A Diet Might Cut the Risk of Developing Alzheimer’s

http://www.wsj.com/articles/a-diet-might-cut-the-risk-of-developing-alzheimers-1429569168?mod=trending_now_1&ncid=newsltushpmg00000003
One odd thing, though:

"The study compared the so-called MIND diet with the popular, heart-healthy Mediterranean diet and the DASH diet, which is intended to help control high blood pressure. The MIND diet borrows significantly from the other two, and all are largely plant-based and low in high-fat foods. But the MIND diet places particular emphasis on eating “brain-healthy” foods such as green leafy vegetables and berries, among other recommendations.

The study, conducted by researchers at Rush University Medical Center in Chicago, found strict adherence to any of the three diets lessened the chances of getting Alzheimer’s. But only the MIND diet seemed to help counter the disease even when people followed only some of the diet’s recommendations."

If the MIND diet is largely based on the other two diets, and only following some of the MIND diet's recommendations is still effective...doesn't it follow that the other diets would show the same effect?