New research may improve the treatment of children and teenagers with acute flare-ups of debilitating and incurable Crohn's disease.
The inflammatory bowel disease is on the rise and affects 15,000 New Zealanders, including many children and young people. It is a life-long auto-immune disease characterised by inflammation of the digestive system.
The condition is often diagnosed in teens, and steroids are a common first treatment to reduce flare-ups, but they are not ideal.
Otago University Christchurch-based paediatrician Andrew Day said it was now clear a liquid-only diet works just as well.
"We've shown that this diet changes the pattern of the bacteria in the gut. We've shown that it makes the gut barrier stronger in terms of tighter connections between cells, and that it actually switches off inflammatory processes.
"Which of these mechanisms is the most important or whether they all work together isn't that clear, but more recently we're also trying to understand which components of the formula might contribute to these anti-inflammatory effects."
Exclusively liquid diet for two months
Patients are given an exclusively liquid diet - nutritionally balanced Fortisip or Ensure - for two months, before slowly re-introducing solid foods.
Professor Day said almost all patients went into remission, and while not a cure, it enabled the gut to heal.
He said the diet, known in gastroenterology circles as Exclusive Enterel Nutrition (EEN) is recommended under current New Zealand guidelines, but said the evidence of its effectiveness had been sparse.
He said data over the past decade showed that it was the treatment used for both adults and children in Japan.
"We have a PhD student that's currently working with us at the moment looking in adults from 16 to 40 and showing that this treatment can be very effective in this age group, particularly at the time of first diagnosis."
Alternative to steroids
Professor Day said the liquid diet offered an alternative to treating flare-ups with steroids, which could cause depression, acne and bloating.
An Associate Professor of gastroenterology at Otago University in Dunedin, Michael Schultz, said that was important.
"The reason for avoiding steroids is the number of side effects steroids cause specially in children with growth retardation and things like that. He [Professor Day] was able to show that Exclusive Entereal Nutrition is about as good as steroids so you can avoid steroids in this particular patient group."
Professor Day said inflammatory bowel disease was of particular interest in the South Island where Crohn's affects about 150 children.
"Canterbury has one of the highest rates of IBD, particularly Crohn's Disease, in the world. We've got data from 2014 compared to 2004 showing a substantial increase across the age range in the Canterbury region. One and a half times as many people being diagnosed in 2014 as there were in 2004."
Liquid diet leads to weight gain for Crohn's sufferer
Kaylene McArthur, from near Ashburton, said the liquid diet helped her son Logan, diagnosed with Crohn's on his 15th birthday, on 9 October 2014.
"He was suffering with anaemia very badly. He was very lethargic, had very little energy and he was incredibly underweight. Just physically drained."
Kaylene said Logan fitted the liquid diet into his normal activities, including school.
"Ashburton College were amazing. I went in and saw the staff there and they had a wee fridge in the staff room and they said that he could have the use of that fridge. And I would go in once a week and I would put a week's worth of drinks in the fridge for Logan and he would just come in when he needed to and help himself."
Logan said the diet lifted his weight from 42 kilograms to just over 50, and he was no longer as tired.
He did two rounds of the eight-week diet. The first time, he said he was "kind of sneaking around so nobody would see at school. The second time round it wasn't so bad. I got used to it."
Asked what was the best thing about having been on the diet, he said it was gaining weight.
Dr Schultz said further research was needed to determine if a liquid diet would help older people with Crohn's as well.