What's Living in Your Digestive System

If you think intestinal parasites only lead to gut disturbances such as upset stomach and diarrhea, think again. Because problems that happen in your stomach don't stay in your stomach.
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If you think intestinal parasites only lead to gut disturbances such as upset stomach and diarrhea, think again. Because problems that happen in your stomach don't stay in your stomach.

I revealed how two common intestinal parasites can cause mystery illnesses; Giardia with chronic fatigue and Cryptosporidium, with diarrhea, in my earlier post Intestinal Parasites May Be Causing Your Energy Slump.

But there are many other surprising effects of intestinal parasitic infection that often occur outside your digestive system.

These effects are primarily due to allergic and autoimmune reactions provoked by the parasites and include:

•Uveitis (inflammation of the interior of the eye)
•Blood clots caused by antiphospholipid antibodies
•Paralysis (Guillain-Barre syndrome)

One of the most common effects of intestinal parasites is food allergy. I looked at the effects of parasitic infection among patients in my medical practice. For people with multiple food allergies who were found to have intestinal parasites, treatment of the parasitic infection produced a dramatic reduction in food allergy in about half the cases. It's my belief that anyone with food intolerance or allergy should be tested for intestinal parasites.

Unsuspected Cause of Chronic Illness

Parasites may cause allergic or autoimmune disorders in two ways.

First, the inflammation caused by an intestinal infection can cause an increase in the permeability of the small intestine, a phenomenon known colloquially as "leaky gut". Uncover more about this often undiagnosed condition in my article: Do You Have Leaky Gut Syndrome?

Second, over two-thirds of your body's immune system is located in the wall of the small intestine. The immune cells (called lymphocytes) leave the intestine and travel all over your body. When activated by a parasitic infection, they can carry the inflammatory message to your joints, your skin, your eyes, and your lungs.

Parasites Are A Worldwide Problem

Contrary to popular belief, parasitic infection is not unusual for people living in the U.S. Americans get parasites all the time, even people who have never left the country. With the prevalence of parasites around the world, staying clear of them can be a challenge:

  • Entamoeba histolytica infects 10 percent of the world's population.
  • Amoebic cysts can be found in stool samples of 2 percent to over 40 percent of individuals, depending on the area and level of hygiene and sanitation
  • Over 90 percent of individuals infected with Entamoeba histolytica are asymptomatic. Asymptomatic carriers may spread infection to others who then develop symptoms.

Parasites and Rheumatoid Arthritis (RA).

Chronic Entamoeba histolytica infection of humans has been associated with autoimmune phenomena such as rheumatoid arthritis (RA). Research suggests that an excessive and prolonged antibody response to Entamoeba histolytica or other enteric organisms may contribute to joint inflammation in RA.

In one example, I had a patient with rheumatoid-like arthritis whose arthritis went into rapid and complete remission upon treatment of G. lamblia infection with metronidazole. Relapse occurred when the patient acquired Entamoeba histolytica during a trip to Egypt; remission occurred slowly following treatment of amoebiasis.

Long duration of symptoms and the presence of chronic constipation do not rule out protozoan infection.

Chronic giardiasis, responsive to antimicrobial therapy, is as often characterized by constipation as by diarrhea. I've encountered patients in whom severe gastrointestinal symptoms present for as long as 20 years has totally cleared upon treatment of giardiasis or amebiasis. Initial treatment options include a number of anti-protozoan drugs and herbs.

For information on finding and treating parasites, including a look at herbal remedies, read my article Fighting Parasites

When I lecture on this topic, I often give the audience an idea of just how large the digestive system really is by indicating that it would take up the size of a tennis court if it were spread out on a flat surface.

So here is a quick tour of what lives in the human gut, the good and the bad, and a few problem areas.

What's Living in Your Digestive System

One of the most toxic environments to which people are exposed is within their own gastrointestinal tract. From the mouth to the anus, every inch is colonized by bacteria. The alimentary canal is basically an external surface internalized within the human body. It remains in contact with the external environment.

The gastrointestinal tract is a complex and dangerous frontier.
All the nutrients required for life must pass through, while the bad guys are kept out. Given the large area, there is much that can go wrong, leading to a huge range of ailments. In keeping with its immense surface area and intense exposure to foreign antigens, the intestinal tract is the largest organ of immune surveillance and response in the human body.

The Bacteria Within
There are over 500 species of bacteria that live in the healthy human alimentary canal; in the average adult they weigh about one kilogram. There are trillions of bacteria throwing a party in your gut right now, and the fact is you are better off for it. Let's face it, bacteria have been around longer than humans, and have been with us since the beginning.

In a healthy gut, friendly bacteria are busy helping you out in a variety of important ways.

Billions of Bacteria Lend a Helping Hand
The normal healthy bacteria help to generate energy from the food we eat. Bacteria synthesize at least seven essential nutrients, supplementing dietary intake of folic acid, biotin, pantothenic acid, riboflavin, pyridoxine, cobalamin and vitamin K. Bacteria also participate in the metabolism of drugs, hormones and toxins.

By demethylating methyl mercury, gut flora protect mice from mercury toxicity. They prevent potential pathogens from establishing infection by numerous mechanisms. Bacteria can help crowd out pathogenic bacteria like Salmonella, decreasing the risk of food poisoning.

For a detailed explanation of healthy bacteria, check out: Probiotics or Friendly Bacteria.

But Medicines Can Interfere with Bacteria
Alteration in the level of normal flora by antibiotics has long been known to allow secondary infection by pathogenic bacteria and yeasts.

Bacteria Gone Bad
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. Learn more about how the liver detoxifies the body in my article: Why You Need to Detoxify 24 Hours a Day

Now I'd like to hear from you...

Did you experience any stomach upset or other complaints?

What about food allergy?

Have you taken anything for it, and what helps?

Please let me know your thoughts by posting a comment below.

Best Health,

Leo Galland, M.D.

Help Fight Parasites by forwarding this article to your friends and family and sharing on Facebook.

Leo Galland, M.D. is a board-certified internist, author and internationally recognized leader in integrated medicine. Dr. Galland is the founder of Pill Advised, a web application for learning about medications, supplements and food. Sign up for FREE to discover how your medications and vitamins interact. Watch his videos on YouTube and join the Pill Advised Facebook page.


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This information is provided for general educational purposes only and is not intended to constitute (i) medical advice or counseling, (ii) the practice of medicine or the provision of health care diagnosis or treatment, (iii) or the creation of a physician--patient relationship. If you have or suspect that you have a medical problem, contact your doctor promptly.

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