If you often wake at night with an urge to go to the loo, you may need to cut back on salt in your diet. Frequently needing the toilet in the middle of the night – a problem called nocturia – affects more than half of over-50s.
Although it may seem a trivial problem, doctors warn that the resulting lack of sleep can lead to stress, irritability and fatigue.
But a simple dietary change can markedly reduce the problem, researchers have found.
A Japanese team of scientists, whose work was presented at the European Society of Urology conference in London, tracked 321 volunteers for three months.
They found that reduced salt intake led people to urinate less.
When 223 volunteers were asked to cut their salt by 25 percent, from 10.7g to 8g a day, their average night time toilet visits fell from an average of 2.3 trips to 1.4 times.
In contrast, when 98 subjects increased their intake from 9.9 to 11g they found that their need to urinate increased from 2.3 times a night to 2.7 times a night.
The NHS recommends that adults only eat 6g of salt each day.
The researchers also found that daytime urination was reduced when salt in the diet was reduced.
But the fall in nocturnal bathroom visits resulted in a particular improvement in people’s quality of life, they found.
Study author Dr Matsuo Tomohiro, of Nagasaki University, said, “This is the first study to measure how salt intake affects the frequency of going to the bathroom. Night time urination is a real problem for many people, especially as they get older. This work holds out the possibility that a simply dietary modification might significantly improve the quality of life for many people.”
The sodium in salt plays a key role in maintaining the correct balance of fluids in tissues and the blood.
But if too much salt is consumed, it leads to an increase in the amount of urine the kidneys produce, resulting in a condition known as polyuria – or excessive urination. In severe cases this can cause oedema, or swelling, where the fluid is retained under the skin, often in the feet or ankles.
High salt intake makes people drink more, because they tend to be thirstier, further compounding the problem.
Professor Marcus Drake, a urologist at Bristol University, said, “This is an important aspect of how patients potentially can help themselves to reduce the impact of frequent urination. Research generally focuses on reducing the amount of water a patient drinks, and the salt intake is generally not considered. Here we have a useful study showing how we need to consider all influences to get the best chance of improving the symptom.”
A second study presented at the same conference found that treating the condition sleep apnoea, which is often associated with loud snoring, can also prevent the need to urinate during the night.
A Dutch team found 65 percent of patients reported a reduction in night-time visits to the bathroom if they were treated with a breathing mask.
Professor Drake said, “It may seem surprising that breathing problems can cause excessive urine production while asleep, but actually the problem is very real. To have a study showing the link, and the potential benefits of therapy, may help establish the treatment into routine clinical practice.”