Blood Sugar Spikes After Meals Linked to Higher Alzheimer’s Risk, New Study Finds

People who experience blood sugar spikes in the hours after eating could face a significantly higher risk of developing Alzheimer’s disease, according to groundbreaking new research led by the University of Liverpool.

The comprehensive study, published in the journal Diabetes, Obesity and Metabolism, analyzed genetic data from more than 350,000 individuals aged 40 to 69 from the UK Biobank. Researchers examined genetic markers linked to how the body processes sugar and used a technique called Mendelian randomisation to compare disease rates among those genetically predisposed to higher blood glucose levels.

Their findings were striking: individuals with elevated blood sugar two hours after eating—a condition known as postprandial hyperglycemia—were 69% more likely to develop Alzheimer’s disease. Surprisingly, other markers of glucose regulation, including fasting glucose, fasting insulin, and measures of insulin resistance, were not significantly associated with Alzheimer’s risk.

“This finding could help shape future prevention strategies, highlighting the importance of managing blood sugar not just overall, but specifically after meals,” explained lead author Dr. Andrew Mason in the study press release.

The research builds upon a growing body of evidence connecting metabolic health to brain function. Tanya Freirich, a registered dietitian and certified diabetes care and education specialist in North Carolina, noted that the findings align with previous research on the subject.

“Over time, high blood sugars damage blood vessels in the brain, which increases the risk of memory and learning problems,” Freirich told Fox News Digital. “The brain is dependent on glucose for fuel, so any restriction of that source due to damaged blood vessels can further harm the brain’s functional connectivity. Excess glucose also impairs our brain’s functioning.”

New Jersey-based registered dietitian Erin Palinski-Wade observed that the study points to postprandial glucose control as a potential target for protecting brain health. “This study suggests that when it comes to brain health, it’s not just whether someone has diabetes that matters, it’s how high blood sugar rises in the two hours after eating,” she explained.

“Interestingly, traditional fasting glucose and insulin levels were not linked to Alzheimer’s risk, which suggests we may be missing part of the picture if we only focus on fasting labs and overlook what happens after meals,” Palinski-Wade added.

The research team acknowledged several limitations to their findings. The link between blood glucose spikes and dementia outcome wasn’t confirmed in a separate Alzheimer’s genetic dataset, raising questions about the applicability of the findings to wider populations. Additionally, the UK Biobank participants tended to be healthier, predominantly White British individuals, potentially limiting the study’s generalizability.

“We first need to replicate these results in other populations and ancestries to confirm the link and better understand the underlying biology,” noted senior author Dr. Vicky Garfield. There’s also a risk that some dementia diagnoses were inaccurate or missed entirely, as the study relied on medical records and self-reporting.

If validated through additional research, the study could open new avenues for reducing dementia risk, particularly in people with diabetes or those genetically predisposed to blood sugar regulation issues.

Health experts emphasize that while genetic factors play a role in how the body processes sugar, dietary choices and lifestyle habits can significantly impact blood sugar levels. Freirich recommends eating balanced meals that include vegetables, protein, and complex carbohydrates, while reducing intake of excess sugar and choosing whole grains instead of refined ones.

“Fiber is helpful for improving blood sugar stability, but is also beneficial for heart health, digestion, and reducing inflammation, all of which contribute to improved brain health,” Freirich explained. She advises aiming for 25 to 35 grams of fiber daily and limiting sodas, juices, sugar-sweetened beverages, and desserts.

Physical activity also plays a crucial role in blood sugar management. “A short burst of activity after eating, such as a walk, can also help lower your blood sugar spike after eating,” Freirich said.

For those concerned about their blood sugar levels, experts recommend consulting with a healthcare provider about appropriate testing to assess personal risk and develop tailored prevention strategies.