The Ins and Outs of Natural Digestion

by Steve Myers

Socrates once said: “Worthless people live only to eat and drink; people of worth eat and drink only to live.” People can debate which is better, but either way, what they eat and drink shapes who they are, in more ways than one. The fuel for life’s tangible tasks comes from what is digested, rendering one’s digestive health not only important for longevity, but also for quality of life. In the face of aging, a nutrient- depleted processed food supply, hectic modern lifestyles, and widespread digestive disorder and disease, a handful of substances derived from nature possess a wealth of digestive health potential and can help make life worth enjoying.

In its simplest description, digestion involves the handling of consumed food or drink that travels through the stomach and intestines, where the body takes what it wants, before excreting what’s left over. But far be it for life to operate without obstacles; nutrients face many perils along their journey to absorption. From stomach bile to harmful gut bacteria, the digestive system can be a harsh environment where any number of things could go wrong.

The large and small intestines, also called the guts, are home to a bacterial smorgasbord that can be either beneficial or harmful. These microbes can produce enzymes that can break down otherwise indigestible food particles, such as cellulose and other carbohydrates, resulting in fatty acids, lactic acid, methane, hydrogen and carbon dioxide.

Ever the humorist, Twain might have been truer in his day. His statement hints at the infancy of nutrition and digestive knowledge, as foods consumed back then were certainly not as processed as they are today. “Food is dead,” quipped Jon Barron, director of the Baseline of Health Foundation, who contended most Americans are “digging their graves one forkful at a time.” He noted the body can not build healthy cells on a diet of pizza, beer and other junk foods.

“With the increase in unhealthy diets and hectic lifestyles, people are experiencing more digestive problems than ever before,” said Lynn Greaves, vice president of Enzymes Inc., adding that the pharmaceutical industry has, unfortunately, focused digestive awareness on a malfunctioning body instead of poor diet and food quality, offering merely to relieve symptoms.

Herb Joiner-Bey, M.D., a practicing physician, noted America is rife with poor diets. “It is unfortunate that the health food industry only serves 10 percent of the U.S. population,” he lamented. “[Americans] fail to consume enough pure water and whole organic plant foods rich in natural fiber and micronutrients that would support optimal digestive health naturally. There is much that the average American needs to learn and implement in order to improve digestive well-being.”

Greaves emphasized the first step in digestive education is to realize the impact of a poor diet riddled with processed foods. “When the body is forced to produce all of the enzymes to digest the food consumed, at some point it will not be able to produce enough for complete digestion resulting in indigestion, bloating, constipation, etc.,” she said.

Various glands produce more than 20 digestive enzymes in the mouth, stomach and intestines. The stomach glands produce gastric enzymes, including peptidase (for proteins), gelatinase (for gelatin/collagen from meats) and gastric lipase (for tributyrin,a butter fat). Meanwhile, the pancreas is responsible for secreting numerous proteases and amylases, including trypsin (a peptidase), pancreatic amylase (for starch and glycogen) and several elastases (for protein elastin). Then, the epithelium in the small intestines creates many peptidases as well as the more well known amalyases that break disaccharides into monosaccharides—sucrase (for sucrose and glucose), lactase (for lactose) and maltase (for maltose).

However, many of the enzymes needed to digest foods come from the foods themselves, especially in the case of plants, namely vegetable and fruits. For instance, pectinase from the cell walls of plants helps degrade pectin. Still other enzymes are produced by bacteria— phytase helps denature phytic acid found in grains and seeds; cellulase breaks down otherwise indigestible fibers common to plant cell walls.

Unfortunately, enzymes are sensitive to their environments. As proteins, enzymes are denatured from heat exposure. They are also affected by pH level, which can change the shape of an enzyme, although the optimum pH level is not the same for each enzyme.

“The enzymes produced in the pancreas are only active within a fairly narrow pH range,” advised Nena Dockery, technical services manager for National Enzyme Co. (NEC), noting enzyme supplements derived from animal sources are usually entericcoated or over-formulated to compensate for loss in the acidic gastric region. “Plant and microbial enzymes have a much broader pH range and can retain activity throughout the entire gastrointestinal tract.”

