Giardia lamblia is one of the most common causes of parasitic infections in the United States. It is responsible for 200 million infections in people worldwide each year (more common in developing nations), including 500,000 reported annual deaths.
Chronic infection with Giardia can result in significant imbalances in gastrointestinal (gut) health and can even lead to chronic health issues, making awareness of this condition vital.
This article will discuss how infection with Giardia occurs, what symptoms are associated with this parasite, how to test for it, and what conventional and natural treatment options are available.
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What is Giardia?
Giardia lamblia is a microscopic intestinal parasite, also called Giardia duodenalis or Giardia intestinalis. When humans and other mammals contract G. lamblia, most commonly through contaminated water, the infection is called giardiasis.
After Giardia cysts are ingested and exposed to the stomach's acidic environment, a trophozoite emerges from the cyst in the upper part of the small intestine, where it replicates. After the trophozoites are exposed to biliary fluid, some of them form cysts in a lower part of the small intestine and are passed into the stool, where they can then be transmitted to another host.
This parasite can survive outside the body for weeks, or even months, making hygiene practices very important in infection prevention.
What Causes Giardia?
Giardia lamblia is most commonly contracted by ingesting contaminated water, but it can also be acquired from food or even direct fecal-oral contact with an infected person or animal.
Giardia is more prevalent in countries with poor sanitation practices, so it's common for people traveling to these countries to contract it. Because Giardia is transmitted by the fecal-oral route, oral-anal sex with an infected person can cause giardiasis, and contracting it is more common in places where feces can easily spread, including daycare centers.
It's also common for campers or hikers to contract giardiasis after drinking contaminated water from a river or stream. This is why giardiasis is sometimes referred to as "beaver fever." This is in reference to a group of hikers that contracted it at Banff National Park after drinking stream water contaminated with Giardia by beavers.
Giardia Symptoms
Giardiasis can cause symptoms, typically occurring 1 to 3 weeks after infection. Symptoms can include diarrhea, nausea, abdominal cramps, fatigue, and dehydration.
Acute Giardia lamblia infections can cause watery diarrhea. However, chronic infections are classically associated with foul-smelling greasy diarrhea (called steatorrhea) that tends to float in the toilet water.
It's just as common for Giardia infections to be asymptomatic, with 50-75% of children not showing symptoms.
Chronic infection with Giardia results in significant imbalances in gut health, including dysbiosis, increased permeability of the gut lining (often referred to as ‘leaky gut’), nutrient malabsorption (Vitamin A, Vitamin B12, iron, zinc, and fructose), food sensitivities, weight loss, as well as failure to thrive or stunted growth. Chronic infections can also result in lactase deficiency leading to lactose intolerance, which often persists even after the infection is resolved. Chronic giardiasis can result in conditions like Irritable Bowel Syndrome (IBS) and Chronic Fatigue Syndrome (CFS).
An interesting characteristic of Giardia is that while most intestinal infections cause inflammation, there is little to none present with giardiasis. It does, however, elicit strong immune responses.
Testing for Giardia
Conventional medicine testing for parasites typically includes a stool ova and parasite (O&P) test, which can detect whether parasites and their eggs are present in your stool.
Functional Medicine labs testing for Giardia would include a Comprehensive Stool Analysis, which is a more specific test than the conventional O&P. Comprehensive stool tests are able to test for specific parasites, including Giardia. In addition to testing for parasites, a comprehensive stool analysis also evaluates other aspects of gastrointestinal health, such as immune function, inflammatory response, digestion, and absorption.
An excellent choice for evaluating Giardia would be the Diagnostic Solutions' GI-MAP. This comprehensive stool analysis not only specifically tests for Giardia but also quantifies how much of an organism's DNA is present in the stool sample. This could help determine if a particular treatment approach is working if retesting is performed after treatment.
If you're only looking to test for parasites and don't want the full array of data that a comprehensive stool test offers, another testing option is the Doctor's Data 3-Day Parasitology Test. This test involves collecting stool samples on three separate days to evaluate for parasites. It will provide information about whether the parasites are present. However, this test does not quantify how much of the organism's DNA is present.
