The balloon that you swallow to lose weight
20:12 GMT, 17 September 2012
A balloon that’s inserted into a tiny capsule that you then swallow could be a radical new treatment for obesity. It works by filling up the stomach — the researchers say this makes the brain think the tummy is full, curbing appetite.
The silicone balloon is packed inside a gelatine capsule that dissolves within minutes of reaching the stomach. It’s then inflated by the doctor using a long thin tube, about the width of a piece of string, which is attached to the balloon at one end and protrudes from the patient’s mouth at the other.
Air is pumped through the tube into the balloon until it reaches the size of a hamburger. The tube is then pulled to release it and a self-sealing valve traps the air inside the balloon so that it does not deflate.
The new treatment for obesity has already been approved for use in the UK and could become available within the next year
It takes just five minutes to inflate and the patient does not need to be sedated or have an anaesthetic.
The new treatment has already been approved for use in the UK and could become available within the next year or so. Although gastric balloons are already used in the treatment of obesity, they are not without problems. These work on the same principle as the capsule but are inserted surgically.
Under existing techniques, patients often need a general anaesthetic to have them implanted, although some have it done while still conscious but under sedation.
It also requires a special type of probe — called an endoscope — to push the balloon down through the gullet and into the stomach before it can be inflated.
This can leave the patient with nausea, vomiting, abdominal pain, heartburn and diarrhoea in the first few days after the procedure because of the irritation caused to the throat, gullet and stomach.
Up to 50 per cent of gastric balloon patients experience some or all of these side-effects. Another advantage of the capsule balloon is that additional balloons can be used at a later stage if one does not have the desired effect on its own.
This cannot be carried out with conventional gastric balloons, as this would mean patients going through repeat procedures.
So far, four small trials have been carried out on humans using the balloon capsule, developed by San Diego-based firm Obalon Therapeutics.
Patients who failed to shed weight through dieting swallowed the capsule, had the balloon inflated and were then monitored for weight loss over a period of 12 weeks.
Depending on their size and weight-loss target, the patients took between one and three capsules over the 12 weeks.
Doctors measured average excess weight loss — the amount of extra weight that volunteers managed to shed.
In one group of 28 patients, average excess weight loss was 35.5 per cent over the three months, compared with an average of only about 20 cent with the conventional balloons. In two other small studies, carried out in Belgium and France, average excess weight loss was even greater, at about 50 per cent.
At the end of the treatment, a thin probe — less bulky than those used for existing balloons — is fed down to the stomach to deflate the balloon and retrieve it in a procedure that takes around ten minutes. The balloon has only been kept in the stomach for 12 weeks so far, but the scientists say it could remain in place for longer.
Commenting on the technology, Paul Trayhurn, professor of nutritional biology at Liverpool University, says: ‘It sounds promising. Gastric balloons and gastric bypass operations are being used to reduce the effective size of the stomach so that you feel full more quickly, with the result that you eat less.
‘This can have rapid benefits in terms of insulin resistance.
‘But this particular device seems a neat approach, given that no intervention is required by a clinician to get it in place — only inflation of the balloon once the capsule has dissolved.’
But he stressed that further tests are needed to assess whether the balloons are robust enough to withstand the harsh acidic environment of the stomach for long periods.
■ Meanwhile, scientists are investigating whether a prune-based gel may aid weight loss.
In a study, from the Dynamic Nutrition Laboratory in Germany, 60 moderately overweight women will take 40 g of the supplement, in pill form, or a placebo every day for four months.
The theory is that the supplement swells in the stomach and increases feelings of fullness, which will lead to a drop in the amount of food eaten each day (the patients will be allowed to eat what they like during the trial).
The team say that the pills contain the concentrated fibre found in prunes, and are more practical than eating the fruit every day, as some people dislike the taste or experience unpleasant side-effects.