Switching to a low-salt diet could help tackle snoring, suggest Brazilian researchers. A clinical trial is underway to test the theory on patients with severe obstructive sleep apnoea or OSA. In this condition, which is thought to affect one in 20 adults, the throat closes repeatedly during the night, blocking air-flow into the lungs. These pauses, known as apnoeas, cause the patient to temporarily stop breathing as they sleep.

The problem is caused by the muscles and soft tissues in the throat relaxing and collapsing. The airway is blocked for ten seconds or more before the brain acts to get the muscles moving again. Symptoms include heavy snoring, and daytime tiredness because the apnoea disrupts sleep.

The condition is also associated with high blood pressure and related heart problems. It’s often first picked up after the patient’s partner notices the snoring, as well as alarming pauses in breathing. Risk factors for sleep apnoea include being overweight, drinking, smoking, being over 40, having a large neck, the menopause (because hormonal changes can lead to throat muscles relaxing), and some medicines, including sleeping pills. OSA is also three times more common in people with diabetes, and twice as likely in those who suffer chronic nasal congestion. In the trial, which started last month at the Hospital de Clinicas de Porto Alegre, Brazil, 54 patients will take a diuretic pill every day, switch to a low-salt diet, or have no treatment. The number of apnoeas the patients suffer will be compared after one week.

The diuretic pill and low-salt diet will both reduce the patient’s salt levels. It’s thought excessive salt intake leads to a build up of fluid in the body – when the patient is lying down, this fluid shifts into the neck during sleep, leading to a narrowing of the upper airways, and sleep apnoea. Diuretics work by causing the kidneys to increase the amount of salts, such as potassium, which are filtered out of the blood and into the urine. Water is drawn out alongside the salts, so diuretics also increase the amount of fluid removed from the body.

Previous research on heart failure patients at the University of Toronto found reducing dietary salt has a positive effect on sleep apnoea. The researchers said salt intake in sufferers was almost twice that of the other patients. The new trial will compare the effects of a low-salt diet with a diuretic pill. Commenting on the study, Professor Jim Horne, of the Sleep Research Centre at Loughborough University, says: ‘The idea is that these treatments will reduce the swelling around the throat and thus reduce snoring and apnoea. The diuretic will, however, cause more visits to the toilet during the night and thus create another form of sleep disturbance.

‘And for those with a fat neck, the weight of the fat further compresses the throat when lying, so sleeping propped up in bed with more pillows can be helpful, as this helps take this weight off the throat – I suspect this would be an easier, effective and quicker method. ‘Heavy snorers with OSA should see their GP to get referred to a sleep clinic.’ However, recent research has found the NHS is failing to fully address the widespread problem of sleep apnoea. A study, published in the journal Thorax, found 80 per cent of people with sleep apnoea are never treated because of a shortage of sleep clinics. The condition was found to be most common in Wales, East Anglia, East Yorkshire, Lincolnshire and the North-East – yet NHS sleep centres are concentrated in cities where the condition is less common.

source: Dailymail UK