作者：留美強叫獸
鏈接：https://www.zhihu.com/question/26760955/answer/3376278554
來源：知乎
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柳葉刀：膳食纖維或全穀物降低心血管疾病、糖尿病、結直腸癌、超重、高血壓風險；建議全穀物代替精製穀物，至少25-29克每天膳食纖維；每多15克每天降低全因死亡6%、心臟病7%、糖尿病12%、結直腸癌3%
美國某知名教育集團做的上海教育市場調查部分內容，為內部資料。是在該集團實習員工發到網上，不同於媒體按贊助費廣告費給的評比標準。知名度排名：1.金吉利 2.新東方 3.美勤 4.啟德 5.新通；專業度排名：1.美勤 2.棕櫚 3.中智 4.再來人 5.學美；錄取滿意度排名：1.美勤 2.世畢盟 3.中智 4.學美 5.澳際《柳葉刀 The Lancet》：碳水化合物質量
和人類健康：一系列系統評價
和薈萃分析
｜Carbohydrate quality and human health: a series of systematic reviews and meta-analyses
An analysis of previous data covering 135 million person-years reveals the health effects of consuming dietary fiber. It』s good news for people who eat whole grains: A diet high in fiber means less risk of heart disease, certain cancers, diabetes, overweight and high blood pressure.
對之前覆蓋 1.35 億人次的數據的分析揭示了食用膳食纖維對健康的影響。 對於吃全穀物的人來說，這是個好消息：高纖維飲食意味着患心臟病、某些癌症、糖尿病、超重和高血壓的風險較低。
January 2019
Background
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.
以前解釋碳水化合物質量與健康之間關係的系統評價和薈萃分析通常檢查單一標誌物和有限數量的臨床結果。 我們的目的是更精確地量化幾種標記物的預測潛力，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證據基礎。
Methods
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. 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. 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.
我們對從數據庫建立到2017年4月30日發表的前瞻性研究以及從數據庫建立到2018年2月28日發表的隨機對照試驗進行了一系列系統評價和薈萃分析，這些研究報告了碳水化合物質量和非傳染性疾病的指標 發病率、死亡率和危險因素。 研究是通過在 PubMed、Ovid MEDLINE、Embase 和 Cochrane 對照試驗中心註冊庫中檢索以及手動檢索以前的出版物來確定的。 我們排除了對患有慢性疾病的參與者進行報告的前瞻性研究和試驗，以及減肥試驗或涉及補充劑的試驗。 搜索、數據提取和偏差評估都是獨立重複的。 通過敏感性分析、薈萃回歸、劑量反應測試和亞組分析來考慮隨機效應模型匯總估計值的穩健性。 GRADE 方法用於評估證據質量。
Findings
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. 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. 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.
分析中納入了來自 185 項前瞻性研究和 58 項臨床試驗（涉及 4635 名成年參與者）的近 1.35 億人年數據。 觀察數據表明，膳食纖維攝入量最高的人群與膳食纖維攝入量最低的人群進行比較時，全因死亡率和心血管相關死亡率以及冠心病、中風發病率和死亡率、2型糖尿病和結直腸癌的發病率降低了 15-30% 臨床試驗 與膳食纖維攝入量較高和較低的情況相比，體重、收縮壓和總膽固醇顯着降低。 當每日膳食纖維攝入量在 25 克至 29 克之間時，與一系列關鍵結果相關的風險降低幅度最大。 劑量反應曲線表明，攝入更多的膳食纖維可以為預防心血管疾病、2 型糖尿病、結直腸癌和乳腺癌帶來更大的好處。 在全穀物攝入量方面也觀察到了類似的結果。 當比較低血糖指數或負荷而不是高血糖指數或負荷的飲食效果時，觀察數據發現風險降低較小或沒有。 碳水化合物質量與關鍵結果之間關係的證據確定性被評為膳食纖維為中等、全穀物為低至中等、膳食血糖指數和血糖負荷為低至極低。 有關其他飲食暴露的數據很少。
Interpretation
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. 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.
