膳食纖維是一種多糖,它既不能被胃腸道消化吸收,也不能產(chǎn)生能量。因此,曾一度被認(rèn)為是一種“無營養(yǎng)物質(zhì)”而長期得不到足夠的重視。近年來,隨著營養(yǎng)學(xué)和相關(guān)科學(xué)的深入發(fā)展,人們逐漸發(fā)現(xiàn)了膳食纖維具有相當(dāng)重要的生理作用。以致于在膳食構(gòu)成越來越精細(xì)的今天,膳食纖維更成為學(xué)術(shù)界和普通百姓關(guān)注的物質(zhì),并被營養(yǎng)學(xué)家列為“第七營養(yǎng)素”,是平衡膳食結(jié)構(gòu)的必需營養(yǎng)素之一。 全球面臨膳食纖維攝入不足問題! |
那么,30g膳食纖維到底是怎樣的呢,如下圖所示。結(jié)合我國居民膳食纖維攝入明顯不足,想要在短時間內(nèi)改變大眾的飲食習(xí)慣,從日常飲食增加膳食纖維攝入量并不容易,所以人們需要通過飲食其他食品或藥品來達(dá)到膳食纖維正常量。 膳食纖維分類 膳食纖維按照其溶解性,可分為水溶性膳食纖維和水不溶性膳食纖維。水溶性膳食纖維由于其良好的溶解性、穩(wěn)定性以及平和的口感等特性,應(yīng)用于飲料、乳制品、糖果、啤酒等領(lǐng)域,水不溶性膳食纖維因其良好的溶脹性能,能夠為產(chǎn)品提供必要的體積,常用于面包、飲料、餅干、乳制品等食品中。 水溶性膳食纖維是能夠溶解于水中的纖維類型。具有黏性,能在腸道中大量吸收水分,使糞便保持柔軟狀態(tài)。水溶性纖維能有效促進(jìn)腸道有益菌繁殖,調(diào)節(jié)腸道微生態(tài)平衡。常見的水溶性膳食纖維包括聚葡萄糖、菊粉、低聚果糖、低聚木糖、低聚異麥芽糖、低聚半乳糖、大豆低聚糖等。 水不溶性膳食纖維主要包括纖維素、半纖維素和木質(zhì)素等。水不溶性膳食纖維能吸收水分,軟化糞便,增加糞便的體積,以刺激腸的蠕動,加速排便,從而減少糞便中有害物質(zhì)與腸道接觸的時間。 膳食纖維能帶來哪些益處? ? 減少疾病風(fēng)險及降低全因死亡率 2019年Lancet上發(fā)表的一項大型研究,涉及1.35億人年的前瞻性隊列研究數(shù)據(jù)和4635名成年人的臨床試驗數(shù)據(jù),發(fā)現(xiàn)對于廣大健康人群,膳食纖維攝入與慢性病發(fā)病和死亡率的降低顯著相關(guān):每增加8g/天的膳食纖維攝入量,可降低約7%全因死亡風(fēng)險、19%冠心病風(fēng)險、15%糖尿病風(fēng)險、8%大腸癌風(fēng)險。 研究發(fā)現(xiàn),膳食纖維還與直腸癌(CRC)死亡率和全因死亡率的下降、肺癌風(fēng)險降低、中年婦女高血壓風(fēng)險的降低等有關(guān)。 ? 改善胃腸道功能 2020年英國《自然》雜志子刊發(fā)表綜述文章,表明每攝入1g小麥纖維,就能將腸道通過時間減少0.78h;幾乎所有種類的膳食纖維,都能促進(jìn)排便,并維持排便的穩(wěn)定性。 研究表明,膳食纖維還可降低放療患者急性和長期的胃腸道毒性、降低大便失禁風(fēng)險、幫助抵抗腸道病原體的感染等。 近年來,微生物組的研究,進(jìn)一步揭示了膳食纖維是許多體內(nèi)有益微生物的食物,能夠促進(jìn)有益微生物的生長,顯示出“益生元”的特性,既能刺激有益腸道菌群生長,如雙歧桿菌和乳酸菌,也有利于產(chǎn)生丁酸等短鏈脂肪酸,促進(jìn)腸道健康。 ? 改善肥胖、調(diào)節(jié)血糖 2017年American journal of clinical nutrition上綜述了12項持續(xù)時間2-17周的隨機(jī)對照試驗,共涉及609名參與者,發(fā)現(xiàn)與對照組相比,可溶性膳食纖維最多可以幫助降低BMI 0.84,減重2.52kg,減脂0.41%,空腹血糖降低0.17mmol/L,空腹胰島素水平降低15.88pmol/L。 經(jīng)研究還發(fā)現(xiàn),每日50g膳食纖維可顯著改善2型糖尿病人糖脂代謝、膳食纖維可富集關(guān)鍵腸道菌快速有效地改善2型糖尿病。 ? 其它益處 多項研究表明,膳食纖維在緩解慢性炎癥、改善IBS和IBD、增強(qiáng)中年人的肌肉量和力量、預(yù)防憩室炎等方面也具有潛在的健康益處。 總而言之,膳食纖維對于人體健康來說十分重要,膳食纖維在改善肥胖、糖尿病、胃腸道、降低疾病發(fā)生/死亡風(fēng)險等方面的益處亦不容忽視,人體長期攝入富含膳食纖維的食物或補充膳食纖維的產(chǎn)品,不僅能為身體提供營養(yǎng)物質(zhì),還有助于促進(jìn)健康的胃腸道功能,控制體重,減少疾病風(fēng)險及降低全因死亡率,對提升整體健康具有重要作用。 1. 《世界胃腸病學(xué)組織全球指南 飲食與腸道》&《中國居民膳食纖維攝入白皮書》 &《中國居民膳食營養(yǎng)素參考攝入量》 2. Stephen J O'Keefe. The association between dietary fibre deficiency and high-income lifestyle-associated diseases: Burkitt's hypothesis revisited[J]. The Lancet Gastroenterology & Hepatology, 2019, 4(12). 3.《膳食纖維在食品領(lǐng)域中應(yīng)用及其市場前景分析》. 4. Andrew Reynolds, Jim Mann, John Cummings, Nicola Winter, Evelyn Mete, Lisa Te Morenga. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses[J]. The Lancet, 2019, 393(10170). 5. Song Mingyang, Wu Kana, Meyerhardt Jeffrey A, Ogino Shuji, Wang Molin, Fuchs Charles S, Giovannucci Edward L, Chan Andrew T. Fiber Intake and Survival After Colorectal Cancer Diagnosis[J]. JAMA oncology,2018,4(1). 