According to a paper published in the Journal of Agriculture and Food Chemistry eating a high fat diet can (apparently) cause impairment in physical and mental functioning, similar to age related decline. But before you start to panic it seems american blueberries can go some way to countering this effect.
It has already been shown that consuming american blueberries can improve the memory of older people. The question the researchers wanted to address in this paper was can it reverse the deficit caused by a high fat diet.
Mice were fed a high fat diet, a low fat diet, or a high fat diet suplemented with blueberries. The results? Mice fed a high fat diet without blueberries showed signs of memory impairment. This was not observed in the low fat or the blueberry high fat fed groups.
If this species of blueberry can have this effect one has to wonder what effect european blueberries or cranberries would have….