Intestinal Parasites: Everything You Need To Know (Including How To Tell If You Have One)

Functional Medicine Practitioner By William Cole, D.C., IFMCP
Functional Medicine Practitioner
Dr. Will Cole, D.C., IFMCP, is a leading functional medicine expert who specializes in clinically investigating underlying factors of chronic disease and customizing a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. Cole is also the bestselling author of Ketotarian and The Inflammation Spectrum.
Intestinal Parasites: Everything You Need To Know (Including How To Tell If You Have One)

The possibility of having an intestinal parasite can be scary—the idea of having an almost alien-like creature inhabiting your body is enough to give anyone the shivers. These living organisms reside in your body as its host and feed off of it to survive, which can cause a whole slew of symptoms far beyond gut dysfunction alone.

As a functional medicine practitioner, I often see parasitic infections as an underlying contributing factor to many of my patients' chronic health problems and a big reason why previous attempts at healing have been unsuccessful.

Symptoms of intestinal parasites.

Some of the most common symptoms and signs of intestinal parasites include:

  • Digestive problems including unexplained constipation, diarrhea, or persistent gas
  • Skin problems including unexplained rashes, eczema, or hives
  • Muscle and joint pain
  • Fatigue
  • Lack of satiation after meals
  • Constant hunger
  • Teeth grinding during sleep
  • Anxiety
  • Itchy skin
  • Yeast infections
  • Loss of appetite
  • Iron deficiency
  • Itching of the anus or vagina

Parasitic infections can be caused through either helminths—parasitic worms—or protozoan parasites. Single-cell protozoan parasites, like giardia, can multiply in your body and contribute to many cases of extreme diarrhea and when left untreated, dehydration, and even death.

Helminths live inside our gut and typically do not result in death but instead contribute to a lifelong struggle with chronic health problems due to their depleting nature on the body. The most common helminths are tapeworms, roundworms, flatworms, hookworms, and whipworms.

Pinworms, whipworms, and hookworms are all types of roundworms that can cause digestive problems, mood swings, abdominal pain, brain fog, and weight loss. Hookworms, in particular, can work their way outside the gut lining to feed on your blood, leading to anemia.

Tapeworms are types of flatworms that live inside your intestine and can grow up to 35 feet long, laying close to one million eggs per day. They eat the food you eat and can cause feelings of constant hunger and are commonly contracted through eating undercooked contaminated meat.


How do you get a parasite?

The shocking reality is that most everyone has some sort of parasite. Yes, even healthy individuals. It is estimated that close to 37 percent of the whole world has some sort of helminth parasite, in particular. It is a myth that you have to travel to faraway destinations in order to come in contact with these organisms. They are in our food, water, and things we come across on a regular basis.

One of the most common ways of contracting a parasite is through contaminated food, like undercooked meat and water. You can also get parasites through contact with contaminated feces—meaning: Washing hands is extremely important for those with infections. This stops the spread of the microscopic eggs through touch. Children and adults with weakened immune systems are most at risk for contracting parasites.

The reason many people even show symptoms of parasitic infection in the first place is because their health was already in a state of disarray. Like I said, the majority of people most likely have some type of parasite. The question is whether or not these parasites are fueling disease or fueling health. It's when we experience an overload or infection of parasites that these organisms cause a problem.

Intestinal Parasites: Everything You Need To Know (Including How To Tell If You Have One)


Since parasites feed off of what you eat and thrive off of junk—sugar, in particular—the unhealthier you eat, the more enticing of an environment you are providing. By damaging your microbiome and immune system, you are basically throwing open the door for these invaders to establish themselves in your body.

Once these parasites take up residence in your body, they slowly eat away at it, causing nutrient deficiencies; a suppressed immune system, which can further perpetuate disease; and severe gut dysfunction. Parasites are a double-edged sword—poor health weakens the immune system thus attracting parasites, and an overgrowth of parasites weakens your health even more.


Are parasites beneficial for autoimmune diseases?

Parasites are often demonized due to the devastating effect they can have on your overall health, but we often ignore the fact that some parasites can be beneficial. In terms of the good they can do, parasites work to turn off Th1 and Th17 inflammatory cells to quell chronic inflammation and actually increase immune-balancing (regulatory T-) cells. There is so much evidence surrounding this that helminthic therapy is on the rise for many people struggling with autoimmune and other inflammatory conditions.

