The Link Between Hyperglycemia and Dementia, a New Study

A new research, published in the medical journal Diabetes, Obesity and Metabolism, suggests that high blood sugar levels (not only diabetes, but also prediabetes) seem to be linked to an increased risk of developing cognitive impairment and dementia.

Conversely, the authors of the study, researchers at University College London and the London School of Hygiene & Tropical Medicine, noted that lower blood sugar levels can be beneficial to brain health.

The Link Between Hyperglycemia and Dementia, a New Study

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  • High blood sugar levels can cause cognitive impairment and dementia because they increase inflammation in the brain area.
  • Both people with diabetes and those with prediabetes have a higher risk of developing this condition.
  • Maintaining a healthy weight, eating a healthy diet, exercising, and not smoking are recommended in order to control blood sugar levels.

The researchers also noted that hyperglycemia is more strongly associated with vascular dementia, compared to other forms of dementia and Alzheimer's disease. In addition, antihypertensive medication was highlighted as a factor in this association.

While it has long been known that diagnosed diabetes, for several complex reasons that are not yet fully understood, is linked to declining brain health in old age, experts note that the study is especially relevant as it could prove that any sustained high blood sugar levels (as is the case with prediabetes) can be dangerous to brain health.

It is even believed that people with prediabetes may have a higher risk in the long term compared to those who have been diagnosed with diabetes. The reason behind this is that while blood sugar levels in people with prediabetes are causing health issues, these patients are rarely being monitored or receiving adequate therapeutic care.

Why does this happen? There is still no clear answer, but it is believed that high blood glucose levels, even those that are episodic and non-chronic, cause sugar metabolites to build up inside the brain cells, resulting in systemic inflammation and damage to cell membranes.

Strategies to Control Sugar Levels

This research provides new evidence on the significance of monitoring blood sugar levels in order to intervene at an early stage and prevent brain damage, which can sometimes be irreversible. To monitor blood sugar levels, experts recommend:

Maintaining a Healthy Weight

Being overweight, especially when the weight is distributed in the abdominal area, increases the risk of developing type 2 diabetes. Specialists recommend losing between 5 and 10% of the excess weight, not gaining it back, and maintaining this goal long-term. This can also prevent other types of health issues.

Eating Healthy

Eating the right foods helps you control your blood glucose level and lose excess weight. Among the best options are:

  • Fruits and vegetables: Citrus, berries, apples, pineapples, grapes, kiwis, green leafy vegetables, such as chard, spinach, broccoli or kale, and other non-starchy options.
  • Fiber: Herbs and spices, such as coriander or oregano; legumes, such as lentils, peas, peanuts, and beans; or fruits and cereals.
  • Healthy fats: Fish, such as tuna, mackerel, salmon, sardine and trout; flaxseed or flaxseed oil; nuts; chia seeds; canola, olive, or soybean oils; and avocado.

Just as some foods are beneficial in preventing diabetes, others can cause it or make it worse. It is recommended to avoid eating:

  • Added sugars (usually found in processed foods).
  • Refined products, such as flour or white rice.
  • Soft drinks, sodas or processed juices.
  • Red meat, especially processed meat, and cold meats.


Physical activity serves a double purpose, since it increases the body's consumption of glucose and stimulates muscle fibers, facilitating the transport of sugar inside the cells. Although all types of exercises help to prevent type 2 diabetes, the greatest benefits come from exercising at a moderate intensity level.

Avoiding Tobacco Use

Nicotine and certain chemicals found in cigarettes damage cells, cause inflammation, affect insulin response, and increase the risk of increased abdominal fat, which are all risk factors for type 2 diabetes.

Sources cited: American Diabetes Association, United States National Library of Medicine, Mayo Clinic, National Institute of Diabetes and Digestive and Kidney Diseases.

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