Eye Opening Facts on the Effects of Diabetes on the Brain!!

We know that uncontrolled diabetes can negatively affect several major organs like the heart, eyes, and kidneys. But can diabetes have an affect on your brain and cognition? Keep reading to know more about the effects of diabetes on the brain.

Our brain is responsible for the way we process things and make sense of the world. In simple terms, it helps carry out various functions, conscious and unconscious. But what happens if your brain function is hampered by other health conditions? For instance, what are the effects of diabetes on the brain? In this article, we discuss how your blood sugar levels affect your cognition, the cerebrovascular effects of diabetes, and how to prevent neurological complications.




How Does Diabetes Affect the Brain?

Type 2 Diabetes is a condition characterised by insulin resistance in your cells, which causes high blood glucose levels. Glucose (sugar) is the main source of energy for the cells in your body.


Your brain consumes about 20 to 25% of all the energy produced from glucose, as it is rich in neurons (nerve cells) that require a large amount of energy to function. Thus, any change in blood glucose levels can have a major impact on your brain function and cognition.


Let’s find out in detail how the brain is affected by high and low blood glucose levels.



Since the brain is fueled by glucose, you may assume that high blood glucose levels or hyperglycaemia may be beneficial for your brain health. This could not be further from the truth. High blood glucose levels can lead to inflammation, which can alter your brain function.


Over time, frequent episodes of hyperglycaemia and excessive blood sugar can cause damage to the arteries that supply blood to your brain, as well as your brain cells. Thus, the effects of diabetes and hyperglycaemia on the brain may be undetectable initially, but can lead to a gradual decrease in blood supply to the brain, which may result in the death of cells and tissue in the brain. This is known as brain atrophy.


Decreased blood supply to the brain may result in the development of symptoms like memory issues, problems with thinking and reasoning, poor judgement, change in behaviour and temperament, and issues with speech, confusion, etc. that develop over years.



Unlike hyperglycaemia, the effects of low blood glucose levels or hypoglycaemia on the brain are immediate. Low glucose levels in your blood can result in reduced oxygen and blood supply to your organs, especially your brain. This can result in headaches, dizziness, irritability, trouble concentrating, and confusion in mild cases.


Severe cases of hypoglycaemia can cause loss of consciousness, seizures and coma. Hypoglycaemia can also cause depression and memory loss in the long term.


What are the Neurological Complications of Uncontrolled Diabetes?

Uncontrolled diabetes and fluctuating blood glucose levels can cause nerve and brain disorders in the long term. Your risk of developing cerebrovascular or neurological complications of diabetes increases the longer you have the condition. 


The following are some of the disorders that can be caused by unchecked Type 2 Diabetes:


Cognitive Impairment

High or low blood sugar levels can negatively affect your cognition and cause issues with thinking, reasoning, learning, judgement, concentration, and memory. The resulting lack of mental clarity, inability to focus, confusion, and memory issues are often referred to as brain fog. Brain fog or mental fog can give a feeling of being less aware of your surroundings or being “cloudy-headed”.


Brain fog is not a medical condition, but a term used to describe the symptoms of cognitive impairment. Some common brain fog symptoms include:

  • Increased irritability
  • Feeling confused or “spacy”
  • Trouble speaking or finding the right words
  • Feeling lethargic
  • Inability to focus
  • Difficulty in reasoning or solving problems
  • Memory loss


Cognitive impairment is not necessarily accompanied by brain or nerve damage, and can be managed with good glycaemic control, diet, exercise, sleep, and medications.



Vascular Dementia

High blood sugar levels can damage the blood vessels that supply oxygen and nutrients to your brain. The resulting impairment in blood flow can cause brain damage, which can sometimes lead to a condition called vascular dementia.


Dementia can cause problems with memory, reasoning, judgement, planning, and other cognitive functions. Vascular dementia cannot be reversed. However, its progression can be prevented and the condition can be effectively managed with good glycaemic control and medications that prevent strokes.


