Sala-Vila, A., M. Cofán, A. Pérez-Heras, I. Núñez, R. Gilabert, M. Junyent, R. Mateo-Gallego, A. Cenarro, F. Civeira, E. Ros, 2010. Fatty acids in serum phospholipids and carotid intima-media thickness in Spanish subjects with primary dyslipidemia. Am J Clin Nutr. 92:186-193.
Background: Low rates of incident ischemic heart disease (IHD) and cardiac death occur in Spain despite a high prevalence of cardiovascular risk factors. High consumption of unsaturated fatty acid–rich foods, such as olive oil, nuts, and seafood, might underlie this paradox. Objective: We investigated whether serum phosphatidylcholine enrichment in oleic, linoleic, α-linolenic, and n-3 (omega-3) long-chain polyunsaturated fatty acids (as biomarkers of olive oil, seed oil, walnut, and fish intake, respectively) relate to carotid atherosclerosis in Spanish subjects at risk of IHD. Design: In a cross-sectional study, we measured fatty acid concentrations in serum phosphatidylcholine and measured carotid intima-media thickness (IMT) by using ultrasound in 451 asymptomatic subjects (261 men, 190 women; mean age: 45 y) with primary dyslipidemia. Main and secondary outcomes were mean and maximum IMT in the common carotid artery (CCA) and other carotid segments, respectively. Results: Phosphatidylcholine fatty acid composition was similar to that reported for other Spanish populations. Multiple regression analyses showed that proportions of oleic and docosahexaenoic acids were inversely related to mean CCA IMT (P < 0.02, all) after adjustment for several confounders. In similar models, a-linolenic acid related inversely to mean and maximum internal carotid artery IMT (P < 0.05 for all). Linoleic and eicosapentaenoic acids were unrelated to IMT. Conclusions: Higher phospholipid proportions of oleic, α-linolenic, and docosahexaenoic acids showed inverse associations with IMT at specific carotid segments in subjects with primary dyslipidemia. High intakes of healthy fats might explain, in part, the Spanish paradox of low IHD rates in the face of a high burden of cardiovascular risk factors.
Sala-Vila, A., M. Cofán, I. Núñez, R. Gilabert, M. Junyent, E. Ros, 2010. Carotid and femoral plaque burden is inversely associated with the α-linolenic acid proportion of serum phospholipids in Spanish subjects with primary dyslipidemia. Atherosclerosis. 214:209-214.
Objective: α-Linolenic acid (ALA), the vegetable n-3fatty acid, appears to have antiatherosclerotic prop- erties akin to those of marine n-3 fatty acids. A prior study in a US population with low fish intake showed an inverse association between ALA intake and carotid plaque. We examined the association between the ALA status and advanced carotid and femoral atherosclerosis in subjects at high cardiovascular disease risk from Spain, a country with low coronary heart disease (CHD) rates and high fish consumption. Methods: Cross-sectional study of 211 patients with primary dyslipidemia, with determination of fatty acid composition of serum phosphatidylcholine by gas chromatography and plaque outcomes (frequency, number, maximum height and sum of plaque heights) in carotid and femoral arteries by sonography. Results: In multivariate regression analyses after adjusting for age, gender, lipid genotype, BMI, smoking, hypertension, diabetes mellitus, APOE4 genotype, prior statin treatment, and serum proportions of other unsaturated fatty acids known to relate to atherosclerosis, the proportion of ALA showed an inverse association with the risk of carotid plaque (OR [95%CI] 0.66 [0.44–0.91]) and concomitant carotid and femoral artery plaque (0.57 [0.38–0.86]). Conclusion: The inverse relationship between ALA in serum phosphatidylcholine and plaque burden in carotid and femoral arteries supports its antiatherosclerotic effect independently of fish-derived n-3 fatty acids. However, whether ALA enrichment in phospholipids is beneficial per se or is a surrogate of the consumption of bioactive compounds in parent foods deserves further research.
McKay, D.L., C.-Y. O. Chen, K.-J. Yeum, N.R. Matthan, A.H. Lichtenstein, J.B. Blumberg, 2010. Chronic and acute effects of walnuts on antioxidant capacity and nutritional status in humans: a randomized, cross-over pilot study. Nutrition Journal. 9:21-30.
Background: Compared with other common plant foods, walnuts (Juglans regia) are consistently ranked among the highest in antioxidant capacity. In vitro, walnut polyphenols inhibit plasma and LDL oxidation, while in animal models they lower biomarkers of oxidative stress and raise antioxidant capacity. A limited number of human feeding trials indicate that walnuts improve some measures of antioxidant status, but not others. Methods: A 19 wk, randomized crossover trial was conducted in 21 generally healthy men and postmenopausal women ≥50 y to study the dose-response effects of walnut intake on biomarkers of antioxidant activity, oxidative stress, and nutrient status. Subjects were randomized to receive either 21 or 42 g raw walnuts/d during each 6 wk intervention phase with a 6 wk washout between phases. Subjects were instructed to consume their usual diet, but refrain from eating any other tree nuts, seeds, peanuts, or ellagitannin-rich foods during the entire study, and other polyphenol-rich foods for 2 d prior to each study visit. Results: Compared to baseline levels, red blood cell (RBC) linoleic acid and plasma pyridoxal phosphate (PLP) were significantly higher after 6 wk with 42 g/d walnuts (P < 0.05 for both). Overall, changes in plasma total thiols, and other antioxidant biomarkers, were not significant with either walnut dose. However, when compared to fasting levels, plasma total thiols were elevated within 1 h of walnut consumption with both doses during the baseline and end visits for each intervention phase (P < 0.05 for all). Despite the observed increase in RBC linoleic and linolenic acids associated with walnut consumption, this substrate for lipid peroxidation only minimally affected malondialdehyde (MDA) and antioxidant capacity. The proportional changes in MDA and Oxygen Radical Absorbance Capacity (ORAC) were consistent with a dose-response effect, although no significant within- or between-group differences were observed for these measures. Conclusions: Walnut consumption did not significantly change the plasma antioxidant capacity of healthy, well-nourished older adults in this pilot study. However, improvements in linoleic acid and pyridoxal phosphate were observed with chronic consumption, while total plasma thiols were enhanced acutely. Future studies investigating the antioxidant effects of walnuts in humans are warranted, but should include either a larger sample size or a controlled feeding intervention.
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.
