This result was unexpected, according to lead researcher Dr. Nawab Qizilbash, from OXON Epidemiology Ltd. in Madrid, Spain. However, the study also showed a predictable increase in premature death risk from being overweight or obese. The findings need further study. For the instant, there are some ideas that vitamin D and E deficiencies contribute to dementia and they may be less common in those eating more. You can’t walk away and think it’s OK to be overweight or obese. Even if there is a protective effect, you may not live long enough to get the benefits,” said Dr Qizilbash. This study was carried out by researchers from the London School of Hygiene and Tropical Medicine, London, and OXON Epidemiology; a London/Madrid-based clinical research company.