Austria J Alejandro, Richard Melanie N, Chahine Mirna N, Edel Andrea L, Malcolmson Linda J, Dupasquier Chantal M C, Pierce Grant N
Cell Biology Laboratory, St Boniface Hospital Research Centre, Winnipeg, Manitoba, R2H 2A6, Canada.
J Am Coll Nutr. 2008 Apr;27(2):214-21. doi: 10.1080/07315724.2008.10719693.
Dietary flaxseed may have significant health-related benefits due to its high content of the omega-3 fatty acid, alpha-linolenic acid (ALA). However, before extensive work can be undertaken in clinical populations to determine its efficacy, basic information on ALA bioavailability from flaxseed and the physiological effects of its ingestion need to be examined.
The purpose of this study, therefore, was to determine the bioavailability of ALA when the flaxseed was ingested in the form of whole seed, milled seed or as flaxseed oil.
The flaxseed components (30 g of seed or 6 g of ALA in the oil) were baked into muffins for delivery over a 3 month test period in healthy male and female subjects.
Flaxseed ingestion over a 1 month period resulted in significant (P = 0.005) increases in plasma ALA levels in the flaxseed oil and the milled flaxseed supplemented groups. The former group had significantly (P = 0.004) higher ALA levels than the milled flaxseed group. The subjects supplemented with whole flaxseed did not achieve a significant (P > 0.05) increase in plasma ALA levels. An additional two months of flaxseed ingestion did not achieve significantly higher levels of plasma ALA in any of the groups. However, no significant increase was detected in plasma eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) levels in any of the flax-fed groups. There were no changes in plasma cholesterol or triglycerides or in platelet aggregation at any time point in any of the groups. Subjects in all of the groups exhibited some symptoms of gastro-intestinal discomfort during the early stages of the study but these disappeared in the oil and milled seed groups. However, compliance was a problem in the whole flaxseed group.
In summary, ingestion of flax oil and milled flaxseed delivered significant levels of ALA to the plasma whereas whole flaxseed did not. Whole seed and oil preparations induced adverse gastrointestinal effects within 4 weeks and these were severe enough to induce the withdrawal of some subjects from these two groups. No one withdrew from the group that ingested milled flaxseed and, therefore, may represent a good form of flaxseed to avoid serious side-effects and still provide significant increases in ALA to the body.
膳食亚麻籽可能因其富含ω-3脂肪酸α-亚麻酸（ALA）而具有显著的健康益处。然而，在临床人群中开展大量工作以确定其功效之前，需要研究亚麻籽中ALA的生物利用度以及摄入亚麻籽的生理效应等基础信息。
因此，本研究的目的是确定以整粒种子、磨碎种子或亚麻籽油形式摄入亚麻籽时ALA的生物利用度。
将亚麻籽成分（30克种子或油中6克ALA）烘焙成松饼，在3个月的试验期内供健康男性和女性受试者食用。
在1个月的时间内摄入亚麻籽后，亚麻籽油组和磨碎亚麻籽补充组的血浆ALA水平显著升高（P = 0.005）。前一组的ALA水平显著高于磨碎亚麻籽组（P = 0.004）。补充整粒亚麻籽的受试者血浆ALA水平未显著升高（P > 0.05）。再额外摄入两个月亚麻籽后，任何一组的血浆ALA水平均未显著升高。然而，在任何亚麻籽喂养组中，血浆二十碳五烯酸（EPA）或二十二碳六烯酸（DHA）水平均未检测到显著升高。在任何组的任何时间点，血浆胆固醇、甘油三酯或血小板聚集均无变化。在研究初期，所有组的受试者均出现了一些胃肠道不适症状，但在油组和磨碎种子组中这些症状消失了。然而，整粒亚麻籽组存在依从性问题。
总之，摄入亚麻籽油和磨碎的亚麻籽可使血浆中ALA达到显著水平，而整粒亚麻籽则不能。整粒种子和油制剂在4周内引发了不良胃肠道效应，严重到足以导致一些受试者退出这两组。没有人从摄入磨碎亚麻籽的组中退出，因此，磨碎亚麻籽可能是一种既能避免严重副作用又能使体内ALA显著增加的良好亚麻籽形式。