Supplementing the diet with enzymes can be tricky due to the source of the various enzymes. Enzymes derived from animals—usually pigs and cows—have a long history of use, but would not be an option for vegetarians. Dockery reported the enzymatic activity of these animal enzymes is limited compared to those from plants or microbes. “Microbial enzymes offer a wide range of enzymatic activity,” she said.

According to Greaves, most “vegetarian” enzymes are from microbes, not from plants—which primarily provide papain and bromelain from papaya and pineapple, respectively. “Vegetarian enzyme supplements usually provide a broader spectrum of digestive enzymes that act on all of the main food components (protein, carbohydrates, fat and fiber),” she said. “Whereas animal enzymes focus predominantly on digesting proteins, with minimal (pancreatin) or no (pepsin, trypsin and chymotrypsin) carbohydrate or fatdigesting activity.” She also noted both bromelain and papain focus entirely on protein, offering no assistance with carbohydrate, fat and fiber digestion.

Faced with an overwhelming number of enzymes from many sources, each with its pros and cons, retailers and consumers may well be confused as to which ones and how many different kinds are ideal to take. Greaves touted the benefits of taking a digestive enzyme supplement containing a proper balance of a variety of enzymes. “The digestion of food is a relatively complex process requiring many different enzymes,” she said. Mairi Ross, senior product developer at Sedona Labs, also supported broadspectrum enzyme supplementation. “What many people do not realize is that they need enzymes for the small intestine as well as the stomach,” she noted, confirming an enzyme needs to be enteric-coated to survive stomach acid and make it to the small intestines. Dockery agreed: “Utilizing a wide variety of enzymes has some definite advantages, because it is not always easy to isolate a deficiency in a particular enzyme.”

A 2004 animal trial found multienzyme combinations improved digestibility and nutrient utilization,¹ and was confirmed by other studies showing enzyme combinations can affect nutrient bioavailability, weight gain and overall growth.^2,3,4 Human trial results have also suggested digestive benefits from enzyme supplementation. The American Institute for Biosocial and Medical Research (AIBMR), Tacoma, Wash., study in male cyclists showed a patented amylase enzyme (as Carbogen®, from Triarco Industries) improved carbohydrate metabolism and increased resulting glucose assimilation.⁵ A joint study by NEC and the Dutch firm TNO Nutrition and Food Research revealed a fungal enzyme formula—containing amylase, protease and lipase enzymes— significantly increased carbohydrate digestion—with only slight improvements to protein digestion—in the small intestine.⁶

Focusing on a single macronutrient, supplemental lipase has been shown to reduce bloating and gassiness in subjects fed high-fat cookies.⁷ Research has also demonstrated bromelain helps prevent diarrhea by inhibiting secretion of various toxins and pro-inflammatory mechanisms.⁸

Some enzymes, such as lactase, are produced by probiotics, which work in conjunction with enzymes in the digestive system. As beneficial bacteria, probiotics work mainly in the gut, where they help maintain a balance of more than 400 strains of healthy and harmful bacteria.

Ross noted many Americans with digestive problems have been taking antacids, acid blockers and laxatives for years, yet they still suffer from these maladies. “They are beginning to understand that healthy alternatives like enzymes and probiotics do more than just temporarily reduce the symptoms,” she said.“Natural solutions actually address the source of the problem to support a truly healthy digestive system.”

The lion’s share of probiotic activity involves blocking potentially harmful bacteria from receptor sites along the intestinal wall. “Bacteria compete with each other,” confirmed Michael Shahani, director of operations for Nebraska Cultures. This competition can have marvelous results, as probiotics have proven effective in alleviating numerous digestive illnesses, including diarrhea, constipation, irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBDs).^9,10

Discomforting in the short term and potentially dangerous in the long-term, diarrhea occurs when water is insufficiently absorbed in the large intestine; it manifests as runny stool, too-frequent bowel movements, abdominal pain, vomiting and dehydration. Diarrhea can be caused by viral or bacterial infections, and possibly by an enzyme deficiency (i.e. lactose intolerance). Probiotics can complement rehydration therapy used to treat infectious diarrhea.^11,12 However, antibiotics used to treat infections can cause chronic diarrhea; probiotic supplementation can help those on such medications.¹³ In fact, a 2006 trial showed probiotics—including Lactobacillus GG, S. boulardii, B. lactis and S. thermophillus—reduce the risk of antibiotic-associated diarrhea (AAD) in children. “For every seven patients who would develop diarrhea while being treated with antibiotics, one fewer will develop AAD if also receiving probiotics,” concluded scientists from the Medical University of Warsaw, Poland.

