title: Impact of a very low-energy diet on the fecal microbiota of obese individuals.
abstract: OBJECTIVE
  Study how the dietary intake affects the fecal microbiota of a group of obese individuals after a 6-week very low-energy diet (VLED) and thereafter during a follow-up period of 5, 8, and 12 months. Additionally, we compared two different methods, fluorescent in situ hybridization (FISH) and real-time PCR (qPCR), for the quantification of fecal samples.
  
  
  METHODS
  Sixteen subjects participated in a 12-month dietary intervention which consisted of a VLED high in protein and low in carbohydrates followed by a personalized diet plan, combined with exercise and lifestyle counseling. Fecal samples were analyzed using qPCR, FISH, and denaturing gradient gel electrophoresis.
  
  
  RESULTS
  The VLED affected the fecal microbiota, in particular bifidobacteria that decreased approximately two logs compared with the baseline numbers. The change in numbers of the bacterial groups studied followed the dietary intake and not the weight variations during the 12-month intervention. Methanogens were detected in 56% of the participants at every sampling point, regardless of the dietary intake. Moreover, although absolute numbers of comparable bacterial groups were similar between FISH and qPCR measurements, relative proportions were higher according to FISH results.
  
  
  CONCLUSIONS
  Changes in the fecal microbial numbers of obese individuals were primarily affected by the dietary intake rather than weight changes.
authors.affiliation: VTT Technical Research Centre of Finland, Espoo, Finland, catarina.simoes@helsinki.fi.
authors.forename: C D
authors.initials: CD
authors.lastname: Simões
authors.forename: J
authors.initials: J
authors.lastname: Maukonen
authors.forename: K P
authors.initials: KP
authors.lastname: Scott
authors.forename: K A
authors.initials: KA
authors.lastname: Virtanen
authors.forename: K H
authors.initials: KH
authors.lastname: Pietiläinen
authors.forename: M
authors.initials: M
authors.lastname: Saarela
mesh_terms: D015992:Body Mass Index; D001835:Body Weight; D031204:Caloric Restriction; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D002149:Energy Intake; D015444:Exercise; D005243:Feces / Q000382:microbiology*; D005247:Feeding Behavior; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008019:Life Style; D008297:Male; D064307:Microbiota; D009765:Obesity / Q000178:diet therapy* / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D044465:White People
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S