When Archie Bunker called his son a "meathead" he was actually more complementary than he intended. Oxford University in England scientists have found that a meat-free diet may actually be bad for your brain. The researchers found that people who adopt a vegan or vegetarian diet are six times more likely to sustain brain shrinkage than meat eaters. The key element is that vegan and vegetarian diets fall short on Vitamin B-12, which is found in meat, fish and dairy products including cheese.

"This study suggests that simply adjusting our diets to consume more Vitamin B-12 through eating meat, fish, fortified cereals or milk may...prevent brain shrinkage and so perhaps save our memory," said Anna Vogiatzoglou, a member of Oxford's department of physiology, anatomy and genetics, in a prepared statement. "Research shows that Vitamin B-12 deficiency is a public-health problem, especially among the elderly, so more Vitamin B-12 intake could help reverse this problem."

Oxford researchers linked diet and brain size by doing memory tests, physical exams and brain scans on 107 people aged 61 to 87. The volunteers were retested five years following the first exam, and researchers discovered that those with the lowest levels of Vitamin B-12 were more likely to have suffered brain shrinkage. In earlier research, scientists established a link between brain atrophy and low levels of Vitamin B-12.

To read a summary of the study, click here