Pectin: a Versatile Fiber
Source
By
Lark L.
Burnham, Ph.D.
Animal
Nutrition
Classification
Pectin, which is derived from apples
and citrus fruit, is a highly soluble
fiber. In general, different fiber
sources are classified by their ability
to absorb water. They range from
basically insoluble (high lignin fibers
such as seed hulls) to very soluble
(pectin and other gel-forming fibers).
Solubility is important because it
determines how well the fiber will be
digested by the gastrointestinal tract (GIT)
microflora.
All
mammals lack the enzymes necessary to
digest fiber. They depend on a
synergistic relationship with
microorganisms to degrade it for them.
The by-products of microbial
fermentation of fiber are short-chain
fatty acids, primarily acetic, propionic,
and butyric acids.
Microorganisms require water for
viability and for fermentation. Greater
water absorption by a fiber means more
extensive bacterial degradation or
“digestibility”. Fibers that have a
very low solubility have digestibilities
as low as 3%, while highly soluble
fibers are closer to 60% digestible.
Wheat bran is intermediate, with a
digestibility of around 20%
Microorganisms which ferment fiber are
usually either beneficial or at worst,
benign. Dietary fiber inclusion
promotes the proliferation of these
microorganisms. Their predominance in
the GIT, particularly in the colon, is
directly related to the proportion of
fiber in the diet.
The
role of fiber in nonruminant mammals
Fiber
has both direct and indirect effects of
GIT health. Some of these benefits have
been known for decades, if not
centuries. The most obvious is its
anti-constipation bulking effect.
Pectin, which is generally added in
small amounts of a tablespoon or less,
provides bulk because it swells after
mixing with digesta. It also promotes
the proliferation of beneficial
microorganisms. Because of this latter
property, it can also be categorized as
a “prebiotic”.
Highly
soluble fibers such as pectin have the
additional benefit of stopping
diarrhea. Their ability to quickly
absorb water on contact allows them to
thicken digesta. Pectin only works
while it passes through the GIT, it must
be continually replaced to maintain this
anti-diarrheal effect. It is better to
consume smaller doses of pectin
throughout the day than take the full
dose only once. Pectin treats symptoms;
it does not necessarily address the
cause of the diarrhea.
A less
well-known attribute of fiber is its
ability to trap molecules within its
matrix. These molecules are then
carried through the colon and excreted
in the feces. Two notable substances
have been suggested to be removed by
this process: ammonia/urea (Corley et
al., 1978; Fahey, 1976) and cholesterol.
Nitrogen, which is a by-product of
protein digestion, is generally excreted
as ammonia in the urine. After it is
released from protein, the nitrogen is
absorbed through the GIT membrane as
urea, which is actually two ammonia
molecules stuck together. It then makes
its way to the kidneys for excretion in
the urine.
The
entrapping fiber matrix prevents a
significant amount of ammonia from being
absorbed into the bloodstream, and is
excreted via the feces instead.
Likewise, cholesterol molecules are
trapped within the GIT and excreted in
the feces (Roberfroid and Delzenne.
1995).
Stress
and the gastrointestinal tract
microflora
Stress
has both direct and indirect effects on
the GIT microflora (Tannock, 1983).
Stress-induced hormones can change GIT
pH and cause cessation of active
nutrient movement. Part of the
flight-or-fight mechanism inherent in
all mammals re-directs available energy
to the muscles. This can result in
complete or partial GIT shut down, which
involves both the secretion of enzymes
and nutrient flow. Both pH changes and
cessation of nutrient flow detrimentally
impact indigenous microflora. The
severity of the stress will determine
the extent of the damage.
Another side effect of the reduction in
enzyme activity is the predominance of
highly digestible material that makes
its way into the colon. This situation
can simulate symptoms of exocrine
pancreatic insufficiency (EPI).
Indigenous microflora present both a
physical and chemical barrier and
actively combat pathogens. They are the
first line of defense against pathogens
which enter the host orally. Along with
a healthy immune system, indigenous
microflora prevent the proliferation of
opportunistic pathogens. Antibiotics
can strip the GIT of this protective
barrier.
Potential uses for pectin in medical
practice
Diarrhea
is a very serious and debilitating
condition. If left unchecked, diarrhea
can kill. I have used pectin to control
diarrhea in a variety of mammalian
species, both livestock and pets.
Pectin by itself is not enough to
permanently control diarrhea. The first
victims of this condition are the GIT
microflora. Long-term treatment
involves both the cessation of nutrient
and electrolyte loss, as well as the
replacement of the indigenous
microorganisms. Probiotic
microorganisms temporary fill the
physical and chemical roles performed by
the indigenous microflora. They also
allow these beneficial microorganisms to
proliferate.
Illnesses such as irritable bowel
syndrome (IBS), are marked by chronic
diarrhea. I have used a combination of
pectin and probiotics to control and
reverse this stress-induced disease in
dogs. People and dogs who suffer from
EPI often have chronic diarrhea. This
is a result of highly digestible
material reaching the colon. Normally,
less than 5% of these food components
survive passage of the small intestine
Highly digestible material selects for
colon microflora which cause diarrhea
and may be detrimental to the host in
other ways.
Additionally, conditions that promote
the development or urinary calculi are
ameliorated by the entrapment ability of
fiber in general, and pectin in
particular. The entrapment quality of a
fiber is enhanced by its degree of
solubility.
In
addition, recent research (Ou Limm, et
al., 1997) suggests that pectin may trap
the immunoglobulin responsible for
triggering allergy symptoms (IgE).
Animal trials at Natur’s Way, Inc. show
that most dogs show reduced allergy
symptoms when fed a pectin-based
probiotic.
Because pectin absorbs moisture very
quickly, it swells. If this swelling
occurs in the esophagus, it can trigger
regurgitation. Dogs should be fed pectin
in the dry form, either on dry food or
on a dry treat.
Pectin
is inert to the host, it has no side
effects and remains within the confines
of the GIT. It needs to be replenished
on a daily basis to provide continuous
benefit. Pectin combined with a daily
probiotic supplement will encourage GIT
health. Complicating conditions such as
IBS and EPI will determine the probiotic
concentration employed.
MSE
Natural Defense is a hypoallergenic
pectin-based probiotic supplement for
pets. It is made from food-grade pectin
and pure microbial cultures (3.0 x 108
cfu/g).
References
cited
Corley, J. R, R. A. Easter, M. A. Roos
and G. C. Fahey. 1978. Effect of
various fiber sources on gain, feed
efficiency and nitrogen retention in the
weanling pig. Nutr. Rep. Internat’l
18:135.
Fahey,
G. C. 1976. Factors influencing the
utilization and digestibility of
hemicellulose. Doctoral dissertation,
West Virginia University, Morgantown.
Beong
Ou Lim,
Koji Yamada,
Michiko Nonaka,
Yuichiro Kuramoto,
Pham Hung,
and
Michihiro Sugano.
1997. Dietary Fibers
Modulate Indices of Intestinal Immune
Function in Rats. J. Nutrition 663-667
Roberfroid and N. Delzenne. 1995.
Oligofructose supplemented diet lowers
serum and VLDL concentrations,
triglycerides, phospholipids and
cholesterol in rats. Lipids 163-167.
Tannock, G. W. 1983. Effect of
dietary and environmental stress on the
gastrointestinal microbiota. In: Human
intestinal microflora in health and
disease (Hertges, D. J., ed.), pp. 517 –
539, Academic Press, New York, NY
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