Low-energy diet can improve sleep disorder

Sleep apnea is a common disorder caused by abnormal pauses in breathing during sleep. Sufferers rarely feel refreshed after a night's sleep and the disease is linked to negative health effects such as increased risk of accidents, decreased quality of life and a higher chance of premature death.

Around 60-70% of patients with sleep apnea are either overweight or obese. Previous studies in other patient groups have concluded that losing weight can improve the condition.

The authors, led by Kari Johansson from the Karolinska Institute in Stockholm, investigated whether a low energy diet followed by counselling to keep weight under control benefited patients with sleep apnoea.

The study follows a previous trial by the same authors, published in the BMJ in 2009, that investigated the effects of very low energy diet for nine weeks. The new study looks at the longer term effects of weight maintenance over one year.

The study included 63 men between 30 to 65 years of age who suffered from moderate to severe obstructive sleep apnea. The participants had a body mass index (BMI) range of 30-40.

Of the 63 patients, 58 completed a very low energy diet for nine weeks and then started a one year weight maintenance programme (this included counselling and advice about nutrition and exercise).

The very low energy diet was based on the Cambridge weight plan -- this consists of a range of different flavoured meal replacement products (shakes, soups, bars and porridge) which have the necessary vitamins and minerals so that individuals can lose weight in a healthy way.

The results show that patients who lost weight after nine weeks on the low energy diet maintained this after a year and this had a positive effect on their sleep apnea. For instance, at one year, 48% of patients no longer required continuous positive airway pressure (a mask designed to help breathing during sleep) and 10% had total remission of obstructive sleep apnea.

Patients who had severe forms of the disease at the beginning of the study had larger improvement than those with moderate disease, says the study. The authors also found that patients who lost the most weight improved the most.