Science Looking For Link Between Diet, Dementia. But Is A Link Even Possible?

A study from late 2021 attempted to link anti-inflammatory foods like fruits, vegetables, beans, and tea with lower risks of dementia. But the study, like most literature surrounding dementia, failed to provide a causal link between inflammatory foods (sugar, unhealthy fats, etc.) and the disease; meaning that anti-inflammatory foods may have simply improved general health enough to naturally stave off dementia.

For decades, doctors just assumed mental diseases like Alzheimer’s and dementia boiled down to a roll of the dice. But as modern medicine slowly begins adopting a more holistic mindset — that the body is one complete system in which all systems work in harmony…or disharmony — doctors will more readily admit that diet and lifestyle choices over the course of a lifetime may play a part in that “roll” of the dice.

“I don’t think there’s any question that diet influences dementia risk or a variety of other age-related diseases,” says Matt Kaeberlein, a research scientist who studies aging at the University of Washington. But “are there specific components of diet or specific nutritional strategies that are causal in that connection?” He doubts it will be that simple.

In the United States, around 6.5 million seniors live with dementia; and as life expectancy continues to extend, that number could balloon up to 14 million in the next 40 years. And yet, pharmaceutical companies haven’t been able to create any treatments beyond basic symptom-management medications. Perhaps the key to unlocking a quality of life for seniors begins long-before diagnosis.

“Really what we need to do is try and prevent it,” says Maria Fiatarone Singh, a geriatrician at the University of Sydney.

Dementia is as complex and patient-specific as a lifetime of eating choices

But finding causal links between vitamin-heavy or anti-inflammatory diets and dementia would require multiple decades and plenty of “luck,” considering doctors do not know who will eventually develop the brain disease.

Dementia is a disease of aging that takes decades to unfold, Kaeberlein says. To show that a particular diet could reduce the risk of dementia, “it would take two-, three-, four-decade studies, which just aren’t feasible.” Many clinical trials last less than two years.

To make matters worse for researchers, there’s the problems of intervention and duration. When should researchers begin asserting better diets into study participants? In their 50s, their 60s? Will a decade of controlled dieting prove useful information for researchers? Or will the “roll” of the dice still win the day?

“We’ve got a problem of timescale,” says Kaarin Anstey, a dementia researcher at the University of New South Wales in Sydney.

Not to mention all the complexities that come with studying diet. “You can’t isolate it in the way you can isolate some of the other factors,” Anstey says. “It’s something that you’re exposed to all the time and over decades.”

The future of dementia prevention research, therefore, likely lies in multi-intervention studies. If dementia is heterogeneous, meaning its root cause differs between different patients, then research studies should attempt to address multiple risk factors — diet being just one of many.

A trial that tests multiple interventions “allows for people to not be perfect,” dementia researcher Nathaniel Chin of the University of Wisconsin–Madison says. Maybe patients can’t follow the diet exactly, but they can stick to other portions of the study, like the workout program or brain cognition games — one of which could have an effect on its own.