6. Yang Jae Jeong, Yu Danxia, Xiang YongBing, et al. Association of Dietary Fiber and Yogurt Consumption With Lung Cancer Risk: A Pooled Analysis[J]. JAMA oncology, 2020, 6(2). 7. Du Peng, Luo Kaifeng, Wang Yali, Xiao Qi, Xiao Jiansheng, Li Yong, Zhang Xingjian. Intake of Dietary Fiber From Grains and the Risk of Hypertension in Late Midlife Women: Results From the SWAN Study [J]. Frontiers in Nutrition,2021. 8. Gill Samantha K, Rossi Megan, Bajka Balazs, Whelan Kevin. Dietary fibre in gastrointestinal health and disease[J]. Nature Reviews Gastroenterology & Hepatology, 2020, 18(2). 9. Wedlake Linda, Shaw Clare, McNair Helen, et al. Randomized controlled trial of dietary fiber for the prevention of radiation-induced gastrointestinal toxicity during pelvic radiotherapy[J]. The American journal of clinical nutrition, 2017, 106(3). 10. Kyle Staller, Mingyang Song, Francine Grodstein, et al. Increased Long-term Dietary Fiber Intake is Associated With Decreased Risk of Fecal Incontinence in Older Women[J]. Gastroenterology, 2018. 11. Neumann Mareike, Steimle Alex, Grant Erica T, et al. Deprivation of dietary fiber in specific-pathogen-free mice promotes susceptibility to the intestinal mucosal pathogen Citrobacter rodentium[J]. Gut microbes, 2021, 13(1). 12. Thompson Sharon V, Hannon Bridget A, An Ruopeng,Holscher Hannah D. Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials[J]. The American journal of clinical nutrition, 2017, 106(6). 13. Chandalia Manisha, Garg Abhimanyu, Lutjohann Dieter, et al. Beneficial Effects of High Dietary Fiber Intake in Patients with Type 2 Diabetes Mellitus[J]. The New England Journal of Medicine, 2000,3 42(19). 14. Liping Zhao, Feng Zhang, Xiaoying Ding, et al. Gut bacteria selectively promoted by dietary fibers alleviate type 2 diabetes[J]. Science, 2018, 359(6380). 15. Ma Wenjie, Nguyen Long H, Song Mingyang, et al. Dietary fiber intake, the gut microbiome, and chronic systemic inflammation in a cohort of adult men[J]. Genome medicine, 2021, 13(1). 16. So Daniel, Gibson Peter R, Muir Jane G, Yao Chu K. Dietary fibres and IBS: translating functional characteristics to clinical value in the era of personalised medicine[J]. Gut, 2021. 17. Chu K Yao, Heidi M Staudacher. The low-fibre diet: contender in IBD, or has it had its time?[J]. The Lancet Gastroenterology & Hepatology, 2019, 4(5). 18. Frampton James, Murphy Kevin G, Frost Gary, Chambers Edward S. Higher dietary fibre intake is associated with increased skeletal muscle mass and strength in adults aged 40 years and older[J]. Journal of cachexia, sarcopenia and muscle, 2021. 19. Ma Wenjie, Nguyen Long H, Song Mingyang, et al. Intake of Dietary Fiber, Fruits, and Vegetables and Risk of Diverticulitis[J]. The American journal of gastroenterology, 2019, 114(9). |