reports
deficiency
Richard
W. Reilly,
Epidemiologists tion
of
affects
fiber
paid
diet. This investigators cal
and
have modern
in
health,
been
M.D.
yet
to
little
fiber
metabolic
and Joseph
colonic
B. Kirsner,
scientific was in the
properties
attention
of it in the
has
human
called to chemical, of fiber
allow physi-
to interact
with intestinal physiologists and clinicians. The conference was sponsored by the Gastroenterology Section of the University of Chicago and held in the Center for Continuing Education at the University of Chicago on May 17, 1974. There were 34 participants with observers from the American Medical Association, Food and Drug Administration, and the food industry. Dietay
and
fiber
and
intePaction
of bacteria
bile
It was emphasized that dietary fiber is undefined and really unmeasured. Effects on the intestinal tract may be due to fiber directly or to some of its metabolites. Improved analytic methods, biological test systems to quantitate
fiber
effects
and
separation
of
28:
Ph.D.’
to
be
unchanged.
fecal
Fiber the more
streaming
phase
progresses
phase.
We
know
that
characteristics of and bile adsorption, influence
redox
of
and colonic
fiber
spaces,
and
only water
pH in such
the
physical
exchange guess at the distribution,
a complex.
function
Although luminal seem to alter mucosal fecal
has
, cation
wetability but can
surface,
potential
Fiber
also seems to normalize colon, e.g., the solid rapidly than the fluid
in
heterogeneity
factors certainly would function, the effects of are
really
not
known
be-
cause all the investigation to date has been done in “clean,” not feces-containing diarrhea. The definitive study of segmenting activity in the empty colon and in the feces-filled colon neeth to be made. A potential method for sampling the effect of solid colonic content on the mucosa could be undertaken with radiopaque markers (for transit time) which could be related to absorption through changes in mucosal potential difference.
fiber
into its variety of fractions are necessary for further progress. Another route of investigation is suggested by the copolymer chemist’s ability to build very close copies of natural fibers. Such synthetics can be examined before and after they pass through the gut. The important question of whether bacteria carry on normal metabolic activities, once bound to fiber, then could be examined. Secondary bile acids are generated by bacteria in the colon which seem to be most strongly adsorbed to fiber. Bran appears to inhibit 7c-dehydroxylation and thereby may alter bile salt metabolism in the colon, thus changing the composition of the bile salt pool by decreasing deoxycholate. Chenodeoxycholate then increases; cholate is unchanged and the total bile salt pool appears TheAmericanfournalofClinicalNutrition
disorders
M.D.,
suggested that deplewestern diet adversely
or lack
conference interested
and
MARCH
Fiber-deficient
disorders
of the colon
The irritable colon syndrome with constipation manifests increased phasic motility in the distal bowel exaggerated by food. In these instances, as opposed to those with diarrhea, fiber should not increase pain or constipation and might be of real benefit. Controlled studies are indicated. N. Painter has long proposed that diverticular disease is an acquired disease, endemic in western civilization on low fiber diets and attributable to segmentation of the bowel with increased pressure in the colon. Bran causes the formation of a moist stool I
cine,
Section The
Chicago,
1975,
of Gastroenterology, Pritzker School
Chicago,
pp.
293-294.
Illinois
Printed
of
Department of MediMedicine, University of
60637.
in U.S.A.
293
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/3/293/4716325 by Boston University user on 13 January 2019
Fiber
of meetings
REILLY
294
AND
demonstrating
diverticular
disease
in
older
people taking higher fiber diets. In those patients with diverticular disease who do not respond to a normal intake of bran, the operation of myotomy appears to have been successful. However, the decrease in the colonic pressure response to food following this procedure persists only if the patients are maintained on a diet supplemented by fiber postoperalively. The alleged diseases of civilizationdiverticular disease, heart disease, gallstones, polyps, hiatus hernia, appendicitis and cancer, in general, have the same geographic distributions.
