The Vitamin Which May Reduce Risk of Alzheimer’s and Dementia

So a question for your doctor.
http://www.spring.org.uk/2014/08/the-vitamin-which-may-reduce-risk-of-alzheimers-and-dementia.php
Is vitamin D better than these three? Does your doctor know anything?

Leg one:
Fish Oil Supplements Reduce Incidence of Cognitive Decline, Brain Atrophy
Leg two:
Coffee May Lower Your Risk of Dementia
Leg three:
Evidence-Based Medicinal Properties of Coconut Oil - brain boosting