與相對較高的膳食纖維和全穀物攝入量相關的前瞻性研究和臨床試驗的結果是互補的，並且引人注目的劑量反應證據表明，與幾種非傳染性疾病的關係可能是因果關係。 實施增加膳食纖維攝入量和用全穀物替代精製穀物的建議預計將有利於人類健康。 該研究的一個主要優勢是能夠通過一項研究中的隊列研究和隨機試驗來檢查與一系列非傳染性疾病結果相關的碳水化合物質量的關鍵指標。 我們的研究結果僅限於降低廣大人群的風險，而不是降低慢性病患者的風險。
Figure_1 Dose-response relationships between total dietary fibre and critical clinical outcomes based on data from prospective studies 總膳食纖維
(A) Total fibre and all-cause mortality. 68 183 deaths over 11·3 million person-years. Assuming linearity a risk ratio of 0·93 (95% CI 0·90–0·95) was observed for every 8 g more fibre consumed per day.
(B) Total fibre and incidence of coronary heart disease. 6449 deaths over 2·5 million person-years. Assuming linearity a risk ratio of 0·81 (0·73–0·90) was observed for every 8 g more fibre consumed per day.
(C) Total fibre and incidence of type 2 diabetes. 22 450 cases over 3·2 million person-years. Assuming linearity a risk ratio of 0·85 (0·82–0·89) was observed for every 8 g more fibre consumed per day.
(D) Total fibre and incidence of colorectal cancer. 20 009 cases over 20·9 million person-years. Assuming linearity a risk ratio of 0·92 (0·89–0·95) was observed for every 8 g more fibre consumed per day.
Introduction
Before the mid-20th century, carbohydrates were principally regarded as an energy source, and nutrition recommendations suggested that carbohydrates should contribute to the energy deficit remaining after taking into account recommended intakes of fat and protein. From the mid-1950s, awareness increased of the potential of sugar (principally sucrose) to increase the risk of dental caries, and in the 1960s the view that sugar was a major cause of obesity, type 2 diabetes, and cardiovascular disease was promoted. A substantial body of experimental, epidemiological, and clinical trial data have accumulated since these early observations. On the basis of extensive systematic reviews and meta-analyses, in 2015, WHO issued a recommendation, that individuals reduce intake to less than 10% of total energy. They also issued a conditional recommendation suggesting that even greater benefit could accrue if intakes of sugar are less than 5% of total energy. Similar recommendations have been made by national governments and professional organisations worldwide.
在20世紀中葉之前，碳水化合物主要被視為一種能量來源，營養建議表明，考慮到脂肪和蛋白質的推薦攝入量後，碳水化合物應該有助於彌補剩餘的能量不足。 從 20 世紀 50 年代中期開始，人們對糖（主要是蔗糖）增加齲齒風險的認識不斷提高，而在 20 世紀 60 年代，糖是肥胖、2 型糖尿病和心血管疾病的主要原因的觀點得到推廣。 自這些早期觀察以來，已經積累了大量的實驗、流行病學和臨床試驗數據。 在廣泛的系統評價和薈萃分析的基礎上，2015年，世界衛生組織發佈建議，個人將攝入量減少到總能量的10%以下。 他們還發佈了一項有條件的建議，表明如果糖的攝入量低於總能量的 5%，可能會產生更大的益處。 世界各國政府和專業組織也提出了類似的建議。
Figure_2 Dose-response relationships between whole grain intake and critical clinical outcomes based on data from prospective studies 全穀物
(A) Whole grain intake and all-cause mortality. 88 347 deaths over 8·2 million person-years. Assuming linearity a risk ratio of 0·94 (95% CI 0·92–0·95) was observed for every 15 g more whole grains consumed per day.
(B) Whole grain intake and incidence of coronary heart disease. 6587 cases over 2·4 million person-years. Assuming linearity a risk ratio of 0·93 (0·89–0·98) was observed for every 15 g more whole grains consumed per day.
(C) Whole grain intake and incidence of type 2 diabetes. 13 147 cases over 3·5 million person-years. Assuming linearity a risk ratio of 0·88 (0·81–0·95) was observed for every 15 g more whole grains consumed per day.
(D) Whole grain intake and incidence of colorectal cancer. 6056 cases over 5·7 million person-years. Assuming linearity a risk ratio of 0·97 (0·95–0·99) was observed for every 15 g more whole grains consumed per day.
