生物谷报道：长久以来人们就知道土豆对肠道健康有好处，但一项最新研究证实，土豆或许还对整个免疫系统有利，特别是食用土豆沙拉。结果发表在《化学与工业》（Chemistry & Industry）上。
西班牙科学家发现，用大量生马铃薯淀粉（RPS）喂养的猪有更健康的肠道，这并不意外。但是他们同时发现RPS能降低猪血液中白血球数量，例如白细胞和淋巴细胞。白血球是炎症和其它疾病产生的，它们表明身体存在一定问题。
来自瑞典Goteborg大学的免疫学家Lena Ohman表示，这种现象表明整个身体都处于更健康的状态。RPS喂养的猪白细胞数量降低了15%左右。但Ohman也认为，同时观察到白细胞和淋巴细胞降低是令人吃惊的。
实验中，科学家用RPS喂养猪14周，以分析它们对肠道健康的作用。研究项目负责人 José Francisco Pérez 说：“用RPS的目的是模拟高抗性淀粉的饮食。”
人类不会食用生土豆，但是会食用大量含有抗性淀粉的食物，例如冷煮土豆、豆荚、绿香蕉、意大利面和谷类。大约10%的人类食用淀粉是抗性淀粉，它们不会在小肠中消化，因此最终会进入大肠中发酵。
淀粉摄入能降低大肠癌风险，而且对肠易激综合症（IBS）有利。Ohman小组之前研究发现，对IBS病人而言淋巴细胞数量不会变化，但淋巴细胞会从周围血液聚集到肠道，这意味着IBS至少是部分炎症反应。因此她认为观察到淋巴细胞下降很有意思，或许含有抗性淀粉的食物对IBS病人有利。 （引自教育部科技发展中心）
英文原文链接：http://www.physorg.com/news101952367.html
原始出处:
Journal of the Science of Food and Agriculture
Published Online: 21 Jun 2007
Research Article
Long-term effects on the digestive tract of feeding large amounts of resistant starch: A study in pigs
Daniel Martínez-Puig 1, Marisol Castillo 1, Miquel Nofrarias 2, Eva Creus 1, Dr José F Pérez 1 *
1Animal Nutrition, Management and Welfare Research Group, Departament de Ciència Animal i dels Aliments, 08193 Bellaterra, Barcelona, Spain
2Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
email: José F Pérez (josefrancisco.perez@uab.es)
*Correspondence to José F Pérez, Animal Nutrition, Management and Welfare Research Group, Departament de Ciència Animal i dels Aliments, 08193 Bellaterra, Barcelona, Spain
Funded by:
CICYT; Grant Number: AGL2001-2621-CO2-01
resistant starch ?large bowel fermentation ?short-chain fatty acids ?growing pigs
Abstract
The present study aimed to assess the digestive consequences of the long-term intake of two starches providing different amounts of resistant starch. Growing pigs were used as the animal model and meal-fed for 14 weeks on a diet containing a high amount of either raw potato starch (RPS) or corn starch (CS). Digestive adaptation was chronologically evaluated by measuring organic matter (OM), crude protein (CP), neutral detergent fibre (NDF) and starch digestibility. After 97 days, whole-tract digestibility of OM, CP and NDF was lower for RPS- compared to CS-fed pigs, whereas no differences were observed in faecal starch digestibility. In contrast, starch digestibility was reduced in the proximal compartments (ileum, caecum and proximal colon) of animals fed the RPS diet. The concentration of short-chain fatty acids (SCFAs; P < 0.05), and purine bases (PBs; P < 0.01) was also higher in distal colon and rectum of animals fed the RPS diet. Changes in bacterial community structure (dendogram analyses) were seen in the rectum. Biodiversity tends to increase more in RPS compared to CS fed animals (34.1 vs. 28.8; P = 0.07). Among SCFAs, the proportion of butyrate was two-fold higher in proximal colon digesta of RPS compared to CS fed pigs (0.20 vs. 0.11; P < 0.05). Increased butyrate formation in the colon reduced the number of apoptosis per crypt in the proximal colonic mucosa (0.38 vs. 0.62; P < 0.05). RPS fermentation reduced indices associated with damage to intestinal epithelial cells, such as crypt cell hyperproliferation and magnesium excretion. Long-term ingestion of RPS induces pronounced changes of the digestive tract and their microflora, modifying mineral absorption and colonic morphology for which health benefits are likely to be associated. Copyright © 2007 Society of Chemical Industry