There
is a marked
decrease
in fiber
in the
diet in these areas, but there is also an increase in fat, protein, and sugar intake. In such areas, when tested, anaerobic bacteria seem to predominate in the feces. It was suggested that anaerobes degrade cholate to deoxycholate, which may act as a cocarcinogen in the colon. The addition of fiber to the diet inhibits degradation of cholate to deoxycholate. Controversy about the “diseases of civilization” and their distribution was spirited. Appendicitis in fact has decreased by 40% in the last 20 years in
the
ischemic
U.S. heart
;
in disease
Finland is quite
the
incidence high,
but
of cancer
of the colon is low; in the Argentine, the population has a high beef and high fiber intake and a high incidence of colon cancer. Multiple etiologic factors undoubtedly are involved. The major problem with epidemiologic evidence is
that
the
changes
in
dietary
practices
with
industrial/economic development tend to be similar wherever they occur; there is a concurrent increase in consumption of animal products, of fat, of sugar, of refined cereals, and the like. When changes in the consumption of two or more materials are highly correlated, the data cannot provide proof as to which of these is related primarily to the disease under investigation. Unless one can find populations in which individual factors are segregated, the epidemiologic
potheses
evidence
which
can
can
then
only
suggest
be subjected
hy-
to study.
Summary It was agreed by the conference that better analytic techniques and better bioassays were needed. Synthetics, duplicating activities though due to natural fiber, were an intriguing alternative for relating a range of fiber effects to the kind of fiber. Bile salt excretion does not seem to be increased by dietary fiber elevation; rather bile salt metabolism seems to be altered, resulting in decreased deoxycholate and increased chenodeoxycholate . Electrical activity, manometric data, and transit studies must be correlated and further studies along these lines should be done in the normal “dirty” colon, to evaluate effects of intraluminal contents. In general, there appears to be a correlation between low fiber intake and the “diseases of civilization,” but nothing definitive can be said about cause and effect as yet. There are inconsistencies in the geographic evidence relating low fiber diets to disease; perhaps we should be looking for clues in these very inconsistencies.
Proceedings tion.
of the conference
are in prepara-
U
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/3/293/4716325 by Boston University user on 13 January 2019
which lowers viscosity and facilitates easy passage with decreased intracolonic pressure. There was general agreement with these ideas in the approach to diverticular disease involving the sigmoid but they do not readily explain diverticula on the right side of the colon, characterized by a large lumen and fluid bowel content. In addition there have been reports
KIRSNER
deficiency
Richard
W. Reilly,
Epidemiologists tion
of
affects
fiber
paid
diet. This investigators cal
and
have modern
in
health,
been
M.D.
yet
to
little
fiber
metabolic
and Joseph
colonic
B. Kirsner,
scientific was in the
properties
attention
of it in the
has
human
called to chemical, of fiber
allow physi-
to interact
with intestinal physiologists and clinicians. The conference was sponsored by the Gastroenterology Section of the University of Chicago and held in the Center for Continuing Education at the University of Chicago on May 17, 1974. There were 34 participants with observers from the American Medical Association, Food and Drug Administration, and the food industry. Dietay
and
fiber
and
intePaction
of bacteria
bile
It was emphasized that dietary fiber is undefined and really unmeasured. Effects on the intestinal tract may be due to fiber directly or to some of its metabolites. Improved analytic methods, biological test systems to quantitate
fiber
effects
and
separation
of
28:
Ph.D.’
to
be
unchanged.
fecal
Fiber the more
streaming
phase
progresses
phase.
We
know
that
characteristics of and bile adsorption, influence
redox
of
and colonic
fiber
spaces,
and
only water
pH in such
the
physical
exchange guess at the distribution,
a complex.
function
Although luminal seem to alter mucosal fecal
has
, cation
wetability but can
surface,
potential
Fiber
also seems to normalize colon, e.g., the solid rapidly than the fluid
in
heterogeneity
factors certainly would function, the effects of are
really
not
known
be-
cause all the investigation to date has been done in “clean,” not feces-containing diarrhea. The definitive study of segmenting activity in the empty colon and in the feces-filled colon neeth to be made. A potential method for sampling the effect of solid colonic content on the mucosa could be undertaken with radiopaque markers (for transit time) which could be related to absorption through changes in mucosal potential difference.
