Sweet Poison: The Deadly Link Between Sugar and Dementia

How your favorite treats may be silently eroding your brain…

My mother died of Alzheimer’s. She was also a lifelong sugar junkie.

When we were kids, she used to make “healthy” treats for us by rolling two or three tablespoons of sugar up in a lettuce leaf to the shape of a cigar. Meals weren’t complete without dessert.

Alzheimer’s apparently has a few causes, including an apparent genetic component, but increasingly scientists are thinking it and other forms of dementia are, at their base, related to a warping of the body’s normal regulation of blood sugar, principally through the insulin our pancreases produce.

Recent research has revealed an alarming connection between sugar consumption and dementia, particularly Alzheimer’s disease. While our brains need glucose for energy, emerging studies have shown that excessive sugar intake may significantly increase the risk of cognitive decline and dementia.

The mechanisms behind this connection are complex and multifaceted. Scientists have discovered that consuming too much sugar can lead to insulin resistance, compromising the brain’s ability to effectively use glucose and potentially impairing cognitive function.

Additionally, high sugar intake triggers increased inflammation throughout the body, including the brain, contributing to various neurodegenerative diseases. Throughout my life, I’ve known that I can knock myself out at night by consuming a lot of sugar, even when it’s just dried fruit. (I suspect that drinking alcohol, which converts to sugar in the liver, does the same thing.)

Now, looking at the research, I’m wondering how much damage that may have done to my brain and if this is how my mom ended up where she was.

When excess sugar combines with proteins in the body, for example, it forms Advanced Glycation End Products (AGEs), which researchers have linked to the development of amyloid plaques—a hallmark characteristic of Alzheimer’s disease. High blood sugar levels can also damage blood vessels in the brain, reducing blood flow and oxygen supply to brain cells, which may lead to cognitive impairment.

The evidence supporting these concerns is substantial.

A 2024 study examining over 210,000 participants demonstrated that both absolute and relative increases in sugar intake significantly correlated with higher risks of all-cause dementia and Alzheimer’s disease. Research presented at the Alzheimer’s Association International Conference highlighted that higher consumption of sugary drinks was associated with increased Alzheimer’s risk.

The Harvard Medical School reports that even incremental increases in blood sugar levels corresponded with higher dementia risk, even in individuals without diabetes.

Different sugars appear to affect the brain in varying ways. Studies have identified fructose and sucrose as particularly problematic for dementia risk, while another large study focusing on women found that lactose showed a stronger correlation with Alzheimer's risk compared to other sugar types.

Experts recommend several practical approaches to reducing sugar intake. Limiting sugary beverages has become a primary focus, as research directly links these drinks to increased Alzheimer’s risk. Careful attention to nutrition labels, gradual reduction of sugar in recipes, and choosing whole foods over processed options can help decrease overall sugar consumption. Many processed foods contain hidden sugars, making awareness of ingredients crucial.

The Mediterranean diet and MIND diet have shown promise in supporting cognitive function. These eating patterns emphasize fresh fruits and vegetables, whole grains, lean proteins, and healthy fats like olive oil and nuts, while limiting processed foods and added sugars.

Healthcare professionals stress that while the relationship between sugar consumption and dementia risk continues to be studied, reducing sugar intake may benefit brain health.

In a recent article here in the Wisdom School, I noted that my physician has me on Metformin as an anti-aging drug (I am not diabetic). It principally down-regulates blood sugar, so I looked into the research between taking Metformin and a reduced risk of dementia or Alzheimer’s; what I found was amazing.

One study found that Metformin could reduce the incidence of dementia in diabetic patients by a full 34 percent. Another “study of 12,220 early terminators and 29,126 routine users of Metformin found that cessation of Metformin therapy without abnormal kidney function markers was associated with 1.21 times the hazard of dementia diagnosis.”

Making informed choices about sugar consumption and adopting a balanced, nutrient-rich diet along with appropriate medication to control blood sugar, particuarly in diabetic individuals, could be crucial steps in protecting cognitive health as we age.

While the evidence doesn’t suggest that sugar directly causes dementia, this growing body of research indicates that managing sugar intake — particulary simple sugars like in processed foods, candy, soft drinks, and dried fruit — could be an important factor in maintaining cognitive health.

I just wish I’d known this when my mom was still alive…