Children are at increased risk of diarrhea, especially if living in an underdeveloped area with an unsafe drinking water supply. According to the World Health Organization (WHO), millions of children die each year from chronic diarrhea in Third World countries. While improved conditions could reduce diarrhea among children, probiotics have also shown promise. In fact, infants on formula fortified with B. lactis and L. reuteri had a lower incidence and severity of diarrhea.^14,15 However, other trials have produced mixed results. In a French study, probiotic-fortified infant formula failed to decrease incidence of diarrhea, but did decrease the severity;¹⁶ while an Indian trial found L. casei ST11 strain inhibited nonrotoviral diarrhea in children, but had no effect on rotoviral diarrhea.¹⁷ More recently, a 2005 study from the Washington University School of Medicine, St. Louis, reported administration of Lactobacillus GG for 30 days in African toddlers had no effect on intestinal integrity.¹⁸

Diarrhea is also indicated in irritable bowel syndrome (IBS), a functional disease or disorder attributed to a malfunction between the gut, brain and nervous system, instead of to a structural or biochemical cause. Inflicting as much as 20 percent of the population and the most commonly diagnosed gastroenterological illness, IBS is marked by abdominal pain or discomfort from a group of symptoms such as loose or more frequent bowel movements, diarrhea, and/or constipation.

In mid-2006, University of Manchester, England, scientists reported Bifantis (as Bifidobacterium infantis 35624, from P&G Health) may relieve IBS symptoms such as diarrhea and constipation.¹⁹ Female IBS patients taking freeze-dried, encapsulated Bifantis once daily for four weeks showed significantly superior results in reducing abdominal pain, bloating, bowel dysfunction, incomplete evacuation, straining and passage of gas; no adverse events were reported. The scientists noted the optimal dosage appeared to be 100 million cfu (colony forming units).

Japanese researchers showed a probiotic combination reduced pain and bloating, and normalized bowel movements associated with IBS.²⁰ Mayo Clinic researchers also reported a combination probiotic supplement (containing 450 billion live lactic acid bacteria) alleviated bloating and pain in patients with diarrhea-marked IBS;²¹ they noted the benefit was unrelated to an alteration in gastrointestinal or colonic transit, but their subsequent trial revealed the probiotics reduced flatulence scores and retarded colonic transit.²² In Irish research, L. salivarius and Bifantis administration outperformed pharmaceutical treatments in alleviating symptoms of IBS, including abdominal pain, bloating and bowel movement difficulty.²³ The investigators noted Bifantis actions were comparable to IBS drugs Zelnorm and Lotronex.

Against constipation alone, a probiotic beverage containing L. casei reduced the severity of constipation and stool consistency in German patients with chronic constipation,²⁴ although other studies have questioned or dispelled the benefit of various lactobacilli on constipation.²⁵

Many of the same symptoms seen in IBS are also apparent in IBDs, including ulcerative colitis (UC) and Crohn’s disease. UC is a chronic disorder manifested as inflammation and ulceration of the colon mucosa, or innermost lining. This can cause the colon to empty frequently, resulting in diarrhea and abdominal pain. In Crohn’s, inflammation generated by an autoimmune response can strike any area of the GI tract, although it commonly affects the small intestines and the colon. About 500,000 Americans suffer from this chronic disease, which can result in abdominal pain/cramps, fever and, at times, rectal bleeding.

