulló, M. Romeu, L. Masana, C. Tormos, P. Casas-Agustench, J. Salas-Salvadó, 2010. Effect of nut consumption on oxidative stress and the endothelial function in metabolic syndrome. Clin Nutr. 29(3):373-80.
BACKGROUND & AIMS: Oxidative stress has a key role in atherosclerosis, cancer and other chronic diseases. Some bioactive compounds in nuts have been implicated in antioxidant activities. OBJECTIVE: We assessed how nut consumption affected several markers of oxidation and endothelial function (EF) in metabolic syndrome (MetS) patients. PATIENTS AND METHODS: A randomized, controlled, parallel feeding trial was conducted on 50 MetS adults who were recommended a healthy diet supplemented or not with 30 g of mixed nuts (Nut and Control groups, respectively) every day for 12 weeks. The plasma antioxidant capacity (AC), oxidized LDL (oxLDL), conjugated diene (CD) formation, urine 8-isoprostanes, DNA damage assessed by yield of urine 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxo-dG), and EF assessed by peripheral artery tonometry (PAT) and biochemical markers, were measured at baseline and the end of the intervention. RESULTS: No significant differences in changes between groups were observed in AC, oxLDL, CD, 8-isoprostanes or EF during the intervention, whereas the reduction in DNA damage was significant in the Nut group compared to Control group (P < 0.001). CONCLUSION: Nut consumption has no deleterious effect on lipid oxidation. The decrease in DNA damage observed in this study could contribute to explain the beneficial effects of regular nut consumption on some MetS features and several chronic diseases.
Kendall, C.W.C., A. Esfahani, J. Truan, K. Srichaikul, D.J.A. Jenkins, 2010. Health benefits of nuts in prevention and management of diabetes. Asia Pac J Clin Nutr. 19(1):110-116.
The effects of tree nuts on risk factors for coronary heart disease (CHD), in particular blood lipids, have been investigated in a number of studies and the beneficial effects are now recognized. The beneficial effects of nuts on CHD in cohort studies have also been clearly demonstrated. However, while there is also reason to believe the unique micro- and macronutrient profiles of nuts may help to control blood glucose levels, relatively few studies have investigated their role in diabetes control and prevention. Nuts are low in available carbohydrate, have a healthy fatty acid profile, and are high in vegetable protein, fiber and magnesium. Acute feeding studies indicate that when eaten alone nuts have minimal effects on raising postprandial blood glucose levels. In addition, when nuts are consumed with carbohydrate rich foods, they blunt the postprandial glycemic response of the carbohydrate meal. Despite the success of these acute studies, only a limited number of trials have been conducted with nuts in type 2 diabetes. These studies have either been of insufficient duration to observe changes in HbA1c, as the standard measure of glycemic control, or have been underpowered. Therefore, more long-term clinical trials are required to examine the role of nuts on glycemic control in patients with prediabetes and diabetes. Overall, there are good reasons to justify further exploration of the use of nuts in the prevention of diabetes and its microand macrovascular complications.
Casas-Agustench, P., M. Bulló, J. Salas-Salvadó, 2010. Nuts, inflammation and insulin resistance. Asia Pac J Clin Nutr. 19(1):124-130.
The beneficial effects of nut consumption on cardiovascular disease (CVD) have been widely documented. These protective effects are mainly attributed to the role of nuts in the metabolism of lipids and lipoproteins. As chronic inflammation is a key early stage in the atherosclerotic process that predicts future CVD events and is closely related to the pathogenesis of insulin resistance, many recent studies have focused on the potential effect of nut consumption on inflammation and insulin resistance. Through different mechanisms, some components of nuts such as magnesium, fiber, α-linolenic acid, L-arginine, antioxidants and MUFA may protect against inflammation and insulin resistance. This review evaluates the epidemiologic and experimental evidence in humans demonstrating an association between nut consumption and these two emergent cardio-protective mechanisms.
Sabaté, J., M. Wien, 2010. Nuts, blood lipids and cardiovascular disease. Asia Pac J Clin Nutr. 19(1):131-136.
