Mann J I, Cummings J H
Department of Human Nutrition and the Edgar National Centre for Diabetes Research, University of Otago, P.O. Box 913, Dunedin, New Zealand.
Nutr Metab Cardiovasc Dis. 2009 Mar;19(3):226-9. doi: 10.1016/j.numecd.2009.02.002.
There is impressive evidence from epidemiological and experimental studies that dietary fibre derived form vegetables, fruit and wholegrain cereals protects against and may be useful in the treatment of a wide range of diseases. However, while there is some evidence of benefit of extracted and synthetic fibres in terms of lowering levels of cardiovascular risk factors, improving measures of glycaemic control and gastrointestinal function, epidemiological confirmation of clinical benefit and long term safety are lacking. An appropriate definition of dietary fibre is essential, given that claiming a food is high in dietary fibre is in effect making a health claim, without formally doing so. The new Codex definition acknowledges the difference between naturally occurring carbohydrate polymers which are neither digested nor absorbed in the human small intestine and synthetic or extracted polymers. However the latter two groups may also be defined as dietary fibre provided "beneficial physiological effect has been demonstrated by generally accepted scientific evidence". Given the need for a definition of dietary fibre which can be used for food labelling, setting nutrient reference values and decisions relating to health claims it is important to achieve agreement as to what constitutes a meaningful physiological effect and the level of evidence required to be certain of such effect.
来自流行病学和实验研究的大量证据表明，源自蔬菜、水果和全谷物的膳食纤维可预防多种疾病，并可能对其治疗有益。然而，尽管有一些证据表明提取纤维和合成纤维在降低心血管危险因素水平、改善血糖控制指标和胃肠功能方面有益，但缺乏临床益处和长期安全性的流行病学确认。鉴于宣称一种食物富含膳食纤维实际上就是在提出健康声明，却没有正式这样做，因此对膳食纤维进行恰当定义至关重要。新的食品法典定义承认天然存在的碳水化合物聚合物（在人体小肠中既不被消化也不被吸收）与合成或提取聚合物之间的差异。然而，后两类也可被定义为膳食纤维，前提是“已通过普遍接受的科学证据证明其具有有益的生理作用”。鉴于需要一个可用于食品标签、设定营养素参考值以及与健康声明相关决策的膳食纤维定义，就什么构成有意义的生理作用以及确定这种作用所需的证据水平达成一致意见很重要。
