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).  It is available either directly from Natur s Way, Inc. (800-615-0299) or on amazon.com.  Free samples are available upon request (lark@carsoncomm.com).

 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