膳食纖維與糖尿病風險下降有關

作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　August 10, 2009 — 根據一項於7月23日發表在糖尿病照護期刊的前瞻性研究結果，膳食纖維與第二型糖尿病風險下降有關，這可能部分由發炎指標與肝臟脂肪沉積解釋。
　　
　　英國倫敦大學醫學院S. Goya Wannamethee博士與同事們寫到，許多前瞻性世代研究觀察到膳食纖維對於第二型糖尿病風險有保護作用。然而，不是所有研究都觀察到這個現象，且膳食纖維可能對於糖尿病有益的機轉仍然不明。許多研究已經證實膳食纖維與發炎指標、胰島素敏感性、肝臟功能、以及與糖尿病發展之間有反向關係。
　　
　　這項研究的目標在於評估高齡男性病患，膳食纖維與第二型糖尿病風險之間的關係，以及肝臟及發炎指標的角色。這項研究包括3,428位非糖尿病男性，年齡介於60至79歲，這些群眾都收納在英國地區心臟研究（BRHS）中。在7年的後續追蹤，總共發生162件第二型糖尿病病例。
　　
　　校正總能量攝取與潛在的影響變項後，總膳食纖維最低的四分位數（每天低於20 g）與糖尿病風險增加有關（相對風險[RR]為1.47；95%信賴區間[CI]為1.03-2.11）。低穀物與低蔬菜/水果纖維攝取都與風險增加有關。
　　
　　膳食纖維反向地與發炎標記C反應蛋白（CRP）及介白素-6（IL-6），還有組織胞漿素原活化素（t-PA）以及麩氨酸轉移酵素（GGT）有關。在校正這些指標後，低膳食纖維與糖尿病風險增加程度下降（RR為1.28；95% CI為0.89-1.86）。
　　
　　作者們寫到，膳食纖維與糖尿病風險下降有關可能可以部分由發炎指標、肝臟脂肪沉積解釋。我們無法建立膳食纖維與肝臟功能及發炎過程之間關聯的本質。
　　
　　這項研究的限制包括收納主要是白種人、歐洲裔、男性族群，限制了這些發現的應用性。未來的研究需要針對女性與其他人種進行。
　　
　　歐洲心臟基金會研究團隊贊助這項研究。BRHS也接受來自英國糖尿病學會的贊助。試驗作者們表示沒有相關資金上的往來。

Dietary Fiber Is Linked to Lower Diabetes Risk

By Laurie Barclay, MD
Medscape Medical News

August 10, 2009 —- Dietary fiber is linked to a reduced risk for type 2 diabetes, which may be partly explained by inflammatory markers and hepatic fat deposition, according to the results of a prospective study reported ahead of print in the July 23 issue of Diabetes Care.

"Several prospective cohort studies have observed a protective effect of dietary fiber on risk of type 2 diabetes," write S. Goya Wannamethee, PhD, from University College Medical School in London, United Kingdom, and colleagues. "However, this has not been observed in all studies and the biological mechanisms by which dietary fiber may be beneficial for diabetes are unclear. Several studies have shown inverse associations between dietary fiber and markers of inflammation, insulin sensitivity and hepatic function, factors which have been linked to the development of diabetes in other studies."

The goal of this study was to evaluate the association between dietary fiber and the risk for type 2 diabetes in older men, as well as the role of hepatic and inflammatory markers. The study cohort consisted of 3428 nondiabetic men aged 60 to 79 years who were originally enrolled in the British Regional Heart Study (BRHS). During a 7-year follow-up, there were 162 incident cases of type 2 diabetes.

After adjustment for total energy intake and potential confounding variables, the lowest quartile of total dietary fiber (? 20 g/day) was associated with an increased risk for diabetes (relative risk [RR], 1.47; 95% confidence interval [CI], 1.03 - 2.11). Low cereal and low vegetable/fruit fiber intake were each separately associated with increased risk.

Dietary fiber was inversely associated with the inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6), as well as with tissue plasminogen activator (t-PA) and gamma glutamyl transferase (GGT). After adjusting for these markers, the increased risk for diabetes seen with low dietary fiber was attenuated (RR, 1.28; 95% CI, 0.89 - 1.86).

"Dietary fiber is associated with reduced diabetes risk which may be partly explained by inflammatory markers and hepatic fat deposition," the study authors write. "We can not establish the nature of the association between fiber intake and hepatic function and the inflammatory process."

Limitations of this study include a predominantly white, European, male population, limiting generalizability of the findings. Further studies are required in women and in other ethnic groups.

The British Heart Foundation Research Group supported this study. The BRHS also received support from Diabetes UK. The study authors have disclosed no relevant financial relationships.

Diabetes Care. Published online July 23, 2009.