Probiotic supplementation appears to effectively address many parameters of IBD development, progression and remission.^26,27 As the theory goes, probiotics inhibit pathogenic bacteria from colonizing in the gut, also protecting the gut barrier.^28,29 A 2005 Spanish trial confirmed these mechanisms of action;³⁰ however, an animal study conducted at the Gaylor School of Medicine,Waco, Texas, and M.I.T., Boston, added to the theory, reporting a combination of L. reuteri and L. casei decreased pro-inflammatory cytokines.³¹ University of Chicago scientists further noted probiotics inhibit inflammatory cytokine NFkappaB, while also inducing the expression of cytoprotective heat shock proteins in intestinal epithelial cells.³²

On symptoms and progression of UC, various lactobacilli and bifido bacteria can help maintain intestinal integrity, curb inflammation and reduce scores indicating disease activity, endoscopy and histology.^33,34,35 Other research demonstrated bifido probiotics administered to Chinese UC patients can reduce flare-ups, compared to standard drug treatment with sulphasalazine and glucocorticoids.³⁶

These probiotics have also proven useful against pouchitis, another IBD related to UC. In a Norwegian study, patients given milk fermented with both lactobacilli and bifido bacteria prior to pouchitis surgery experienced reduced symptoms and post-surgical endoscopic activity.³⁷ And single strain supplementation with Lactobacillus GG in Dutch UC patients prior to surgery delayed the development of postoperative pouchitis.³⁸

In the management of UC, probiotics have been effective in tandem with prebiotics; together they are called synbiotics.

In a trial conducted at the University of Dundee, England, bifidobacteria combined with prebiotic (as Synergy 1® inulin-ogliofructose, from Orafti) were administered for one month to active UC patients, who were then monitored for gut bacteria levels and inflammation.³⁹ Those taking the probiotic-prebiotic combination displayed decreased inflammation and related cytokines, and exhibited gut epithelial tissue regeneration.

Even bacteria need to eat, which is where prebiotics come in. Bacteria feed on these indigestible oligosaccharide chains in the gut. Prebiotics—fructooligosaccharides (FOS), inulin, arabinogalactans and lactulose—are found naturally in plants and can be, in some cases, produced enzymatically from sugar. They pass through the stomach and are fermented by gut microflora, selectively stimulating the growth and activities of the bacteria.⁴⁰ In addition to enhancing the benefits of probiotics, prebiotics can also improve absorption of minerals, including calcium and magnesium.

Inulin is a short-chain glucoseterminated fructose, also called oligosaccharide when hydrolyzed; while the long-chain polysaccharide FOS can improve immune function and the absorption of nutrients, particularly minerals.⁴¹ In recent research, a trial testing inulin from chicory (as Oliggo-Fiber®, from Cargill) in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME) resulted in stimulation of intestinal bacteria, namely bifidobacteria.⁴² Inulin has also displayed specific benefits to digestive illness, including alleviating diarrhea.⁴³ Similarly, FOS combined with L. sprogenes has been shown to significantly reduce duration of antibiotic-induced diarrhea in children.⁴⁴ On its own, FOS (as NutraFlora®, from GTC Nutrition) reduced intestinal inflammation in a animal colitis model by increasing intestinal lactic acid bacteria.⁴⁵

“When comparing prebiotics, the glucose terminals and short-chain length are extremely important to the fermentation profile and ingredient functionality,” said Coni Francis, Ph.D., scientific affairs manager for GTC Nutrition. “The chemical structure and relative chain length of a prebiotic will determine how easily it can be used by probiotic bacteria.”

Arabinogalatans (AG) are longchain, soluble prebiotic fibers derived from trees of the genus Larix (Larch).“Due to the slower fermentation, digestive tolerance is high,” said Bryan Rodriguez, technical marketing & scientific affairs manager for Lonza Inc. “As a result of fermentation, the beneficial microflora (probiotics) such as Bifidobacteria and lactobacilli increase.” Case in point: a 2001 University of Minnesota trial found six weeks of larch AG supplementation increased total intestinal microflora, with the most pronounced growth in lactobacilli.⁴⁶

Dietary fibers, including prebiotics,are essential to healthy digestion, as soluble fiber can improve stool bulk and constipation, alleviating the need for laxatives.⁴⁷ “It has been estimated that many Americans get as little as 10 g of dietary fiber daily,while the worldwide average is 50 to 75 g/d,” Joiner- Bey noted. “Some nutritionists would advocate as much as 100 g/d.”