fiber
into its variety of fractions are necessary for further progress. Another route of investigation is suggested by the copolymer chemist’s ability to build very close copies of natural fibers. Such synthetics can be examined before and after they pass through the gut. The important question of whether bacteria carry on normal metabolic activities, once bound to fiber, then could be examined. Secondary bile acids are generated by bacteria in the colon which seem to be most strongly adsorbed to fiber. Bran appears to inhibit 7c-dehydroxylation and thereby may alter bile salt metabolism in the colon, thus changing the composition of the bile salt pool by decreasing deoxycholate. Chenodeoxycholate then increases; cholate is unchanged and the total bile salt pool appears TheAmericanfournalofClinicalNutrition
disorders
M.D.,
suggested that deplewestern diet adversely
or lack
conference interested
and
MARCH
Fiber-deficient
disorders
of the colon
The irritable colon syndrome with constipation manifests increased phasic motility in the distal bowel exaggerated by food. In these instances, as opposed to those with diarrhea, fiber should not increase pain or constipation and might be of real benefit. Controlled studies are indicated. N. Painter has long proposed that diverticular disease is an acquired disease, endemic in western civilization on low fiber diets and attributable to segmentation of the bowel with increased pressure in the colon. Bran causes the formation of a moist stool I
cine,
Section The
Chicago,
1975,
of Gastroenterology, Pritzker School
Chicago,
pp.
293-294.
Illinois
Printed
of
Department of MediMedicine, University of
60637.
in U.S.A.
293
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/3/293/4716325 by Boston University user on 13 January 2019
Fiber
of meetings
REILLY
294
AND
demonstrating
diverticular
disease
in
older
people taking higher fiber diets. In those patients with diverticular disease who do not respond to a normal intake of bran, the operation of myotomy appears to have been successful. However, the decrease in the colonic pressure response to food following this procedure persists only if the patients are maintained on a diet supplemented by fiber postoperalively. The alleged diseases of civilizationdiverticular disease, heart disease, gallstones, polyps, hiatus hernia, appendicitis and cancer, in general, have the same geographic distributions.
There
is a marked
decrease
in fiber
in the
diet in these areas, but there is also an increase in fat, protein, and sugar intake. In such areas, when tested, anaerobic bacteria seem to predominate in the feces. It was suggested that anaerobes degrade cholate to deoxycholate, which may act as a cocarcinogen in the colon. The addition of fiber to the diet inhibits degradation of cholate to deoxycholate. Controversy about the “diseases of civilization” and their distribution was spirited. Appendicitis in fact has decreased by 40% in the last 20 years in
the
ischemic
U.S. heart
;
in disease
Finland is quite
the
incidence high,
but
of cancer
of the colon is low; in the Argentine, the population has a high beef and high fiber intake and a high incidence of colon cancer. Multiple etiologic factors undoubtedly are involved. The major problem with epidemiologic evidence is
that
the
changes
in
dietary
practices
with
industrial/economic development tend to be similar wherever they occur; there is a concurrent increase in consumption of animal products, of fat, of sugar, of refined cereals, and the like. When changes in the consumption of two or more materials are highly correlated, the data cannot provide proof as to which of these is related primarily to the disease under investigation. Unless one can find populations in which individual factors are segregated, the epidemiologic
potheses
evidence
which
can
can
then
only
suggest
be subjected
hy-
to study.
Summary It was agreed by the conference that better analytic techniques and better bioassays were needed. Synthetics, duplicating activities though due to natural fiber, were an intriguing alternative for relating a range of fiber effects to the kind of fiber. Bile salt excretion does not seem to be increased by dietary fiber elevation; rather bile salt metabolism seems to be altered, resulting in decreased deoxycholate and increased chenodeoxycholate . Electrical activity, manometric data, and transit studies must be correlated and further studies along these lines should be done in the normal “dirty” colon, to evaluate effects of intraluminal contents. In general, there appears to be a correlation between low fiber intake and the “diseases of civilization,” but nothing definitive can be said about cause and effect as yet. There are inconsistencies in the geographic evidence relating low fiber diets to disease; perhaps we should be looking for clues in these very inconsistencies.
Proceedings tion.
of the conference
are in prepara-
U
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/3/293/4716325 by Boston University user on 13 January 2019
which lowers viscosity and facilitates easy passage with decreased intracolonic pressure. There was general agreement with these ideas in the approach to diverticular disease involving the sigmoid but they do not readily explain diverticula on the right side of the colon, characterized by a large lumen and fluid bowel content. In addition there have been reports
KIRSNER
