INTESTINAL PARASITES, BACTERIAL DYSBIOSIS AND LEAKY GUT
FROM POWER HEALING (RANDOM HOUSE, 1998)
The human intestine maintains within its inner cavity a complex, crowded environment of food remnants and microbial organisms (called "the intestinal flora") from which the body derives nourishment and against which the body must be protected. The relationship between the human host and her army of microbes is described by the Greek word, symbiosis, which means "living together". When symbiosis benefits both parties, it is called mutualism. When symbiosis becomes harmful, it is called dysbiosis. The first line of protection against dysbiosis and intestinal toxicity is strict control of intestinal permeability, the ability of the gut to allow some substances to pass through its walls while denying access to others. The healthy gut selectively absorbs nutrients and seals out those components of the normal internal milieu which are most likely to cause harm, except for a small sampling which it uses to educate and strengthen its mechanisms of immunity and detoxification.
Bacteria form the largest segment of the intestinal flora. The number of bacteria in the large bowel (about a hundred trillion) exceeds the number of cells in the human body. Intestinal bacteria perform some useful functions, so that our relationship with them is normally one of mutual benefit. They synthesize half a dozen vitamins, supplementing those which are obtained from food. They convert dietary fibre--that part of food which humans cannot digest--into small fatty acids which nourish the cells of the large intestine. They degrade dietary toxins like methyl mercury making them less harmful to the body. They crowd out pathogenic bacteria like Salmonella, decreasing the risk of food poisoning. They stimulate the development of a vigorous immune response. Four-fifths of the body's immune system is located in the lining of the small intestine.
Bacteria are dangerous tenants, however, so that dysbiosis is a common problem. As powerful chemical factories, bacteria not only make vitamins and destroy toxins, but also destroy vitamins and make toxins. Bacterial enzymes can inactivate human digestive enzymes and convert human bile or components of food into chemicals which promote the development of cancer. Some by-products of bacterial enzyme activity, like ammonia, hinder normal brain function. When absorbed into the body, they must be removed by the liver. People whose livers fail this task, because of conditions like cirrhosis, develop progressive neurologic dysfunction resulting in coma and death. For them, the administration of antibiotics which slow the production of nerve toxins by intestinal bacteria can be life saving.
The immune reactions provoked by normal intestinal bacteria may be harmful rather than helpful. Inflammatory diseases of the bowel, including ulcerative colitis and Crohn's disease (ileitis), and several types of arthritis have been linked to aberrant immune responses provoked by intestinal bacteria. Two types of aberrancy have been described. First, intestinal bacteria contain proteins which look to the immune system very much like human proteins; they confuse the immune system and may fool the body into attacking itself. Second, fragments of dead bacteria may leak into the wall of the intestine or into the blood stream due to a breakdown in the mechanisms which regulate intestinal permeability. Circulating through the body, bacterial debris is deposited in tissues such as joints, provoking an attack on those tissues by an immune system trying to remove the foreign material.
Bacterial colonies in the human intestine co-exist with colonies of yeasts, which are no less dangerous, just far fewer in number. Bacterial colonization prevents yeasts from expanding their niche. Frequent or prolonged use of antibiotics decimates bacterial colonies, removing the natural brake on yeast growth. The most obvious effects of yeast overgrowth are local infections, like vaginitis, produced when yeast invade and disrupt cells which line the body's surface. Intestinal yeast infections can cause chronic diarrhea, although most gastroenterologists fail to recognize this. Yeast can also provoke allergic reactions, precipitating asthma, hives, psoriasis or abdominal pain. The occurrence of allergic symptoms or the aggravation of a pre-existing allergy which follows the use of antibiotics should always prompt an investigation into yeast overgrowth as a potential trigger. Neglect of this factor by allergists has left countless patients trapped in a spiral of increasing allergic reactivity, augmented each time antibiotics are prescribed.
In addition to bacteria and yeast, most of the world's four billion people are also colonized by intestinal parasites. Contrary to popular belief, parasitic infection is not unusual in the U.S. population. It is a common ocurrence, even among those who have never left the country.
Unlike bacteria, parasites appear to serve no useful function. The part of the immune system which they stimulate does not strengthen the organism to resist serious infection; instead it contributes to allergic reactions, so that parasitic infection increases allergic tendencies. There are two general groups of parasites. The first consists of worms--tapeworms and roundworms--which attach themselves to the lining of the small intestine, causing internal bleeding and loss of nutrients. People infested with worms may have no symptoms or may slowly become anemic. The second category is the protozoa, one-celled organisms like the amoeba which caused John Gerard's colitis. The first protozoa were discovered over three hundred years ago by Antonie van Leeuwenhoek, the most famous of the early microscopists. When the inquisitive Dutchman set about to examine everything in the world that would fit under the lens of a microscope, he found organisms in his own stool that closely match the description later given to Giardia lamblia.
