I'm surprised they didn't mention the keto diet in the WSJ article.
In this paper, we highlight how an excess of dietary carbohydrates, particularly fructose, alongside a relative deficiency in dietary fats and cholesterol, may lead to the development of Alzheimer's disease
A reading of the literature on in-vivo and in-vitro studies of the effects of flavonoids (the colored components of many fruits and vegetables) on mamamalian biochemistry does suggest that they may have a significant role in maintaining health. I'd like to put it more strongly than that but it's as well to be cautious.
In this paper, we highlight how an excess of dietary carbohydrates, particularly fructose, alongside a relative deficiency in dietary fats and cholesterol, may lead to the development of Alzheimer's disease
http://www.reddit.com/r/ketoscience/comments/32ew4h/nutritio...
There's also the recent UCLA study where 9/10 patients improved after going on a keto diet http://neurosciencenews.com/alzheimers-memory-loss-reversal-...