Myth-busting: The Truth Behind 4 Common Theories About What Causes Dementia

By | October 12th, 2023

Dementia is a complex condition with no singular cause. It doesn’t stem from one single lifestyle decision, and it isn’t an inevitable symptom of aging. But, there’s plenty of misinformation online claiming otherwise. Here are four common myths about what's behind Alzheimer's and other forms of dementia.

Alzheimer’s is a condition affecting more than 30 million people worldwide. It causes problems with language, memory, and cognition. While scientists aren’t 100 percent sure what causes every case, they have ruled some things out. Still, many myths and misconceptions about the causes of dementia persist online. Here are four simple, but inaccurate, explanations for the dementia’s cause that tend to pop up on the Internet. And they’re not just misleading, they can be hurtful too, increasing anxiety (which, ultimately, can be harmful to brain health) and stigmatizing people with Alzheimer’s disease and other forms of dementia

Myth #1: “Aluminum causes dementia.”

Science says: False.

In the 1960s and 1970s, researchers studied the link between aluminum and Alzheimer’s in animal models. Hearing about this research, some people became worried about drinking from soda cans, using aluminum cookware, or even antiperspirants. The myth is still making the rounds online, despite that the scientific consensus is that no such link was ever established

“Science cannot explain how [Alzheimer’s disease] develops and, more important, [it] offers no effective treatment,” Theodore Lidsky, a researcher at New York State’s Institute for Basic Research in Developmental Disabilities writes. For this reason, Lidsky said, the aluminum hypothesis draws people in. It’s appealing, Lidsky said, because it’s nice to have a simple strategy for avoiding Alzheimer’s — but unfortunately, Alzheimer’s just isn’t that simple. Further, he added, “most scientists give little or no credence to this theory.”

Myth #2: “Diet soda increases the risk of dementia.”

Science says: Unproven.

A highly-criticized 2017 study linked diet soda to Alzheimer’s. It led to a flurry of clickbait articles suggesting you should ditch the diet soda.  

Without getting into the nuts and bolts of the statistical methods, scientists agree the study did not convincingly establish any link between diet soda and dementia. There is no credible, established evidence currently linking diet soda to dementia. 

Despite being linked to every disease under the sun, the artificial sweeteners in diet soda have been studied for decades, with dozens of studies supporting their overall safety as food additives. 

Myth #3: Alzheimer’s is a normal part of aging.

Science says: Inaccurate.

While people may become a little forgetful as they age, they can still form new memories and learn. People living with Alzheimer’s typically have deposits of certain proteins in their brains, alongside inflammation, and die-offs of brain cells. Despite common misconceptions, Alzheimer’s disease is not a normal part of the aging process

The idea that Alzheimer’s comes with aging isn’t just wrong — it can be harmful. While some (but not all) cognitive abilities do tend to decline a bit with age, studies have shown that even the simple act of reminding older adults about ageist ideas — like that older adults lose their mental sharpness and eventually experience neurodegenerative disease — can actually contribute to worsening memory problems. 

“Older adults should be careful not to buy into negative stereotypes about aging,” said Sarah Barber of the USC Davis School of Gerontology. “Attributing every forgetful moment to getting older can actually worsen memory problems.”

Myth #4: If your parent has dementia, you’ll eventually get it too.

Science says: False.

You can inherit genes that make dementia more likely. But, only five percent of Alzheimer’s cases are directly caused by specific genes, and other kinds of dementia aren’t definitively determined by genetics, either. For the rest of the cases, genetics is just one piece of a much larger puzzle. 

While a few genes substantially increase your chances of developing early-onset Alzheimer’s, Alzheimer’s, or other forms of dementia, scientists say it is impossible to know for absolute certain how genes will impact your brain health in the long run.


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