Hahn School of Nursing and Health Sciences, University of San Diego, CA, USA.
Department of Biostatistics, Gillings School of Global Public Health and School of Nursing, University of North Carolina at Chapel Hill, NC, USA.
Clin Nutr. 2015 Apr;34(2):212-8. doi: 10.1016/j.clnu.2014.03.003. Epub 2014 Mar 14.
BACKGROUND & AIMS: Several studies have demonstrated that vegetarians and vegans have much lower plasma concentrations of omega-3 fatty acids (i.e., docosahexaenoic and eicosapentaenoic acids) when compared to those who eat fish. The purposes of this study were 1) to define the age and/or sex-specific docosahexaenoic plus eicosapentaenoic acids levels in red blood cell membranes (expressed as a percent of total fatty acids; hereafter the omega-3 index) in long-term vegans, and 2) to determine the effects of a vegetarian omega-3 supplement (254 mg docosahexaenoic plus eicosapentaenoic acids/day for 4 months) on the omega-3 index.
A sample (n = 165) of vegans was recruited, and their omega-3 index was determined using a dried blood spot methodology. A subset of 46 subjects with a baseline omega-3 index of <4% was given a vegetarian omega-3 supplement for 4 months and then retested.
The mean ± SD omega-3 index was 3.7 ± 1.0% which was similar to that of a cohort of omnivores (deployed US soldiers) from a recently-reported study. Among the vegan cohort, the index was significantly higher in females than males (3.9 ± 1.0% vs. 3.5 ± 1.0%; p = 0.026) and was directly related to age (p for trend = 0.009). The omega-3 index increased from 3.1 ± 0.6% to 4.8 ± 0.8% (p = 0.009) in the supplementation study.
We conclude that vegans have low baseline omega-3 levels, but not lower than omnivores who also consume very little docosahexaenoic and eicosapentaenoic acids. The vegans responded robustly to a relatively low dose of a vegetarian omega-3 supplement.
多项研究表明，素食者和严格素食者的血液中 ω-3 脂肪酸（即二十二碳六烯酸和二十碳五烯酸）浓度明显低于吃鱼的人。本研究的目的是：1）定义长期素食者的红细胞膜中二十二碳六烯酸加二十碳五烯酸的水平（以总脂肪酸的百分比表示；以下简称 ω-3 指数），并按年龄和/或性别进行区分；2）确定素食者 ω-3 补充剂（每天 254mg 二十二碳六烯酸加二十碳五烯酸，持续 4 个月）对 ω-3 指数的影响。
招募了一组（n=165）素食者，使用干血斑法测定其 ω-3 指数。46 名基线 ω-3 指数＜4%的受试者接受了 4 个月的素食者 ω-3 补充剂治疗，然后进行了复测。
平均±标准差 ω-3 指数为 3.7±1.0%，与最近一项研究中一组杂食者（美国现役军人）的指数相似。在素食者队列中，女性的指数明显高于男性（3.9±1.0%比 3.5±1.0%；p=0.026），且与年龄呈正相关（趋势 p 值=0.009）。补充研究中，ω-3 指数从 3.1±0.6%增加到 4.8±0.8%（p=0.009）。
我们的结论是，素食者的 ω-3 基线水平较低，但并不低于很少摄入二十二碳六烯酸和二十碳五烯酸的杂食者。素食者对相对较低剂量的素食者 ω-3 补充剂反应强烈。
