A woman in her 40s has been taken to hospital in Israel with brain damage after being put on a strict juice diet.

The woman, who was not identified, had been on the diet for three weeks after visiting an 'alternative therapist' in Tel Aviv.

As part of the diet she was only allowed to consume fruit juice and water, which caused an imbalance of salt in her brain.

A woman in her 40s suffered brain damage after drinking nothing but fruit juice and water for three weeks as part of an extreme diet programme (file image)

She has been under observation for three days and medics fear the damage may be permanent, Ha Hadashot 12 reported.

The diet also caused the woman's weight to plunge to less than 90lbs (40kg).

In Israel, no qualifications are required for someone to call themselves a therapist and start giving out health advice, Hadashot reports.

While the woman's exact condition was not listed, she was likely suffering from hyponatraemia, also known as water intoxication.

The condition is caused by low levels of sodium in the blood and commonly occurs in people who drink a lot of water while recovering from stomach upsets without replacing electrolytes.

However, extreme 'detox' diet have been known to cause the condition which, in extreme cases, can result in seizures and heart problems.