Giardia is the major cause of day-care diarrhea. Twenty to thirty per cent of workers in day care centers harbor Giardia. Most have no symptoms; they are merely carriers. A study at Johns Hopkins medical school a few years ago demonstrated antibodies against Giardia in twenty per cent of randomly chosen blood samples from patients in the hospital. This means that at least twenty per cent of these patients had been infected with Giardia at some time in their lives and had mounted an immune response against the parasite.
In 1990 I presented a paper before the American College of Gastroenterology which demonstrated Giardia infection in about half of a group of two hundred patients with chronic diarrhea, constipation, abdominal pain and bloating. Most of these patients had been told they had irritable bowel syndrome, which is commonly referred to as "nervous stomach". I reached two conclusions from this study: (1) Parasitic infection is a common event among patients with chronic gastrointestinal symptoms. (2) Many people are given a diagnosis of irritable bowel syndrome without a thorough evaluation. My presentation was reported by numerous magazines and newspapers, including the New York Times. My office was flooded with hundreds of phone calls from people who were suffering with chronic gastrointestinal complaints. Most of them had been given a diagnosis of Irritable Bowel Syndrome (IBS) by their physicians. The standard treatment for this syndrome had not helped them. All they had received was a label. Many had been told there was no cure. In evaluating these patients, I found that the majority had intestinal parasites, food intolerance or a lack of healthy intestinal bacteria. These conditions were not mutually exclusive. Many patients had more than one reason for chronic gastrointestinal problems. Treating these abnormalities as they occurred in various patients produced remarkably good therapeutic results. A year later, researchers in the Department of Family Medicine at Baylor University in Houston reported findings similar to mine.
Giardia contaminates streams and lakes throughout North America and has caused epidemics of diarrheal disease in several small cities by contaminating their drinking water. One epidemic, in Placerville, California, was followed by an epidemic of Chronic Fatigue Syndrome, which swept through the town's residents at the time of the Giardia epidemic. Possibly, this epidemic was due to failure of some people to eradicate the parasite. In 1991, my colleagues and I published a study of 96 patients with chronic fatigue and demonstrated active Giardia infection in 46 per cent.
Sometimes, the intestinal damage produced by giardiasis persists for months after the parasite has been successfully treated. The impairment of digestion and absorption which results from this damage may cause fatigue and other symptoms.
When I first began presenting the results of my clinical research on parasitic infection, in the mid-1980's, my reports were met with considerable skepticism. The present decade has witnessed an increased awareness of parasitic infection as a common public health problem in the United States, thanks largely to Cryptosporidium, which recently achieved notoriety for contaminating Milwaukee's water supply, causing the largest epidemic of diarrhea in U.S. history, infecting 400,000 people and causing over one hundred deaths. Most municipal water supplies in the U.S. today are home to protozoa like Giardia and Cryptosporidium and one in five Americans drinks water that violates federal health standards. Every year, almost a million North Americans become sick from water-borne diseases; about one per cent die. Further epidemics are inevitable. A recent epidemic occurred in Clark County, Nevada, despite state-of-the-art municipal water treatment.
How protozoa make people sick is not clear. Some directly invade the lining of the intestine, others provoke an allergic reaction that causes the damage. It appears certain that humans coexist quite readily with their parasites as long as the barrier formed by the intestinal lining remains fully intact, so that the parasites cannot attach to the wall of the bowel. Millions of people throughout the world are carriers of E. histolytica; the organism can be found in stool samples but it does not seem to make them ill. The variability of pathogenic potential recalls Pasteur's challenge to the French Academy: do the causes of disease lie within the microbe or do they lie within the host? When the attachment of a parasite initiates a series of injuries to the intestinal wall that increase its permeability, it generates a cascade of reactions that can shatter a person's health in many different ways. Excessive permeability permits excess absorption of antigens and microbial fragments from the gut, over-stimulating the immune response, fostering allergy and auto-immunity.
Excess permeability also allows excessive absorption of toxins derived from the chemical activity of intestinal bacteria, stressing the liver. All materials absorbed from the intestine must pass through the liver before entering the body's general circulation. Here, in the cells of the liver, toxic chemicals are destroyed or else prepared for excretion out of the body. The cost of detoxification is high; free radicals are generated and the liver's stores of anti-oxidants are depleted. The liver may be damaged by the products of its own attempts at detoxification. Damage may extend to the pancreas. Free radicals are excreted into bile; this "toxic" bile flows into the small intestine and can ascend into the ducts which carry pancreatic juices, damaging the pancreas, aggravating malnutrition.
The symptoms produced by excessive intestinal permeability may be limited to the abdomen or may involve the entire body. They may include fatigue and malaise, joint and muscle pain, headache and skin eruptions. The clinical disorders associated with increased intestinal permeability include any inflammation of the large or small intestine (colitis and enteritis), chronic arthritis , skin conditions like acne, eczema, hives or psoriasis, migraine headaches, chronic fatigue, deficient pancreatic function and AIDS . In most cases, it is incorrect to think of excessive permeability as the cause of these disorders. Instead, excess permeability occurs as part of the chain of events which causes disease and aggravates existing symptoms or produces new ones.
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