We now have proof.
The vitamin, B12, found in meat, fish, fortified cereals and milk, is crucial to the formation of red blood cells and the maintenance of a healthy nervous system.
Research has shown that many elderly people have low levels of the vitamin.
Rebecca Wood, chief executive of the Alzheimer\’s Research Trust, which helped fund the research, published in the journal Neurology, said: "This study suggests that consuming more vitamin B12 through eating meat, fish, fortified cereals or milk as part of a balanced diet might help protect the brain. Liver and shellfish are particularly rich sources of B12.
"Vitamin B12 deficiency is a common problem among elderly people in the UK and has been linked to declining memory and dementia."
Declining memory and dementia, eh? Explains a lot about the vegetarian movement….