Calibrated Diets and Human Intestinal Microflora (AlimIntest)

The main objective of the study is to realized a collection of feces in order to study the modification of the intestinal microflora according to alimentary fibres

Human intestinal tract count up to 1014 bacteria. We consider that each bacterial flora is composed of more than 500 different species among which only 20% are cultivable. Although this flora is well unknown, it is known that it play a major role in the metabolism of the eating fibers. Dysfunctions of this flora may be implied in numerous local and general pathologies.

It has been shown that probiotics and prebiotics are able to act upon the intestinal flora. On the basis of the personal real-life, it is generally considered acquired that our diet modifies this flora. However not many studies have validated this hypothesis with human normal diet (not artificially enriched with prebiotics or probiotics). The idea that our diet can modified the functioning of our intestinal flora (and so favor certain pathologies or activate recovery) is widely hypothetic.

A best knowledge of the diversity of this flora and to put at disposal tools to study it on a large scale could allow to answer this question. The demonstration that some food components could modify the composition or the functioning of this flora would have considerable consequences in medicine and food processing industry.

• Dietary Supplement: 10 g of fibres per day
  10 g of fibres per day
  Other Name: low fibres
• Dietary Supplement: 40 g of fibres per day
  40g of fibres per day
  Other Name: high fibres

• Experimental: A
  diet composed of 10g of fibre per day
  Intervention: Dietary Supplement: 10 g of fibres per day
• Experimental: B
  diet composed of 40g of fibre per day
  Intervention: Dietary Supplement: 40 g of fibres per day

• Suau A, Bonnet R, Sutren M, Godon JJ, Gibson GR, Collins MD, Doré J. Direct analysis of genes encoding 16S rRNA from complex communities reveals many novel molecular species within the human gut. Appl Environ Microbiol. 1999 Nov;65(11):4799-807.
• Aaltonen LA, Peltomäki P, Leach FS, Sistonen P, Pylkkänen L, Mecklin JP, Järvinen H, Powell SM, Jen J, Hamilton SR, et al. Clues to the pathogenesis of familial colorectal cancer. Science. 1993 May 7;260(5109):812-6.
• Moore WE, Moore LH. Intestinal floras of populations that have a high risk of colon cancer. Appl Environ Microbiol. 1995 Sep;61(9):3202-7.
• Black AE, Coward WA, Cole TJ, Prentice AM. Human energy expenditure in affluent societies: an analysis of 574 doubly-labelled water measurements. Eur J Clin Nutr. 1996 Feb;50(2):72-92.
• Robinson RR, Feirtag J, Slavin JL. Effects of dietary arabinogalactan on gastrointestinal and blood parameters in healthy human subjects. J Am Coll Nutr. 2001 Aug;20(4):279-85.
• Tuohy KM, Kolida S, Lustenberger AM, Gibson GR. The prebiotic effects of biscuits containing partially hydrolysed guar gum and fructo-oligosaccharides--a human volunteer study. Br J Nutr. 2001 Sep;86(3):341-8.
• Chinda D, Nakaji S, Fukuda S, Sakamoto J, Shimoyama T, Nakamura T, Fujisawa T, Terada A, Sugawara K. The fermentation of different dietary fibers is associated with fecal clostridia levels in men. J Nutr. 2004 Aug;134(8):1881-6.

Inclusion Criteria:

• BMI between 18,5 and 25

Exclusion Criteria:

• Antibiotherapy in the previous month
• Current Antibiotherapy
• Gastro-intestinal dysfunction
• Pregnancy, parturient and feeding woman
• Person deprived of freedom by judiciary or administrative decision, person in legal protection,
• Prebiotic and/or osmotic laxatives in the previous month
• Preparation for coloscopy in the previous month

• Centre de Recherche en Nutrition Humaine Rhone-Alpe
• Institut National de la Recherche Agronomique