_{28 Aug 2012}

Alzheimer's triggered by "type three diabetes"

An unhealthy diet could lead to Alzheimer's disease by triggering a form of insulin resistance dubbed "type three diabetes", scientists claim.

High levels of the hormone insulin, brought on by a bad diet, may harm the brain in the same way that the muscle, liver and fat cells are affected by type two diabetes.

Exposing the brain to too much insulin could cause it to stop responding to the hormone, hampering our ability to think and create new memories and ultimately leading to permanent damage, researchers said.

A diet high in fat and sugar has long been linked to a higher risk of Alzheimer's, while studies of health among large populations have shown that a healthy Mediterranean diet may offer some protection.

In type two diabetes, eating too much fatty and sugary food raises our insulin levels to such a consistently high degree that our muscles, fat and liver cells are no longer affected by the hormone.

This means that the amount of glucose and fat in our blood is allowed to increase unchecked, forcing the pancreas to produce even more insulin to try to cope. Ultimately it becomes exhausted and production drops to very low levels.

A small-scale trial on human patients at Washington University found that those who were given a nasal spray containing insulin were better at remembering details of stories, had longer attention spans and were more independent.

For more on this see The Telegraph newspaper online.