Our Western diet of sugars, salt, refined carbs and bad fats has been linked to higher risks of heart disease and diabetes, liver disease, strokes and multiple types of cancer. It is the lead cause of an obesity epidemic that is killing an estimated 300,000 Americans a year as well as costing the health system $173 billion.
Now a team of scientists argue it may be behind the Alzheimer’s disease epidemic as well.
Sugars and other “high glycemic” carbs (meaning carbs that cause a quick spike in blood sugar), salty foods, alcohol, processed red meats, organ meats, shellfish and beer are among the foods named in a new paper published in the American Journal of Clinical Nutrition and co-written by researchers from the Rocky Mountain VA Medical Center in Colorado, the University of Colorado, Boston University, the University of California Los Angeles, the University of Miami, and the National Institute of Cardiology in Mexico.
The paper links Alzheimer’s with excessive fructose, the sugar typically associated with fruits, but the paper’s main focus isn’t on fruit. These have “a relatively low fructose content” compared with processed foods, and also neutralizing factors in fruit such as fiber and vitamin C.
Instead the real culprits are foods with “added sugars that contain fructose and glucose” such as table sugar and high-fructose corn syrup, along with foods that stimulate the body to produce its own fructose: That means “high glycemic carbohydrates, alcohol, and salty foods.”
The reason? When we consume a lot of fructose or these foods, it tricks our bodies into thinking we are about to enter a famine. And not just an intermittent fast, but the kind of “seasonal starvation that occurred in the middle Miocene subepoch,” when humans were threatened with extinction, they argue.
These foods flip a “survival switch,” causing a complex set of reactions by different parts of the body designed to make the human prepare for the famine above anything else: “an orchestrated response to encourage food and water intake, reduce resting metabolism, stimulate fat and glycogen accumulation, and induce insulin resistances as a means to reduce metabolism and preserve glucose supply for the brain.”
The body also redirects energy to the parts of the brain specifically needed to survive a pending famine, such as those good for foraging. Other parts of the brain get less energy than they need as a result.
“AD [Alzheimer’s disease] results from a maladaptation to an evolutionary survival pathway that is used by many animals and was even essential to the survival of our distant ancestors millions of years ago,” they argue.
The latest paper isn’t the first to suggest a link between our toxic “Western” diet and Alzheimer’s. These include this, this and this.
Lab rats in the past given lots of fructose have developed tau proteins and amyloid plaques in the brain, markers of dementia.
Researchers also recently argued that switching from a Western diet to a healthier one could add a decade to the life expectancy of a young person in the U.S.
It’s pretty intuitive that the Western diet would be bad for us. We’ve been evolving out of creatures that apparently first began to appear up to 16 million years ago, when triple-decker cheeseburgers and giant sugared coffees with whipped cream and sprinkles were hard to come by. Maybe we just have system overload.
Our brains certainly can’t cope with social media either. But that’s another story.
The good news is that we’re really adaptive. If you’re used to eating candy, an apple isn’t going to taste of much. But after a few weeks without candy—and salts, and so on—that apple will taste a lot better. I did a water fast for a week last year. At the end a slice of cucumber produced a taste explosion in my mouth.
Meanwhile Alzheimer’s continues to run rampant, currently killing about 6 million Americans, with no cure in sight. I’m happy swearing off the junk food.