The aim of this paper is to evaluate nut-related epidemiological and human feeding study findings and to discuss the important nutritional attributes of nuts and their link to cardiovascular health. Frequent nut consumption has been found to be protective against coronary heart disease in five large epidemiological studies across two continents. A qualitative summary of the data from four of these studies found an 8.3% reduction in risk of death from coronary heart disease for each weekly serving of nuts. Over 40 dietary intervention studies have been conducted evaluating the effect of nut containing diets on blood lipids. These studies have demonstrated that intake of different kinds of nuts lower total and LDL cholesterol and the LDL: HDL ratio in healthy subjects or patients with moderate hypercholesterolaemia, even in the context of healthy diets. Nuts have a unique fatty acid profile and feature a high unsaturated to saturated fatty acid ratio, an important contributing factor to the beneficial health effects of nut consumption. Additional cardioprotective nutrients found in nuts include vegetable protein, fiber, α-tocopherol, folic acid, magnesium, copper, phytosterols and other phytochemicals.
Babio, N., M. Bulló, J. Basora, M.A. Martínez-González, J. Fernández-Ballart, F. Márquez-Sandoval, C. Molina, J. Salas-Salvadó; Nureta-PREDIMED Investigators, 2009. Adherence to the Mediterranean diet and risk of metabolic syndrome and its components. Nutr Metab Cardiovasc Dis. 19(8):563-70.
BACKGROUND AND AIMS: The role of diet in the aetiology of metabolic syndrome (MetS) is not well understood. The aim of the present study was to evaluate the relationship between adherence to the Mediterranean diet (MedDiet) and MetS. METHODS AND RESULTS: A cross-sectional study was conducted with 808 high cardiovascular risk participants of the Reus PREDIMED Centre. MetS was defined by the updated National Cholesterol and Education Program Adult Treatment Panel III criteria. An inverse association between quartiles of adherence to the MedDiet (14-point score) and the prevalence of MetS (P for trend<0.001) was observed. After adjusting for age, sex, total energy intake, smoking status and physical activity, participants with the highest score of adherence to the MedDiet (>/=9 points) had the lowest odds ratio of having MetS (OR [95% CI] of 0.44 [0.27-0.70]) compared to those in the lowest quartile. Participants with the highest MedDiet adherence had 47 and 54% lower odds of having low HDL-c and hypertriglyceridemia MetS criteria, respectively, than those in the lowest quartile. Some components of the MedDiet, such as olive oil, legumes and red wine were associated with lower prevalence of MetS. CONCLUSION: Higher adherence to a Mediterranean diet is associated with a significantly lower odds ratio of having MetS in a population with a high risk of cardiovascular disease.
Taylor, S.L., R.W.R. Crevel, D. Sheffield, J. Kabourek, J. Baumert, 2009. Threshold dose for peanut: Risk characterization based upon published results from challenges of peanut-allergic individuals. Food Chem Toxicol. 47:1198–1204.
Population thresholds for peanut are unknown. However, lowest- and no-observed adverse effect levels (LOAELs and NOAELs) are published for an unknown number of peanut-allergic individuals. Publications were screened for LOAELs and NOAELs from blinded, low-dose oral challenges. Data were obtained from 185 peanut-allergic individuals (12 publications). Data were analyzed by interval-censoring survival analysis and three probability distribution models fitted to it (Log-Normal, Log-Logistic, and Weibull) to estimate the ED10. All three models described the data well and provided ED10’s in close agreement: 17.6, 17.0, and 14.6 mg of whole peanut for the Log-Normal, Log-Logistic, and Weibull models, respectively. The 95% lower confidence intervals for the ED10’s were 9.2, 8.1, and 6.0 mg of whole peanut for the Log-Normal, Log-Logistic, and Weibull models, respectively. The modeling of individual NOAELs and LOAELs identified from three different types of published studies – diagnostic series, threshold studies, and immunotherapy trials – yielded significantly different whole peanut ED10’s of 11.9 mg for threshold studies, 18.0 mg for diagnostic series and 65.5 mg for immunotherapy trials; patient selection and other biases may have influenced the estimates. These data and risk assessment models provide the type of information that is necessary to establish regulatory thresholds for peanut.
