Department of Nutrition, School of Public Health, Loma Linda University, Loma Linda, CA 92350, USA.
J Nutr. 2011 Jan;141(1):56-62. doi: 10.3945/jn.110.121269. Epub 2010 Nov 24.
Bioactive constituents of pecan nuts such as γ-tocopherol and flavan-3-ol monomers show antioxidant properties in vitro, but bioavailability in humans is not known. We examined postprandial changes in plasma oxygen radical absorbance capacity (ORAC) and in concentrations of tocopherols, catechins, oxidized LDL, and malondialdehyde (MDA) in response to pecan test meals. Sixteen healthy men and women (23-44 y, BMI 22.7 ± 3.4) were randomly assigned to 3 sequences of test meals composed of whole pecans, blended pecans, or an isocaloric meal of equivalent macronutrient composition but formulated of refined ingredients in a crossover design with a 1-wk washout period between treatments. Blood was sampled at baseline and at intervals up to 24 h postingestion. Following the whole and blended pecan test meals, plasma concentrations of γ-tocopherols doubled at 8 h (P < 0.001) and hydrophilic- and lipophilic-ORAC increased 12 and 10% at 2 h, respectively. Post whole pecan consumption, oxidized LDL decreased 30, 33, and 26% at 2, 3, and 8 h, respectively (P < 0.05), and epigallocatechin-3-gallate concentrations at 1 h (mean ± SEM; 95.1 ± 30.6 nmol/L) and 2 h (116.3 ± 80.5 nmol/L) were higher than at baseline (0 h) and after the control test meal at 1 h (P < 0.05). The postprandial molar ratio of MDA:triglycerides decreased by 37, 36, and 40% at 3, 5, and 8 h, respectively (P < 0.05), only when whole and blended pecan data were pooled. These results show that bioactive constituent of pecans are absorbable and contribute to postprandial antioxidant defenses.
山核桃中的生物活性成分,如γ-生育酚和黄烷-3-醇单体,在体外显示出抗氧化特性,但人体的生物利用度尚不清楚。我们研究了山核桃测试餐对血浆氧自由基吸收能力(ORAC)和生育酚、儿茶素、氧化 LDL 和丙二醛(MDA)浓度的餐后变化。16 名健康男性和女性(23-44 岁,BMI 22.7±3.4)被随机分配到 3 个测试餐序列,分别由完整山核桃、混合山核桃或由精制成分制成的等宏量营养素组成的热量相同的膳食组成,采用交叉设计,每种处理之间有 1 周的洗脱期。在基线和摄入后 24 小时内的时间间隔内采集血液样本。在食用完整和混合山核桃餐后,血浆γ-生育酚浓度在 8 小时时增加了一倍(P<0.001),亲水性和疏水性 ORAC 在 2 小时时分别增加了 12%和 10%。在食用完整山核桃后,氧化 LDL 在 2、3 和 8 小时时分别降低了 30%、33%和 26%(P<0.05),表没食子儿茶素-3-没食子酸酯在 1 小时(平均值±SEM;95.1±30.6 nmol/L)和 2 小时(116.3±80.5 nmol/L)时的浓度高于基线(0 小时)和 1 小时时的对照测试餐(P<0.05)。丙二醛:甘油三酯的餐后摩尔比在 3、5 和 8 小时时分别降低了 37%、36%和 40%(P<0.05),仅当将完整和混合山核桃的数据合并时才会出现这种情况。这些结果表明,山核桃中的生物活性成分是可吸收的,并有助于餐后抗氧化防御。