根据一项研究显示，适量吃一些坚果类食品，由于其中富含的营养及天然抗氧化剂成分，可以有效的降低患上心血管疾病及癌症的风险。
据国外媒体报道，坚果类食物中特别富含一种被称为伽马维生素E(gamma-tocopherol)的抗氧化剂成分，该项研究显示人在食用诸如山核桃等食品后的8小时内这些成分都会发生影响。研究人员对16位男性和女性志愿者进行了分析，他们分别被要求食用山核桃，核桃混合饮品和普通食物，结果发现核桃类食品对于减少人体血液中的“坏”胆固醇有着积极的影响。
领导这项研究的是加利福尼亚洛玛连达大学(Loma Linda University)的艾拉-(Ella Haddad)。艾拉表示，这些抗氧化剂容易被人体所吸收，并且具有对一些疾病的预防作用。这种保护能够防止比如癌症和心血管疾病的发生。目前该项研究的结果已经发表在了美国《营养学期刊》中。
最新的研究证据显示，坚果类食物能够促进健康。核桃帮助降低胆固醇，杏仁和富含硒的巴西坚果能够预防某些癌症。艾拉表示，过去的研究表明山核桃中富含抗氧化素，而这项研究显示了这些抗氧化剂的确能较容易被人体所吸收，并且能通过母乳喂养来对婴儿产生积极作用。
Pecans Acutely Increase Plasma Postprandial Antioxidant Capacity and Catechins and Decrease LDL Oxidation in Humans1,2,3
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.