An important testing consideration if a patient is not responding or resistant to treatment is that other individuals with whom the person is in close contact should also be tested. The patient may be resistant to treatment because they continue to be infected by an asymptomatic infected person in their life.
Conventional Treatment for Giardia
Conventional Treatment for Giardia includes treatment with antigiardial medications, such as metronidazole, tinidazole, and nitazoxanide. In recent years, resistance to common antigiardial medications has become more frequent, making an integrative approach to this infection a critical option.
Integrative Medicine Treatment Protocol for Giardia
An Integrative Medicine approach to Giardia is especially useful given the increasing resistance of Giardia to conventional treatments. An Integrative Medicine approach includes a combination of nutrition and nutraceuticals and, of course, a discussion of the prevention of reinfection with Giardia.
Nutrition
The best nutritional approach for Giardia is to focus on foods that support gut health and avoid those foods known to pose a problem in this condition.
Given that Giardia is associated with disruption to the balance of microbes in the intestines (called the gut microbiome), as well as malabsorption of fats, lactose, and fructose, the best way to approach nutrition during a Giardia infection is to focus on whole foods that are high in fiber and low in fat, lactose and refined sugars (especially those high in fructose).
Focus on a diet that supports gut health by avoiding foods that disrupt the microbiome, and consuming foods that are high in prebiotics and probiotics to support a healthy microbiome.
It's also crucial to focus on drinking enough water as dehydration is a common feature of not just giardiasis but of diarrhea in general. Drinking half of your body weight in fluid ounces of filtered water daily is a good rule of thumb for staying hydrated (as an example, a 150 pound person should aim to drink 75 fluid ounces of filtered water each day.)
Complementary and Alternative Medicine
Berberine Supplements
Berberine is a compound found in several plants that has been shown to be effective against several pathogens that cause diarrhea, including Giardia.
Garlic Extract Supplements
Garlic extract has potent antimicrobial properties and has been shown to be effective against Giardia.
Wheat Germ Supplements
Wheat germ contains a protein called Wheat Germ Agglutinin (WGA) shown to kill Giardia effectively. It should be noted, however, that wheat germ does contain gluten, so anyone with wheat or gluten allergy or sensitivity should avoid this option.
Bowel Support
Several supplements may be helpful support for digestive and bowel function and microbiome health during the treatment of Giardiasis. Probiotics and prebiotics in supplement form are excellent ways to support a healthy microbiome and overall gut health. Since Giardia is associated with malabsorption, extra digestive support in the form of digestive enzymes may be helpful.
Giardia Prevention
Since Giardia is most commonly contracted by ingesting contaminated water, a preventive measure must include avoiding drinking untreated water. Stick to purified water. Water filtration tools like the LifeStraw, which can filter out bacteria, viruses, and parasites, are excellent options for traveling, camping, or hiking. Boiling water for 5 minutes can also kill parasites. When traveling to foreign countries, stick to drinking bottled water.
Other preventive measures should include strict hygiene practices, including washing produce with treated water, cleaning surfaces that may have come in contact with Giardia, and washing hands often. In addition, using protection during oral-anal sex and washing hands or showering after sex can help prevent the spread of Giardia.
Summary
One of the most common causes of parasite infections in the United States, Giardia lamblia is a microscopic parasite that causes an intestinal infection called giardiasis. Giardia infections can be symptomatic or asymptomatic.
Symptoms of Giardia include watery diarrhea, nausea, stomach cramps, and bloating. However, the classic symptom associated with chronic Giardia includes foul-smelling, greasy diarrhea. Those that experience chronic Giardia often have malabsorption of several nutrients, and it can even lead to Irritable Bowel Syndrome or Chronic Fatigue Syndrome.
Given the increasing resistance of Giardia to conventional treatments, an Integrative Medicine approach to giardiasis is extremely valuable. This approach includes comprehensive stool testing to identify the parasite. Treatment consists of a combination of nutrition and nutraceuticals, as well as a discussion of how to prevent reinfection with Giardia.
If you suspect you have a Giardia lamblia infection, talk to your Functional Medicine practitioner about how to identify and treat this parasitic infection.
