The researchers – from Oxford's Nuffield Department of Clinical Neurosciences - conducted a clinical trial with 156 elderly patients who had mild cognitive impairment and a high risk of dementia and Alzheimer's disease. The researchers randomized the patients and for two years, gave one group a daily supplement with 800 micrograms of folic acid, 20 milligrams of vitamin B6, and 500 micrograms of vitamin B12. They gave a placebo supplement to the control group.

Before the trial and during the testing period, the researchers utilized magnetic resonance imaging (MRI) to measure the patients' atrophy levels of grey matter in their brains. Atrophying grey matter is a sign of the progression of Alzheimer's disease and other forms of dementia. Atrophy in the grey matter is shown as the amount of grey matter shrinks in the imaging tests.