Borkowski, K., S.J. Yim, R.R. Holt, R.M. Hackman, C.L. Keen, J.W. Newman, G.C. Shearer, 2019. Walnuts change lipoprotein composition suppressing TNFa-stimulated cytokine production by diabetic adipocyte. J Nutr Biochem. 68:51-58.
Walnut consumption can provide both vascular and metabolic health benefits, and walnut-induced changes in lipoprotein particle chemical payloads may be responsible for these health benefits. To explore this possibility with a focus on metabolic health, this study investigated the impact of walnut consumption on lipoprotein lipid composition and changes in LDL anti-inflammatory properties, as reported by inflamed adipocyte. Hypercholesterolemic, postmenopausal females were treated with 40 g/day (i.e., 1.6 servings/day; n=15) of walnuts for 4 weeks. Fatty acids and their oxygenated metabolites, i.e., oxylipins, were quantified in isolated lipoproteins. Human primary adipocytes were exposed to LDL and TNFα-stimulated adipokine production was measured. Walnut treatment elevated α-linolenic acid and its epoxides in all lipoproteins and depleted mid-chain alcohols in VLDL and LDL, but not HDL. Walnuts also reduced TNFα-induced diabetic adipocyte production of IL-6 (−48%, P=.0006) and IL-8 (−30%, P=.01), changes inversely correlated with levels of α-linolenic acid-derived epoxides but not α-linolenic acid itself. In conclusion, modest walnut consumption can alter lipoprotein lipid profiles and enhance their ability to inhibit TNFα-dependent pro-inflammatory responses in human diabetic primary adipocytes. Moreover, this study suggests the oxylipins, rather than the parent fatty acids, mediate LDL action of adipocytes.
Chen, C.-Y.O., P.E. Milbury, J.B. Blumberg, 2019. Polyphenols in almond skins produced during almond blanching process modulate plasma biomarkers of oxidative stress in healthy humans. Antioxidants. 8, 95. doi: https://www.mdpi.com/2076-3921/8/4/95/pdf
Almond skins are a waste byproduct of blanched almond production. Polyphenols extracted from almond skins possess antioxidant activities in vitro and in vivo. Thus, we examined the pharmacokinetic profile of almond skin polyphenols (ASP) and their effect on measures of oxidative stress. In a randomized crossover trial, seven adults consumed two acute ASP doses (225 mg (low, L) or 450 mg (high, H) total phenols) in skim milk or milk alone. Plasma flavonoids, glutathione peroxidase (GPx), glutathione (GSH), oxidized GSH (GSSG), and resistance of low-density lipoprotein (LDL) to oxidation were measured over 10 h. The H dose increased catechin and naringenin in plasma, with maximum concentrations of 44.3 and 19.3 ng/mL, respectively. The GSH/GSSG ratio at 3 h after the H doses was 212% of the baseline value, as compared to 82% after milk (p = 0.003). Both ASP doses upregulated GPx activity by 26–35% from the baseline at 15, 30, 45, and 120 min after consumption. The in vitro addition of α-tocopherol extended the lag time of LDL oxidation at 3 h after L and H consumption by 144.7% and 165.2% of that at 0 h compared to no change after milk (p≤0.05). In conclusion, ASP are bioavailable and modulate GSH status, GPx activity, and the resistance of LDL to oxidation.
Kellett, M.E., P. Greenspan, Y. Gong, R.B. Pegg, 2019. Cellular evaluation of the antioxidant activity of U.S. pecans [Carya illinoinensis (Wangenh.) K. Koch]. Food Chem. 293:511-519. https://doi.org/10.1016/j.foodchem.2019.04.103
Clinical trials show an inverse relationship between the consumption of antioxidant-rich tree nuts and the development of chronic diseases. This study examined antioxidant efficacy of U.S. pecans using a modified cellular antioxidant activity (CAA) assay with comparisons to data from in vitro antioxidant assays (hydrophilic-oxygen radical absorbance capacity {H-ORACFL} and ferric reducing antioxidant power {FRAP}). Crude phenolic extracts from both raw and roasted pecans were analyzed. In the CAA assay, pecan phenolics were taken up by human colorectal adenocarcinoma (Caco-2) cells and bestowed CAA, determined by monitoring the fluorescence of 2′,7′-dichlorofluorescein. Phenolics (25-100 μg/mL) demonstrated a reduction in fluorescence by 37-69% for raw and 26-68% for roasted pecans. The primary active phenolic constituents were determined by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) to be epi(catechin) dimers and trimers. These oligomeric procyanidins, ranging in size from 560 to 840 g/mol appear to be small enough for cellular uptake, showing pecans are an effective antioxidant in biological systems, regardless of roasting.
G.B.S. Duarte, B.Z. Reis, M.M. Rogero, E. Vargas-Mendez, F.B. Júnior, C. Cercato, S.M.F. Cozzolino, 2019. Consumption of Brazil nuts with high selenium levels increased inflammation biomarkers in obese women: A randomized controlled trial. Nutrition. 63-64:162-168.
Objective: Increased inflammatory response is an important factor in the pathophysiology of obesity. The mineral selenium (Se), of which one of the main food sources is the Brazil nut, has important antioxidant and anti-inflammatory functions through the action of selenoproteins. Thus, the evaluation of the influence of this micronutrient in this context is of great relevance. The aim of this study was to evaluate the effects of Brazil nut intake with high Se concentrations on inflammatory biomarkers and its relation to Se status in obese women. Methods:A randomized controlled clinical trial was carried out with 55 women recruited at Clinical Hospital in São Paulo, Brazil. Patients were randomly assigned to either the Brazil nut group (BN) or the control group (CO) and followed up for 2 mo. The BN group consumed 1 unit/d of Brazil nuts (∼ 1261 μg/Se); the CO group did not receive any intervention. At baseline and after 2 mo, analysis of biochemical parameters related to Se status, oxidative stress, and inflammatory biomarkers were performed. Results:At baseline, both groups did not present Se deficiency. In the BN group, a significant increase (P < 0.05) in all Se biomarkers and in gene expression of several proinflammatory parameters (interleukin-6, tumor necrosis factor-α, and Toll-like receptors 2 and 4) were observed after the intervention period. No changes were observed for the CO group. Conclusion:Although there were no changes in plasma inflammatory biomarkers levels, a significant increase in gene expression may be an indication of a proinflammatory stimulus in obesity, induced by the consumption of Brazil nuts with high Se levels.
