cron-web.org

[A1CR]

It appears that that there may be an interaction between CR,
our diet and
our intestinal bacteria in how disposed we are in developing
cancer. Was it
surprising that the health-promoting
http://en.wikipedia.org/wiki/Bifidobacteria and the
intestinal predominant http://en.wikipedia.org/wiki/E._coli
were not found in Table 1? The family Lachnospiraceae of
bacteria have previously been characterized in caries,
but the genus identified in this paper may be a new species.
Related to
these studies and from the same group, is the previous
free-full-text
http://tinyurl.com/m2mxo paper. Another related paper
(reference 35 by the same as the (1) paper from the authors'
group) is shown in excerpt below. Mediterranean diets have
much affect, it seems.

1. Mai V, Colbert LH, Perkins SN, Schatzkin A, Hursting SD.
Intestinal microbiota: A potential diet-responsive
prevention target in
Apc(Min) mice.

Mol Carcinog. 2006 Aug 23; [Epub ahead of print] PMID: 16929480

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16929480


Abstract:

We previously [probably the PMID: 12702556
http://tinyurl.com/m2mxo
free full-text paper] reported that two dietary regimens,
calorie
restriction (CR) and a high olive oil-containing diet
supplemented with a
freeze-dried fruit and vegetable extract (OFV), reduced the
development of
intestinal adenomas in Apc(Min) mice by 57% and 33%,
respectively, compared
to control mice fed a defined diet ad libitum. The OFV diet
was designed to
have a strong effect on the composition of the intestinal
microbiota through
its high content of fiber, which represents a major source
of fermentable
substrate for the gut bacteria. We hypothesized that some of
the observed
effects of diet on intestinal carcinogenesis might be
mediated by
diet-related changes in the bacterial species that thrive in
the gut. ...
fluorescent in situ hybridization (FISH) and denaturing
gradient gel
electrophoresis (DGGE) ... The OFV diet changed the overall
composition of
the intestinal microbiota, smaller changes were observed for
the CR diet.
Furthermore, we detected a 16S rDNA fragment associated with
mice that did
not develop polyps. Sequence analysis suggested that
hitherto unidentified
bacteria belonging to the family Lachnospiraceae (order
Clostridiales) were
its source. Thus, these bacteria may be an indicator of
intestinal
conditions associated with reduced intestinal carcinogenesis
in Apc(Min)
mice.

Excerpts:

... The mammalian intestinal tract is inhabited by
large numbers
(10^12 to 10^14) of microorganisms, mainly bacteria, fungi,
and protozoa.
These microbes may contribute to health by (i) metabolizing
pro-carcinogens
and carcinogens, and facilitating their excretion through
binding [[7],[8]],
(ii) activating beneficial compounds such as phytoestrogens
for uptake by
the colonic epithelium [[9]], (iii) producing beneficial
fermentation
end-products such as the short-chain fatty acid butyrate
[[2],[10]], (iv)
excluding pathogenic microorganisms [[11]], and (v)
stimulating the immune
system [[12]].

... described in detail elsewhere [21, the previously
reported the
PMID: 12702556 http://tinyurl.com/m2mxo free full-text
paper] ... exercise
(EX) ... 6-wk-old male C57BL/6J-ApcMin/+ mice (ApcMin) ...
(30 mice/group):
(i) control (CON) (fed AIN-76A diet ad libitum); (ii) 40% CR
(fed daily
aliquots of modified AIN-76A diet); (iii) high olive oil
diet supplemented
with a freeze-dried fruit and vegetable extract (OFV) (fed
ad libitum); and
(iv) treadmill running EX (pair-fed to control with AIN-76A
diet). ...
... Mice that consumed the OFV diet contained
significantly more total
bacteria as well as higher numbers of Bacteroides/Prevotella,
eubacteria/clostridia, and lactic acid bacteria in their
large intestines
compared to CON and CR. Although the numbers of
Bacteroides/Prevotella were
higher in the OFV group, the proportion of these bacteria
among the total
microbiota was lower when compared to either CON or CR (20%
vs. 50% and 35%,
respectively (P < 0.05)). In neither group did we detect
positive
hybridization signals for probes directed against
bifidobacteria, or E.
coli, which indicated that these bacteria were not present
in large
intestinal contents at levels above the FISH detection limit
of 10^6-10^7
cells/mL. Although polyps in ApcMin mice develop mostly in
the small
intestines, we were unable to obtain consistent bacterial
numbers by FISH of
the fixed small intestinal contents from these mice.

[...]

... The diet-induced changes in the microbiota that we
observed might
have contributed, at least partially, to the decreased polyp
frequency we
[21, the previously reported the PMID: 12702556
http://tinyurl.com/m2mxo
free full-text paper] for both the CR and OFV diets. ...
here ... few large
intestinal polyps are observed in ApcMin mice on the
C57BL/6J background and
in our studies, we only detected differences between the
treatment groups in
the numbers of small intestinal polyps. The large intestinal
microbiota is
more diverse than that of the small intestine with increased
bacterial
numbers and activities. ... For example butyrate, a
microbial fermentation
product that stimulates cell differentiation and apoptosis
might reach the
small intestine. ...

In conclusion, we observed that a dietary regimen
including olive oil
supplemented with a freeze-dried fruit and vegetable
extract, which we have
previously shown to reduce intestinal carcinogenesis in
ApcMin mice [the
pdf-availed http://tinyurl.com/m8d8o paper] modulated the
composition of the
intestinal microbiota towards a composition that might be
more beneficial.
Thus, our study is suggestive of a potential association
between specific
microbiota composition and carcinogenesis in ApcMin mice. ...

35. Henderson AL, Cao WW, Wang RF, Lu MH, Cerniglia CE.

The effect of food restriction on the composition of
intestinal microflora
in rats.

Exp Gerontol. 1998 May;33(3):239-47.

PMID: 9615922

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=9615922

Abstract:

The effect of a food-restricted diet on the fecal microflora
of rats was studied by determining total anaerobic bacteria,
bacterial cellular fatty acids, and the predominant
intestinal bacteria shown by polymerase chain reaction (PCR)
primers specific for the 16S rRNA gene sequences of 12
bacterial species. Twenty-four female Fischer 344 rats, 57
days old were divided into two groups and maintained on an
NIH-31 diet. One group was fed ad libitum while the other
group received 60% of ad libitum food intake (40% food
restriction supplemented with vitamins and minerals equal to
the ad libitum animals). After 2, 10, and 20 weeks on this
dietary regimen, groups of four animals were sacrificed and
the intestinal contents analyzed for changes in the
bacterial flora. The anaerobic population for two-week
(short-term) food-restricted rats was 3.2 x 10(8) per gram,
slightly less than the 9.1 x 10(8) per gram found in the ad
libitum-fed rats. The anaerobic populations in 20-week food
restricted and ad libitum fed rats were 1.9 x 10(9) and 2.7
x 10(9) per gram, respectively. The total anaerobic
population did not change significantly in either group
during the 20-week study. No statistically significant
differences were observed in the bacterial cellular fatty
acid profiles between the two groups as determined by
gas-liquid chromatography. PCR analysis of the intestinal
contents indicated no significant shifts in the predominant
flora due to dietary changes. The results, using three
different methods to detect changes in the rat intestinal
microflora, suggest that long-term dietary restriction had
little effect on the microflora of female Fischer 344 rats.