In addition to prebiotic properties, acacia gum fiber can improve water absorption and limited potassium loss associated with diarrhea;⁴⁸ it also improves small intestine function, inhibiting nitric oxide synthase (NOS) and improving nutrient absorption.⁴⁹ Other research findings show acacia gum and psyllium fiber can help people suffering incontinence, as the fibers are completely fermented in the colon and can reduce incontinent stool.⁵⁰ “Psyllium can effectively alleviate constipation and non-specific diarrhea,” added Bill Steiber, vice president of medical affairs at Konsyl Pharmaceuticals. “It also promotes the growth of ‘good’ bacteria in the colon.”

It isn’t just the amount, but which kind of fiber is consumed. Soluble fiber (celluloses, some hemicelluloses, insoluble pectins and lignins) dissolves in water, is partially degraded by gut microbes and serves as “bulking agents” that help bowel elimination and decrease transit time. Insoluble fiber (gums, beta-glucans, soluble hemicelluloses and pectins) does not dissolve in water and is almost fully degraded by intestinal bacteria; it increases fecal weight via bacterial proliferation, delays gastric emptying, increases satiety, and decreases blood cholesterol, glucose and insulin.

Joiner-Bey suggested ground flaxseed is a good source of both soluble and insoluble fiber. He added: “In fact, knowledgeable experts on natural approaches to bowel disorders are turning to ground flaxseed as a preferred fiber source due to fewer long-term problems compared to psyllium.”

Unfortunately, many Americans turn to over-the-counter (OTC) medications such as antacids and laxatives. “The appeal of stimulant laxatives is that they provide quick relief, typically in six to 12 hours; however, they also irritate the lining of the colon as a mechanism to move material out of the colon quickly,” Steiber explained. “Long-term use is not recommended.”

People with digestive disorders are at a greater risk of losing valuable nutrients. One of the most common nutrient deficiencies attributed to digestive illness is zinc, which is especially depleted from diarrhea.⁵¹ Zinc has augmented rehydration therapy by reducing stool output and illness duration in children with acute diarrhea;⁵² and it has been heralded as standard treatment in Third World countries for its ability to decrease incidence of diarrhea.⁵³

In other digestive ailments, Crohn’s patients also exhibit low zinc absorption and corresponding zinc levels.⁵⁴ Fortunately, zinc sulfate supplements can improve intestinal barrier function and lower the risk of Crohn’s relapse. And, researchers have found IBS patients have low intakes of zinc, as well as calcium, magnesium and fiber.⁵⁵ A chelate of zinc and carnosine (as PepZin GI, from Lonza) can improve mucosal health,⁵⁶ as well as suppress the activities of H. pylori, curbing both ulcers and intestinal inflammation, according to researchers.^57,58

Other nutrients important to people with digestive disorders include folate, which is often deficient in Crohn’s patients,⁵⁹ as is selenium,which can work on oxidative components of IBDs.⁶⁰ Combined with selenium, vitamin E can also address oxidative activity and reduce the severity of colonic lesions associated with colitis.⁶¹

Taking an herbal approach to digestive health, aloe supports digestion by protecting mucosa from stomach acid.⁶² This calming herb also targets IBDs by curtailing inflammatory cytokines and reactive oxygen species (ROS).⁶³ Researchers have concluded UC patients respond well to aloe treatment, with decreased histological disease activity and no side effects.⁶⁴

Peppermint also supports a healthy digestive system, as research shows it quells spasms in the esophagus, stomach and intestines,^65,66 suggesting the herb is a viable remedy for IBS. Judy Haswell, president of Alta Health Products, said people suffering from digestive disorders have used the company’s Can-Gest herbal blend— including peppermint, mallow, marigold and orange tree leaf—for both specific and general digestive support.

Considering the state of digestive health in America and the potential benefits of numerous dietary supplements, consumer interest in natural support for digestion is strong. “Although perhaps not as familiar to the average consumer, natural digestive aids have also gained in popularity and the market continues to grow,” Greaves said. Joiner-Bey agreed, adding: “The popularity of digestive enzymes, HCl, fiber products, and other digestive aids should continue to do well, as the Baby Boomer generation ages and needs more help with declining digestive efficiency.”

To view the references for this story, click here.

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