While this seems like the last thing you'd want to do, deliberatively giving yourself parasites has been shown in studies to greatly reduce symptoms in autoimmune conditions, such as multiple sclerosis (MS), asthma, inflammatory bowel conditions (Crohn’s and ulcerative colitis), and type 1 diabetes.

Scientists theorize that this significant reduction of exposure to parasites in industrialized nations is a major reason autoimmune conditions are continuing to skyrocket and are virtually nonexistent in developing nations where parasites are more common. This is known as the hygiene hypothesis.

According to this hypothesis, due to our reduced exposure to microorganisms because of more sanitary conditions, our immune reactivity is increased as well as our likelihood for autoimmune diseases in response to toxins, poor diet, and other environmental factors. For years, we have co-evolved with helminths. Since their goal is to stay alive in our bodies as long as possible, helminths have been able to create a state of tolerance by modulating our body's immune system to avoid being eliminated yet also avoid suppressing the immune system enough to where it is detrimental for us. This immune-system modulation has, for centuries, helped protect us against these autoimmune-inflammatory conditions and continue to do so for those in developing nations.

Surprisingly enough, helminths can even modulate the microbiome by increasing good bacteria in the gut. And since around 75 percent of your immune system is located in your microbiome, helminths can be a powerful tool we are missing out on when it comes to our optimal health. We may all want to get back to our roots and make friends with these friendly parasites once more.

Unfortunately, helminthic therapy is not currently available in the United States but is being offered in Mexico. If you are interested in trying this therapy, it is important to work with a reputable doctor and never buy helminths over the internet, as there are many possible side effects.

Tests to get if you suspect a parasite.

If you suspect your symptoms are due to a parasitic infection, there are a few ways to know for sure if that is a factor in your health case. Once you know, you can start targeting treatment accordingly:

  1. Comprehensive stool test. This test looks for the ova, or eggs, of a parasite in your stool to determine the presence of an infection.
  2. Endoscopy and colonoscopy. This procedure can be done when a stool test fails to find any parasites. A doctor will examine your intestines with a camera through a tube inserted through either your mouth (endoscopy) or rectum (colonoscopy) to locate the parasite that may be causing your symptoms.
  3. Blood tests. Blood tests look for specific types of parasitic infections. A serology test looks for antibodies produced when the body is infected with a parasite, and a blood smear looks for parasites in the blood by examining the sample under a microscope.

How to get rid of intestinal (and single-celled) parasites.

Antiparasitic drugs, such as praziquantel and mebendazole, are the first line of defense against parasites in conventional medicine. These can cause many uncomfortable side effects almost as bad as the parasitic infection itself, including nausea, vomiting, headaches, weight loss, and insomnia. The damage parasites have caused before treatment will determine if you need additional pharmaceutical intervention.

While these medications can have their place, there are many natural herbs that possess powerful anti-parasitic properties including:

These are great options if you want to take a completely natural approach or want to take something alongside anti-parasitic medications in accordance with your doctor’s recommendations.

We also can't discredit living a clean, healthy lifestyle. This will boost your immune system to help rid your body of the parasites and reduce your risk of re-infection. It is also key to continue to support a healthy gut environment by fostering good bacteria through either a probiotic supplement and probiotic-rich foods like kefir, sauerkraut, and kimchi.

Something to be aware of if you are intensively treating a parasitic infection is the possibility of a Jarisch-Herxheimer reaction. When you attempt to kill off and rid yourself of parasites, they release an increased amount of toxins as they die off. Without proper liver support during this time, your body responds to this elevated toxin load with uncomfortable detox symptoms, like headaches or the exacerbation of current symptoms. Basically, it can get worse before it gets better. It is important to remember to start with a low dosage and gradually work your way up to avoid this reaction as much as possible (but again, talk to your doctor to figure out what's best for you).

At the end of the day, we can't look at parasites as a black-and-white issue. For being so tiny, these organisms hold immense power over our entire health. By living a healthy lifestyle, we can keep these parasitic infections at bay. But we may not want to say goodbye to our old friends completely just yet.

Suspect you might have a parasite? Here's one woman's story on what she learned after getting sick.

William Cole, D.C., IFMCP
William Cole, D.C., IFMCP
Will Cole, D.C., IFMCP, is a leading functional-medicine expert and a Doctor of Chiropractic. He...
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William Cole, D.C., IFMCP
William Cole, D.C., IFMCP
Will Cole, D.C., IFMCP, is a leading functional-medicine expert and a...
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