Our brains don't like being overfed, as obesity can age the brain prematurely and even make it more vulnerable to Alzheimer's and Parkinson's. Now we've discovered the opposite effect: a strict diet turns on molecules that keep the brain young.
Scientists searching for the key to extending human lives have put a lot of attention on caloric restriction, which means placing someone on a near-starvation diet that only allows 70% of normal food consumption. In animals, caloric restriction has repeatedly been shown to greatly extend normal lifespan. We don't know for sure whether this would work in humans, but that's partially because it could take a hundred years to test it out on humans.
But the advantages of caloric restriction don't just deal with longevity, according to researchers at the Catholic University of Rome. Mice placed on these extreme diets show greater cognitive abilities than their counterparts and they are less aggressive. Most excitingly, they only rarely develop Alzheimer's disease, and when they do the symptoms tend to be much less severe than in those of other mice. Effectively, caloric restriction is keeping mouse brains young.
That's all well and good, but it isn't of much use to us humans if we don't know why such diets make the brain younger - after all, we can't just starve a bunch of people for the next thirty years and hope their minds improve. Ethically speaking, that's a no-no. That's where the Italian researchers have made such a crucial breakthrough. They've identified the specific molecule that is activated by caloric restriction, and how it changes the brain.
That molecule is called CREB1, and it's triggered by these extreme diets. In turn, the molecule activates genes linked both to longevity and to the proper, more efficient functioning of the brain. We already knew that CREB1 helps regulate brain functions like memory, learning, and control of anxiety, and that aging reduces the effect of this molecule. Now we know that reduced caloric intake can improve the molecule's performance, and even slow the onset of aging in the brain.
In fact, it seems that the benefits of caloric restriction in the brain are all to do with CREB1 - when the molecule is removed from the mouse's brains, caloric restriction has no cognitive benefit. The researchers believe this same mechanism should exist in humans. Team leader Dr. Giovambattista Pani says he hopes to discover new drugs that can super-charge the activation of CREB1 without having to endure such an extreme diet. If they are successful, we could keep our brains younger and fitter than ever, while still being allowed to enjoy a good meal.