How Hookworms May Keep Ulcerative Colitis at Bay
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Key Takeaways
A small study showed that using hookworms could be a promising new treatment for a type of inflammatory bowel disease called ulcerative colitis.
Thousands of people with inflammatory bowel disease have claimed that they’ve successfully used hookworms to reduce gut inflammation, but that evidence was just anecdotal.
Since the study was small, more research is needed to show that hookworms could be a safe, effective treatment for UC or other types of inflammatory bowel disease.
Years of anecdotal evidence suggest some patients with ulcerative colitis have successfully used hookworms to relieve the symptoms of the disease. And a recent pilot study confirms the practice is likely safe.
The study was small, featuring only 20 patients who had been in ulcerative colitis remission. But the researchers already think the promising results could pave the way for more research not just on ulcerative colitis, but other inflammatory diseases as well.
“The effect of hookworms may not be strong enough to push someone from an active disease state into disease remission,” Tom Mules, MD, lead author of the study and a gastroenterologist working at the Malaghan Institute of Medical Research, told Verywell. “However, once someone is in remission, hookworm could keep someone there, prevent them from having disease flares, and reduce the need to take medication, such as steroids, which suppresses the immune system and has adverse effects.”
Here’s what experts say about the potential of hookworms as ulcerative colitis treatment, and whether it could be an option coming to your provider’s office anytime soon.
Related: Worms That Can Make Humans Sick
What Are Hookworms?
Human hookworm (Necator americanus), is a parasite that gets into the small intestine and feeds on blood. Hookworm infections affect about 700 million people around the world.
In places with poor sanitation, hookworms are shed in the feces of infected people and find their way into the soil where they feed off environmental microbes. Hookworms can infect people through the skin—usually when they’re walking barefoot—or if they ingest the worm’s larvae.
In parts of the world where hookworm infections are not widespread, the worms are being explored as a probiotic treatment to curb gut inflammation and promote wound healing.
Related: Hookworm and Other Tropical Diseases
How Is Ulcerative Colitis Usually Treated?
Ulcerative colitis is a type of inflammatory bowel disease that causes inflammation of the large intestine (colon). The disease leads to open sores and ulcers in the intestines that can cause severe abdominal pain and diarrhea.
There is no cure for ulcerative colitis, and the symptoms are typically managed with medication, changes in diet, clinical trials, and surgery for severe cases. The goal of treatment is to reduce flare-ups, decrease inflammation, and improve the immune system.
The standard medication treatment is not always successful—about 30% of people living with ulcerative colitis end up needing to have part of their colon removed surgically (colectomy) as a last resort.
Related: What Is Ulcerative Colitis (UC)?
Why Would Hookworms Help Ulcerative Colitis Symptoms?
Researchers have been looking for new safe and effective treatments that could be combined with current options. For example, a 2021 study found that drugs used to lower cholesterol (statins) may also help reduce inflammation in people with ulcerative colitis and lower their risk of colectomy by 50%.
While it’s more unexpected, hookworms are another possibility that researchers are seriously considering.
“I can see hookworm therapy being just another tool that clinicians can use to treat disease,” said Mules. “It may not suit everyone, but it is important to provide patients with options.”
Hookworm infection causes mild symptoms like a localized rash, abdominal pain, and diarrhea, but it also may have some anti-inflammatory effects. When the worms nest themselves in the intestinal lining, that response may help reduce colitis symptoms in people with ulcerative colitis.
In the Malaghan Institute pilot study, hookworms were introduced into the body through a cream applied to a patient’s forearm. The cream contained 30 hookworm larvae that would get into the person’s body and make their way to the gut. From there, the researchers could see if the worms prompted an anti-inflammatory response.
Half the patients received hookworms for the treatment and half got a placebo. After 52 weeks, about 40% of the hookworm group was still in remission compared to 50% of the placebo group. All members of the treatment group had an increase in disease-fighting white blood cells on their blood tests, and the patients in the hookworm group did not report any serious side effects.
The researchers concluded that the patients who got the hookworm cream did have an increase in white blood cells that help the immune system and did not report any serious side effects from the treatment.
“It may not be for everyone,” said Mules. “But the fact that many people do it already suggests many are open to the idea. People hate taking medication so most people love the idea of taking a therapy which reduces the need to take pills.”
"I can see hookworm therapy being just another tool that clinicians can use to treat disease."
Tom Mules, MD
Some experts think that the hygiene hypothesis may play a role in ulcerative colitis. The hypothesis suggests that people who grew up in hygienic environments did not get exposed to microbes that would give their immune systems an important boost. The theory also suggests that people living in certain parts of the world are more protected against inflammatory bowel disease because of their unique gut bacteria.
However, not all experts agree with the hygiene hypothesis and others caution that the relationship between hookworm infections, the immune system, and inflammatory bowel disease might be more complex.
Related: UC vs. Crohn's: Similarities and Differences
“In basic studies prior to any clinical work, treatment with hookworm appears to reduce inflammatory proteins and possibly improve the gut bacteria or microbiome,” Kian Keyashian, MD, clinical director at the Inflammatory Bowel Disease Program at Stanford School of Medicine, told Verywell. “These might be some of the explanations for any benefit gained from hookworms.”
Learn More: How Common Is UC?
Does Hookworm Treatment Have Side Effects?
While the side effects reported by the participants in the study were not serious, Keyashian said that a hookworm infection can lead to some problems such as:
Dehydration
Rashes
GI symptoms (e.g., nausea, vomiting, pain, bleeding)
Nutritional deficiencies
Takeaway
If you have inflammatory bowel disease, do not try hookworm or any other treatment without talking to your provider.
Are Hookworm Treatments Coming Soon?
Keyashian said that “larger studies are needed to confirm the results of this small study, particularly as it relates to safety and long-term use of hookworms.”
Future research would look more closely at how hookworms work in the gut for people with UC and what might happen if people have the treatment more than once or over a long time.
“A much larger study is needed to prove if it is beneficial,” said Mules. “Unfortunately, this takes time and money. We believe hookworm therapy has enough promise and potential advantages over conventional medications that this should be conducted.”
What This Means For You
Many people with inflammatory bowel disease like ulcerative colitis have tried hookworm treatments to ease their symptoms, and a new study suggests that it could be a potential treatment. More studies are needed to find out if using hookworms to treat UC symptoms is safe and effective, though.
Learn More: How UC Flares Are Managed
