For millions of years humans have co-evolved with not just our external environment, but also with our internal allies – the many parasitic organisms that we host.
Modern medicine has rid us of many of those parasites but, for some of us, dumping our oldest and closest friends hasn’t worked out so well. Living parasite-free while enjoying a high-calorie diet has led to a modern-day scourge: type 2 diabetes.
Professor Robyn McDermott at James Cook University in Cairns is leading a world-first investigation of the possible benefits of parasitic worms in combatting metabolic syndrome, a collection of symptoms that often leads to diabetes.
Professor McDermott, head of JCU’s Centre for Chronic Disease Prevention, says our modern-day battles with obesity, insulin resistance and diabetes need to be understood in light of the millions of years of evolution in which we developed to thrive in dramatically different circumstances.
The focus in this investigation is the metabolic system, which chooses what fuel to burn and what to store. “Our metabolic system is brilliant,” Professor McDermott said. “It evolved to cope with scarcity and survive famine, but now it’s challenged daily by the constant availability of high-calorie food. The result can be metabolic syndrome – the cluster that often includes high blood pressure and obesity and can lead to type 2 diabetes.”
How do you know if you might have metabolic syndrome? A good start is to get out the tape measure: if your waist measurement is over 88cm (for women) or 102 cm (for men) it’s time to take action.
“Those measurements indicate central obesity, and it’s in that middle-body fat that we develop the chronic inflammation that leads to type 2 diabetes,” Professor McDermott said. “Metabolic syndrome is a serious condition. It can significantly reduce your life span and diminish your quality of life.”
It’s chronic inflammation that provides the connection between diabetes and parasitic worms. When central fat (around the waist) accumulates, it sets up a chronic inflammatory state which can lead to fatty liver, heart disease and diabetes.
“We have found in mice that a small dose of worms can powerfully reduce that inflammation,” Professor McDermott said. In humans, we’ve observed that sub-clinical worm infections – that is, infections without symptoms – reduce the risk of type 2 diabetes and metabolic syndrome.”
At the Australian Institute of Tropical Health and Medicine at JCU, immunologist Dr Paul Giacomin and colleagues have developed a safe and reliable protocol for managing hookworms in a clinical setting, and have had great success in using them to reduce inflammation in people with coeliac disease.
“Parasitic worms are masters at controlling inflammation,” Dr Giacomin said. “For millions of years they’ve been dialling back the human immune response just enough to permit their own survival, and we have co-evolved with them.”
The research team is now seeking help from women in the Cairns area to investigate whether hookworm might help to rebalance those two driving forces, our metabolic and immune systems.
“With metabolic syndrome we’re seeing an immune system that’s in overdrive because it’s not being regulated by parasites, and a metabolic system that evolved to deal with scarcity, but is now confounded by abundance,” Professor McDermott said.
“We’re investigating whether it might be possible to restore balance, reduce inflammation and stop the progression from metabolic syndrome to diabetes. In this first stage we’re aiming to establish that a low dose of hookworms is a safe and tolerable treatment.”
Like the researchers investigating coeliac disease and asthma, Professor McDermott envisages that one day a medication based on hookworm proteins might help prevent inflammation-based disease.
“We’re a long way from that stage, and that’s why we’re looking for volunteers who are interested to play host to a small dose of hookworms, each less than a quarter centimetre in length.”
Professor McDermott acknowledges that it’s not the most inviting prospect, but hopes to find enough women who are willing to support what could be an important scientific breakthrough, while learning more about their own health.
“This trial will be critical for determining whether we should start looking for the active molecules that worms release into the body to control metabolism, which could be produced as a drug for preventing type 2 diabetes,” she said.
This clinical trial has received a grant from the Far North Queensland Hospital Foundation.
For more information about the trial, please call 0439 923 422.
Q & A
Who can take part?
Women in the Cairns region who are aged between 18 and 44, with a waist measurement of 90cm or more.
How many worms will I be given?
You will be randomised to receive either a placebo, or a dose of 20 worms or 40 worms.
How big are they?
Tiny. Take a fine-tip pen and draw a line a quarter centimetre long. They’re smaller than that.
How are the worms applied?
A small patch will be applied to your skin. You’ll feel a slight tingle.
Could my family catch hookworm from me?
No. So long as you use a toilet, your hookworms will not pose a threat to others.
What happens to the worms at the end of the trial?
Trial participants will be given such a low dose, their worms are likely to die during the trial. Surviving worms are easily treated with an over-the-counter medication. In the coeliac trial many participants chose to keep their worms after the trial was finished as they felt very well.
How does it feel to have hookworm?
Some participants in previous trials (for coeliac disease) felt some bloating and slight discomfort at first. These symptoms generally eased.
Will I lose weight?
The trial is not designed for weight loss, but mouse studies show decreased weight as well as reduced inflammation and diabetes, while the mice remained healthy. We expect to see a similar effect in humans. Participants will receive a free DXA scan, which measures body fat very accurately. You will be able to see if your central fat has decreased by the second DXA scan at 12 months.
Why is the trial only open to women?
Young women seem to be gaining weight rapidly, and at a faster rate than men. Some of the tests we are using differ between men and women. We are also interested in improving young women’s metabolic health as obesity can impact badly on future babies.
(Source: James Cook University)