Ryan Knox is taking part in the space food trial
Doctors are examining if food given to astronauts can provide long-term help to children with Crohn's disease.
The food is easier to digest because it contains treated amino acids, which can normally be difficult for the body to process.
It has been found to have short-term benefits for patients with the digestive system disorder, but experts want to look at whether they continue.
They will compare the space food - known technically as elemental feed - with the standard steroid treatment.
Steroids can thin the bones of patients, but space food apparently has no side effects.
The study, which is being carried out in four UK centres, hopes to recruit over 100 under-16s with Crohn's to take part over the next two years.
However, for some patients, like 12 year-old Ryan Knox, from Gloucester, drinking the required two litres of the food a day can prove too difficult to maintain.
He does, however, like the flavours, with chocolate being his favourite.
Hard to spot
Professor Bhupinder Sandhu, based at the Bristol Children's Hospital, is involved in the latest trial.
Already over half of her patients are given the space food, and they usually see their symptoms go into remission after a four-to-six week course. But she admits the long-term benefits remain at present unclear.
She said: "There is clinical evidence to suggest that elemental feed is as effective as steroids in healing the gut, however there is no long-term evidence yet on its lasting effect on bone density and growth."
Doctors will carry out bone scans as part of the study as well as seeing if space food is as good as, or better than, steroids.
Professor Sandhu has also been involved in drawing up new guidelines for treating the hundreds of children affected by inflammatory bowel disease (IBD).
Ross Andrew has severe Crohn's disease
IBD comprises Crohn's disease and ulcerative colitis, both of which cause chronic inflammation of the intestine.
The cause is not known, and while it can occur at any age it is rare in infancy, making it hard to spot.
Only about one in five children with Crohn's present themselves to doctors with the classic symptoms of abdominal pain, diarrhoea and weight loss.
So the new guidelines, which took two years to draw up, and are based on over 2,000 research papers, are being targeted towards paediatricians, in order to make them aware of unusual manifestations of the disease.
The disease is especially traumatic for children, who represent around 30% of cases.
Ross Andrew suffers from Crohn's disease which is so severe that he cannot eat anything and has to be fed through a tube overnight so that he can live and grow.
The 13-year-old looks three years younger, because like many sufferers, growth can be affected.
That is why it is so crucial that it is diagnosed early.
Hard to bear
His mother Susan is a trained nurse, which is just as well given all of his medical needs.
She said: "The feeding into the vein itself has caused a lot of problems.
"It has a lot of side effects and he developed jaundice quite badly, which affected his liver. He also developed gallstones."
His condition led to ulcers in the bowel and his gut is riddled with holes.
Ross said that at times, the condition can be hard to bear.
"I just want to get rid of it, so it is quite upsetting sometimes.
"Some days I can't really live with it any more."