本帖最後由 lsc0019 於 2009-4-15 00:22 編輯
作者：Laurie Barclay, MD
出處：WebMD醫學新聞
March 25, 2009 — 根據發表於3/4月號家庭醫學年鑑的一篇後設分析，規律使用可溶性纖維適用於不論有沒有高膽固醇症之成人的飲食。
康乃迪克大學藥學院的Ripple Talati藥學博士等人寫道，雖然燕麥的抗高血脂效果已經廣為研究，但是有關大麥的研究卻較少，研究發現顯示其對膽固醇的效果相當不一樣。即使有多個臨床試驗探究大麥之乙型葡聚糖對總膽固醇、LDL[低密度脂蛋白]膽固醇、高密度脂蛋白(HDL)膽固醇、三酸甘油脂的效果，卻未曾有過對這些效果的後設分析 ；因此，我們進行大麥隨機控制試驗的後設分析，以更清楚它對各種脂質參數的影響。
回顧者從最早有資料時到2008年1月止，進行系統性文獻搜尋。納入後設分析之規範為大麥隨機控制試驗且有關一種以上脂質結果測量之報告。以DerSimonian暨Laird氏隨機效應模式衡量平均差異與其95%信心區間[CI]，以I2 statistic評估統計異質性。使用漏斗散佈圖目視檢查、Egger氏加權回歸統計、整理與填充方法評估發表偏差。
有八篇評估大麥降脂質效果的試驗符合納入規範；研究期間從4到12週，共包括391名病患。使用大麥與顯著降低總膽固醇(加權均術差為 –13.38 mg/dL；95% CI為 –18.46 到 –8.31 mg/dL)、LDL膽固醇(加權均術差為–10.02 mg/dL；95% CI為 –14.03到–6.00 mg/dL)以及三酸甘油脂(加權均術差為–11.83 mg/dL；95% CI為–20.12 到 –3.55 mg/dL)有關。不過，對HDL膽固醇值沒有任何顯著影響(P = .07)。
研究作者寫道，大麥衍生的乙型葡聚糖對總膽固醇、LDL膽固醇、三酸甘油脂顯示有效，對HDL膽固醇則沒有。根據現有資料，大麥耐受良好，胃腸脹氣以及腹部不適是最常被報告的不良反應，但是其他少見的不良反應並無有力證據支持。
這個後設分析的限制包括，同時納入了交叉型與平行型研究，可能有發表偏差，無法評估大麥的可能傷害等。
回顧作者結論表示，我們的研究結果支持於不論有沒有高膽固醇症成人的飲食中規律使用可溶性纖維。大麥與其他可溶性纖維來源，燕麥、洋車前子、果膠以及華膠等都可以健康食用。健康執業人員可安心建議病患食用大麥乙型葡聚糖，以幫助降低總膽固醇和LDL膽固醇，如同NCEP指引所建議的。
研究作者宣告沒有相關財務關係。
Dietary Soluble Fiber May Be Beneficial for Adults With and Without Hypercholesterolemia
By Laurie Barclay, MD
Medscape Medical News
March 25, 2009 — The routine use of soluble fibers may be indicated in the diets of adult patients with and without hypercholesterolemia, according to the results of a meta-analysis reported in the March/April issue of the Annals of Family Medicine.
"Although the antihyperlipidemic effects of oats have been extensively studied, there are fewer barley studies, and findings have shown more apparent inconsistency in cholesterol effects," write Ripple Talati, PharmD, from University of Connecticut School of Pharmacy in Storrs, and colleagues. "Even though several clinical trials have investigated the impact of barley β-glucan on total cholesterol, LDL [low-density lipoprotein] cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides, a meta-analysis assessing these effects has not been published. We therefore sought to perform a meta-analysis of randomized controlled trials of barley to better characterize its effect on various lipid parameters."
The reviewers performed a systematic search of the literature from the earliest possible date through January 2008. Inclusion criteria for the meta-analysis were randomized controlled trials of barley reporting efficacy data for 1 or more lipid outcome measures. Weighted mean difference and its 95% confidence interval (CI) were determined by a DerSimonian and Laird random-effects model, and statistical heterogeneity was evaluated with the I2 statistic. Publication bias was assessed with visual inspection of funnel plots, Egger's weighted regression statistics, and the trim-and-fill method.
Eight trials evaluating the lipid-reducing effects of barley met inclusion criteria; these were of 4 to 12 weeks' duration and enrolled a total of 391 patients. The use of barley was associated with significant reduction in levels of total cholesterol (weighted mean difference, –13.38 mg/dL; 95% CI, –18.46 to –8.31 mg/dL), LDL cholesterol (weighted mean difference, –10.02 mg/dL; 95% CI, –14.03 to –6.00 mg/dL), and triglycerides (weighted mean difference, –11.83 mg/dL; 95% CI, –20.12 to –3.55 mg/dL). However, there did not appear to be any significant effect on HDL cholesterol levels (P = .07).
"Barley-derived β-glucan appears to beneficially affect total cholesterol, LDL-cholesterol, and triglycerides, but not HDL-cholesterol," the study authors write. "Based upon available data, barley appears to be well tolerated, with flatulence and abdominal discomfort being reported as the most common adverse effects, but there is not adequate power to look for other less common adverse effects."
Limitations of this meta-analysis are inclusion of crossover and parallel studies, potential for publication bias, and inability to evaluate the potential for harms with barley.
"The results of our study support the routine use of soluble fibers in the diets of adult patients with and without hypercholesterolemia," the review authors conclude. "Barley adds another source of soluble fibers, in addition to oats, psyllium, pectin, and guar gum that patients can consume as part of a healthy diet....Health practitioners should feel comfortable recommending barley β-glucan to their patients to help reduce total cholesterol and LDL cholesterol concentrations as recommended by the NCEP guidelines."
The study authors have disclosed no relevant financial relationships.
Ann Fam Med. 2009;7:157-163. |
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