Research in contextEvidence before this study
Foods containing carbohydrate consisting principally of sugars, starches, and dietary fibre (non-starch polysaccharide) provide the main source of dietary energy for people worldwide. The role of free sugars as a determinant of adverse health outcomes has been clarified, and clear guidelines relating to their restriction issued. Dietary fibre and some starches are associated with health benefits. Dietary guidelines typically encourage regular consumption of vegetables, cereals, pulses, and whole fruit, which are rich sources of dietary fibre and some starches, as well as other health promoting nutrients. However, previous systematic reviews and meta-analyses examining the relationship between starches and dietary fibre and health outcomes have usually examined a single indicator of carbohydrate quality and a limited number of disease outcomes. Thus, it has not been possible to establish the extent to which the predictive potential of these indicators applies across the spectrum of non-communicable disease, nor which are most useful in nutrition guidelines or when recommending food choices. Quantitative recommendations relating to dietary fibre do not have a strong evidence base. We searched PubMed, Ovid MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for prospective studies published from database inception to April 30, 2017, and randomised controlled trials published from database inception to Feb 28, 2018, and by hand searching of previous publications. Prospective studies and trials reporting on participants with a chronic disease, and weight loss trials or trials involving supplements were excluded. Robustness of pooled estimates from random-effects models was considered with sensitivity analyses, meta-regression, dose-response testing, and subgroup analyses.
含有主要由糖、澱粉和膳食纖維（非澱粉多糖）組成的碳水化合物的食物為全世界人民提供了膳食能量的主要來源。 游離糖作為不良健康結果決定因素的作用已得到澄清，並發布了與其限制相關的明確指南。 膳食纖維和一些澱粉對健康有益。 膳食指南通常鼓勵定期食用蔬菜、穀物、豆類和整個水果，這些都是膳食纖維和一些澱粉以及其他促進健康的營養素的豐富來源。 然而，之前檢查澱粉和膳食纖維與健康結果之間關係的系統評價和薈萃分析通常檢查碳水化合物質量的單一指標和有限數量的疾病結果。 因此，尚無法確定這些指標的預測潛力在多大程度上適用於所有非傳染性疾病，也無法確定哪些指標在營養指南或推薦食物選擇時最有用。 與膳食纖維相關的定量建議沒有強有力的證據基礎。 我們檢索了 PubMed、Ovid MEDLINE、Embase 和 Cochrane 對照試驗中央註冊庫，查找從數據庫建立到 2017 年 4 月 30 日發表的前瞻性研究，以及從數據庫建立到 2018 年 2 月 28 日發表的隨機對照試驗，並手動檢索了以前的研究 出版物。 對患有慢性疾病的參與者進行前瞻性研究和試驗，以及減肥試驗或涉及補充劑的試驗被排除在外。 通過敏感性分析、薈萃回歸、劑量反應測試和亞組分析來考慮隨機效應模型匯總估計值的穩健性。
Figure_3 Dose-response relationships between dietary glycaemic index and critical clinical outcomes based on data from prospective studies 膳食血糖指數
(A) Glycaemic index and all-cause mortality. 7699 deaths over 0·6 million person-years. Assuming linearity a risk ratio of 1·16 (0·90– 1·49) was observed for every 10 glycaemic index unit increase per day.
(B) Glycaemic index and incidence of coronary heart disease. 7240 cases over 2·4 million person-years. Assuming linearity a risk ratio of 1·09 (0·94–1·27) was observed for every 10 glycaemic index unit increase per day.
(C) Glycaemic index and incidence of type 2 diabetes. 31 780 cases over 4·9 million person-years. Assuming linearity a risk ratio of 1·10 (1·00–1·20) was observed for every 10 glycaemic index unit increase per day.
(D) Glycaemic index and incidence of colorectal cancer. 10 390 cases over 6·5 million person-years. Assuming linearity a risk ratio of 1·05 (1·00–1·10) was observed for every 10 glycaemic index unit increase per day.
Added value of this study
We did a systematic review and meta-analyses of prospective studies and clinical trials reporting on the relationship between the most widely studied indicators of carbohydrate quality (ie, dietary fibre, whole grains or pulses, dietary glycaemic index, or glycaemic load) and mortality and incidence of a wide range of non-communicable diseases and their risk factors. Parallel consideration of prospective studies and clinical trials has enabled an exploration of the extent to which changes in cardiometabolic risk factors associated with altering intake of dietary carbohydrate align with the effect of carbohydrate quality on disease risk observed in the prospective studies. Dose-response curves were generated and the benefits from different amounts of total dietary fibre were calculated. The approach recommended by the GRADE Working Group has been used to assess the quality of evidence and the importance of the observed associations that influence confidence in nutrition recommendations.
