Khalesi Saman, Irwin Christopher, Schubert Matt
School of Medicine and
School of Allied Health Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.
J Nutr. 2015 Apr;145(4):758-65. doi: 10.3945/jn.114.205302. Epub 2015 Mar 4.
High blood pressure is a major health burden positively associated with the risk of cardiovascular disease and other chronic diseases. Flaxseed is a rich dietary source of α-linolenic acid, lignans, and fiber, with a number of positive health benefits on blood pressure.
The purpose of this study was to clarify the effect of flaxseed consumption on blood pressure. Further, the influence of baseline blood pressure, type of flaxseed supplementation, and duration of flaxseed supplementation on blood pressure was explored.
PubMed (MEDLINE), Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library (Central) were searched through July 2014 for studies in which humans supplemented their habitual diet with flaxseed or its extracts (i.e., oil, lignans, fiber) for ≥2 wk.
A total of 11 studies (14 trials) were included in the analysis. Random-effects meta-analyses were conducted for the mean difference in blood pressure. Results indicated that flaxseed supplementation reduced systolic blood pressure (-1.77 mm Hg; 95% CI: -3.45, -0.09 mm Hg; P = 0.04) and diastolic blood pressure (-1.58 mm Hg; 95% CI: -2.64, -0.52 mm Hg; P = 0.003). These results were not influenced by categorization of participants into higher baseline blood pressure (≥130 mm Hg). An improvement in diastolic blood pressure was observed in subgroup analysis for consuming whole flaxseed (-1.93 mm Hg; 95% CI: -3.65, -0.21 mm Hg; P < 0.05) and duration of consumption ≥12 wk (-2.17 mm Hg; 95% CI: -3.44, -0.89 mm Hg; P < 0.05).
The present meta-analysis suggests that consumption of flaxseed may lower blood pressure slightly. The beneficial potential of flaxseed to reduce blood pressure (especially diastolic blood pressure) may be greater when it is consumed as a whole seed and for a duration of >12 wk.
高血压是一种主要的健康负担，与心血管疾病及其他慢性病的风险呈正相关。亚麻籽是α-亚麻酸、木脂素和纤维的丰富膳食来源，对血压具有诸多积极的健康益处。
本研究旨在阐明食用亚麻籽对血压的影响。此外，还探讨了基线血压、亚麻籽补充剂类型以及亚麻籽补充持续时间对血压的影响。
检索了截至2014年7月的PubMed（医学文献数据库）、护理学与健康相关文献累积索引以及考克兰图书馆（核心库），查找人类在其日常饮食中补充亚麻籽或其提取物（即油、木脂素、纤维）≥2周的研究。
分析共纳入11项研究（14项试验）。对血压的平均差异进行了随机效应荟萃分析。结果表明，补充亚麻籽可降低收缩压（-1.77毫米汞柱；95%置信区间：-3.45，-0.09毫米汞柱；P = 0.04）和舒张压（-1.58毫米汞柱；95%置信区间：-2.64，-0.52毫米汞柱；P = 0.003）。这些结果不受将参与者分类为较高基线血压（≥130毫米汞柱）的影响。在食用整粒亚麻籽的亚组分析（-1.93毫米汞柱；95%置信区间：-3.65，-0.21毫米汞柱；P < 0.05）和食用持续时间≥12周的亚组分析（-2.17毫米汞柱；95%置信区间：-3.44，-0.89毫米汞柱；P < 0.05）中观察到舒张压有所改善。
本荟萃分析表明，食用亚麻籽可能会略微降低血压。当将亚麻籽作为整粒种子食用且持续时间>12周时，其降低血压（尤其是舒张压）的有益潜力可能更大。
