Researchers have found that patients with higher than normal levels of “bad” cholesterol in their blood tended to have more harmful tangles of protein inside their brain cells.

These tangles, known as beta amyloid plaques, are one of the main physical signs of Alzheimer’s disease and are thought to interfere with the way brain cells work.

The findings add to the growing evidence that suggests poor diet and cholesterol may play a role in the development of Alzheimer’s disease.

The exact causes are still to be understood, but the latest study showed that high levels of low density lipoprotein, or bad cholesterol – which is typically found in red meat – led to more tangles in the brain.

Higher levels of “good” cholesterol – high density lipoprotein which can be obtained from foods such as nuts and olive oil – were found to have a potential protective effect that lowered beta amyloid plaques.