我們對前瞻性研究和臨床試驗進行了系統回顧和薈萃分析，報告了最廣泛研究的碳水化合物質量指標（即膳食纖維、全穀物或豆類、膳食血糖指數或血糖負荷）與死亡率和死亡率之間的關係。 多種非傳染性疾病的發病率及其危險因素。 前瞻性研究和臨床試驗的並行考慮使得我們能夠探索與改變膳食碳水化合物攝入量相關的心臟代謝危險因素的變化與前瞻性研究中觀察到的碳水化合物質量對疾病風險的影響的程度。 生成劑量反應曲線，並計算不同含量的總膳食纖維的益處。 GRADE 工作組推薦的方法已用於評估證據的質量以及觀察到的影響營養建議信心的關聯的重要性。
Figure_4 Summary forest plots of key outcomes from clinical trials 臨床試驗主要結果的森林圖摘要
(A) Higher compared with lower total fibre intakes.
(B) Higher compared with lower whole grain intakes.
(C) Comparison of diets characterised by lower compared with higher glycaemic index foods.
Implications of all the available evidence
The complementary findings from prospective studies and clinical trials, which show that higher intakes of dietary fibre or whole grains are associated with a reduction in the risk of mortality and incidence of a wide range of non-communicable diseases and their risk factors, provide convincing evidence for nutrition recommendations to replace refined grains with whole grains and increase dietary fibre to at least 25–29 g per day, with additional benefits likely to accrue with greater intakes. Considering current evidence, dietary glycaemic index or glycaemic load might be less useful as overall measures of carbohydrate quality than dietary fibre and whole grain content.
It is more than half a century since epidemiological observations, largely in Africa, suggested that processing of cereal-based foods (grains) with removal of what came to be called dietary fibre, rather than excessive intakes of sugar, were key determinants of both cardiometabolic and large bowel diseases. Nevertheless, until relatively recently, rather less attention has been given to starches and dietary fibre, the other major components of dietary carbohydrate. Although nutrition guidelines issued by many governments and professional organisations encourage increased consumption of vegetables, fruit, and whole grains, fewer quantitative guidelines for sources and intakes of dietary fibre and starch are available. We report here on indicators of carbohydrate quality and non-communicable disease (NCD) incidence, mortality, and risk factors.
This study is essential at this time of increased interest in the area of nutrition and NCDs, and growing knowledge of the impact of carbohydrate intake on public health. The research was commissioned by WHO to inform the development of updated recommendations regarding carbohydrate intake.
前瞻性研究和臨床試驗的補充結果表明，膳食纖維或全穀物的攝入量較高與死亡率風險和多種非傳染性疾病及其危險因素髮病率的降低有關，這提供了令人信服的證據 營養建議用全穀物代替精製穀物，並將膳食纖維增加到每天至少 25-29 克，攝入量增加可能會帶來額外的好處。 考慮到目前的證據，膳食血糖指數或血糖負荷作為碳水化合物質量的總體衡量指標可能不如膳食纖維和全穀物含量有用。
半個多世紀以來，流行病學觀察（主要是在非洲）表明，加工穀類食品（穀物）並去除所謂的膳食纖維，而不是過量攝入糖，是心臟代謝的關鍵決定因素。 和大腸疾病。 然而，直到最近，人們對澱粉和膳食纖維（膳食碳水化合物的其他主要成分）的關注還相當少。 儘管許多政府和專業組織發佈的營養指南鼓勵增加蔬菜、水果和全穀物的消費，但關於膳食纖維和澱粉的來源和攝入量的定量指南卻較少。 我們在此報告碳水化合物質量和非傳染性疾病 (NCD) 發病率、死亡率和風險因素的指標。
在人們對營養和非傳染性疾病領域的興趣日益濃厚，以及人們對碳水化合物攝入對公共健康影響的認識不斷加深的情況下，這項研究至關重要。 這項研究是由世界衛生組織委託進行的，旨在為制定有關碳水化合物攝入量的最新建議提供信息。
Reynolds A, Mann J, Cummings J, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses[J]. The Lancet, 2019, 393(10170): 434-445.
