In a year crowded with bad news, there was disappointment for Alzheimer’s sufferers: In November, Eli Lily announced the results of a heavily anticipated new drug designed to delay the progression to Alzheimer’s disease. Like every other Alzheimer’s prevention drug before it, this too has failed.
This has raised a whole new set of doubts about the treatment of degenerative diseases of the brain. As a neuroscientist, I can’t help but think it is unlikely we will have medicines that can decrease the risk of brain disorders like Alzheimer’s disease in the foreseeable future.
Yet all hope is not lost. An emerging body of evidence suggests that what can’t be solved by pills might well be solved by food. But like everything in the complex world of nutrition and brain health, the story is anything but simple or complete.
The answer isn’t cutting out sugar, or going on a detox — it’s adopting a healthy diet in general. Diets rich in green vegetables, nuts, whole grains, fish and olive oil that include a glass of wine or a cup of coffee here and there — and by that I mean one or two per day — are associated with better brain health. It has long been known that this kind of “Mediterranean diet” is good for the heart, but emerging research shows that it appears to also be good for the brain, too.
The brain, however, appears different from the heart in one interesting respect — eating berries a couple of times a week with a Mediterranean diet appears to benefit the brain. That said, with the possible exception of fish, there doesn’t appear to be one single food or magical nutrient that can make a difference to brain health on its own.
So what is bad?
Supplements. Shelves and shelves of pills and apparently magical extracts promise to improve your memory. They don’t work.
Also, eating too much — of anything — continues to be a problem. Just as it is with heart disease, obesity is a risk factor for brain diseases. Similarly, diets high in fried and fast food, sweets and some fats, especially those high in what are called omega-6 fatty acids, and, possibly, soft drinks, are also associated with poor brain health. Most of these foods only show benefit or harm when eaten as a pattern.
In other words, the odd cheeseburger won’t cause memory loss. But the odd handful of almonds won’t prevent it, either. It isn’t about how you eat once a week, but how you eat every day.
All of this, it should be said, is qualified by a big caveat. The field of nutrition and brain health is relatively new. Most of the data we have is generated from what are called “observational studies.” When we look at the population, we see that people who eat diets rich in green vegetables, nuts, whole grains and so on seem to have a lower likelihood of developing Alzheimer’s disease. This shows an association. But it doesn’t prove that the healthier diet is actually preventing Alzheimer’s. For that you need what’s called a randomized clinical study.
On a positive note, some clinical studies are starting to offer corroborating evidence for what we see in the observational studies. For example, over the past few years a large study looked at people eating a Mediterranean diet. The study was designed to measure heart disease. However, when the authors took a second look at the data, which is by no means ideal, they noticed that the subjects on the Mediterranean diet also had better cognitive function.
What we need now are more of the big nutrition clinical trials similar to the kind we use to test the effectiveness of new Alzheimer’s drugs. Until we run studies of this nature, directly testing if nutritional interventions work, we won’t truly know if we can eat our way to better brain health.
A toast, then, to a diet rich in green vegetables, nuts, whole grains, berries, fish and olive oil. It’s good for your heart, and it’s probably good for your brain. I can’t think of a better New Year’s resolution.
Richard Bazinet is a professor of nutritional science and the Canada Research Chair in Brain Lipid Metabolism at the University of Toronto’s Faculty of Medicine. Doctors’ Notes is a weekly column by members of the U of T Faculty of Medicine. Email [email protected]