碳水化合物質量與人類健康：系列綜述

Carbohydrate quality and human health: a series of systematic reviews and meta-analyses

• Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet 2019.
• Correspondence to:Prof Jim Mann, Department of Medicine, University of Otago, Dunedin, Otago 9016, New Zealand jim.mann@otago.ac.nz

Background 背景

Previous systematic reviews and meta-analyses explaining the relationship between carbohydrate quality and health have usually examined a single marker and a limited number of clinical outcomes. We aimed to more precisely quantify the predictive potential of several markers, to determine which markers are most useful, and to establish an evidence base for quantitative recommendations for intakes of dietary fibre.

以往解釋碳水化合物質量和健康之間的關係的系統回顧和薈萃分析，通常只測試了一種標記物並且臨床結果有限。我們的目標是更精確地量化幾種標記物的預測潛力，以確定哪些標記物最有用，並為膳食纖維攝入量的定量建議建立循證基礎。

Methods 方法

We did a series of systematic reviews and meta-analyses of prospective studies published from database inception to April 30, 2017, and randomised controlled trials published from database inception to Feb 28, 2018, which reported on indicators of carbohydrate quality and non-communicable disease incidence, mortality, and risk factors.

我們對從資料庫建立至2017年4月30日期間發表的前瞻性研究，和從資料庫建立到2018年2月28日期間發表的隨機對照試驗進行了一系列系統性回顧和薈萃分析，這些試驗報告了碳水化合物質量和非傳染性疾病發病率、死亡率以及危險因素的指標。

Studies were identified by searches in PubMed, Ovid MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials, and by hand searching of previous publications. We excluded prospective studies and trials reporting on participants with a chronic disease, and weight loss trials or trials involving supplements. Searches, data extraction, and bias assessment were duplicated independently.

我們通過檢索PubMed、Ovid MEDLINE、Embase和the Cochrane Central Register of Controlled Trials，以及翻閱檢索以前的出版物，確定了研究。我們排除了對患有慢性疾病的參與者的前瞻性研究和試驗報告，以及減肥試驗或包含有補充營養的試驗。我們對這些研究分別進行重複搜索、數據提取和偏差評估。

Robustness of pooled estimates from random-effects models was considered with sensitivity analyses, meta-regression, dose-response testing, and subgroup analyses. The GRADE approach was used to assess quality of evidence.

通過敏感性分析、元回歸、劑量反應測試和亞組分析，考量了隨機效應模型的合併估計的穩健性。採用GRADE法來評價證據質量。

Findings 發現

Just under 135 million person-years of data from 185 prospective studies and 58 clinical trials with 4635 adult participants were included in the analyses. Observational data suggest a 15–30% decrease in all-cause and cardiovascular related mortality, and incidence of coronary heart disease, stroke incidence and mortality, type 2 diabetes, and colorectal cancer when comparing the highest dietary fibre consumers with the lowest consumers. Clinical trials show significantly lower bodyweight, systolic blood pressure, and total cholesterol when comparing higher with lower intakes of dietary fibre.

來自185項前瞻性研究和58項包括4635名成年受試者的臨床試驗的共計近1.35億人年的數據被納入分析。觀察數據顯示，與膳食纖維攝入量最高的人群相比，膳食纖維攝入量最低的人群的全因和心血管相關死亡率、冠心病發病率、中風發病率和死亡率、2型糖尿病和結腸直腸癌發病率下降了15-30%。臨床試驗表明，與膳食纖維攝入量較低的人相比，食用纖維攝入量較高的人體重、收縮壓和總膽固醇明顯較低。

Risk reduction associated with a range of critical outcomes was greatest when daily intake of dietary fibre was between 25 g and 29 g. Dose-response curves suggested that higher intakes of dietary fibre could confer even greater benefit to protect against cardiovascular diseases, type 2 diabetes, and colorectal and breast cancer. Similar findings for whole grain intake were observed. Smaller or no risk reductions were found with the observational data when comparing the effects of diets characterised by low rather than higher glycaemic index or load.

當每日膳食纖維攝入量在25克至29克之間時，與一系列重要疾病相關的風險降低幅度最大。劑量-反應曲線表明，攝入更多膳食纖維，對預防心血管疾病、2型糖尿病、結腸直腸癌和乳腺癌有更大的益處。在全穀物攝入量方面也觀察到類似的結果。在比較以低血糖指數而非高血糖指數或負荷為特徵的飲食的效果時，觀察數據顯示，其降低的風險較小或沒有降低。

The certainty of evidence for relationships between carbohydrate quality and critical outcomes was graded as moderate for dietary fibre, low to moderate for whole grains, and low to very low for dietary glycaemic index and glycaemic load. Data relating to other dietary exposures are scarce.

碳水化合物質量和重要結果（疾病相關）之間關係的確切程度，被劃分為膳食纖維適度、全穀物低至中度、膳食血糖指數和血糖負荷低至極低。其他飲食相關暴露的數據很少。

Interpretation 解釋

Findings from prospective studies and clinical trials associated with relatively high intakes of dietary fibre and whole grains were complementary, and striking dose-response evidence indicates that the relationships to several non-communicable diseases could be causal. Implementation of recommendations to increase dietary fibre intake and to replace refined grains with whole grains is expected to benefit human health.

膳食纖維和全穀物的相對高攝入量相關的前瞻性研究和臨床試驗的結果也相輔相成，並且明顯的劑量反應證據表明，該攝入量與若干非傳染性疾病可能是因果關係。遵循增加膳食纖維攝入量和用全穀物代替精製穀物的建議將有益於人類健康。

A major strength of the study was the ability to examine key indicators of carbohydrate quality in relation to a range of non-communicable disease outcomes from cohort studies and randomised trials in a single study. Our findings are limited to risk reduction in the population at large rather than those with chronic disease.

這項研究的一個主要亮點在於，它能夠從一項研究中對隊列研究和隨機試驗中一系列與非傳染性疾病結果相關的碳水化合物質量的關鍵指標進行檢測。我們的發現僅限於降低總體人群的發病風險，而非慢性病患者。

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