Alzheimer’s Disease

Alzheimer’s disease is a degenerative disorder of the brain that is a major cause of dementia. Some scientists have referred to Alzheimer’s as Type 3 Diabetes and hypothesised that Type 2 Diabetes could be a direct cause of Alzheimer’s disease.


The reasoning behind this hypothesis is that increased insulin levels and insulin resistance in the brain can lead to the abnormal accumulation of protein (amyloid plaques and neurofibrillary tangles) in your neurons. These amyloid plaques and neurofibrillary tangles are characteristic clinical features of Alzheimer’s disease.


Diabetic Neuropathy

Uncontrolled high blood sugar levels can damage your nerves, leading to a condition called diabetic neuropathy. Damaged nerve cells are unable to relay messages to the brain properly. Diabetic neuropathy is a common complication in most diabetics and can lead to severe pain and disability, if left untreated.


The condition most commonly affects the nerves in your limbs, causing tingling, pain, numbness, and/or loss of sensation in your feet, legs, and arms. Damage to the nerves that affect the heart rate, digestive system, reproductive system, urinary tract, etc. can cause issues like fluctuations in blood pressure level, nausea, constipation, bladder or bowel control problems, vaginal dryness in women, erectile dysfunction in men, and more.


Diabetic neuropathy can be managed or prevented with good glycaemic control and healthy lifestyle changes.


How Can You Prevent or Manage the Adverse Effects of Diabetes on Your Brain?

The nerve and brain damage caused by diabetes and high blood sugar levels are irreversible. However, the cognitive impairment, nerve damage, and brain disorders caused by diabetes can be prevented or managed effectively through the following means:

  • Ensure that your blood sugar levels are within the normal range (HbA1c < 7%, random blood sugar levels between 70 mg/dL and 140 mg/dL).
  • Follow a diabetic-friendly meal plan.
  • Get at least 30 minutes of moderate-intensity exercise every day.
  • Maintain a healthy weight (BMI between 18 kg/m2 and 25 kg/m2).
  • Sleep for at least 7 hours every night.
  • Learn to cope with stress in a healthy way, such as by doing yoga and meditation. 
  • Quit smoking.
  • Limit your alcohol consumption.
  • Take all your medications as prescribed.
  • Keep all your appointments with your doctor and get regular health checkups.


When to See a Doctor?

You should consult a doctor if you are experiencing any of the following symptoms frequently, and if they are affecting your daily life:

  • Confusion
  • Irritability
  • Dizziness or fainting
  • Trouble with speech, talking, or language
  • Issues with concentration
  • Pain, numbness, tingling, or loss of sensation in your limbs 


Don’t Have Time To Read?

  • The insulin resistance and abnormal blood sugar levels that are characteristics of Type 2 Diabetes can cause inflammation and damage to the cells and blood vessels in your brain.
  • Your brain requires glucose to function normally. Thus, any fluctuation in your blood glucose levels can affect your cognition and brain function.
  • Hyperglycaemia can damage the blood vessels in your brain, leading to a decreased blood supply.
  • High blood sugar levels can also damage the neurons or cells in your brain, resulting in cognitive issues like trouble concentrating, speaking, reasoning, confusion, and memory loss.
  • Hypoglycaemia can hamper blood and oxygen supply to your brain, leading to issues like dizziness, confusion, irritability, fainting, seizures, or a coma.
  • Uncontrolled diabetes can lead to cognitive issues or brain fog, dementia, and neurological complications like diabetic neuropathy.
  • Cognitive impairment caused by inflammation in the brain may be reversed with good glycaemic control and lifestyle changes.
  • Damage to brain cells or tissues and blood vessels cannot be repaired or reversed. However, the progression of damage can be halted with good glycaemic control, a diabetic-friendly diet, regular exercise, stress management, good sleep, quitting smoking, limiting alcohol consumption, taking your medication as prescribed, and frequent health check-ups.
  • Use the Phable Care App to consult India’s leading diabetologists, order medicines, book lab tests, integrate blood sugar monitoring and other devices to get real-time remote care from the comfort of your home. Also, check out our Diabetes Management program which provides ‎360º care. Let’s treat diabetes together.

Friendly Asked Questions

What are the brain issues associated with diabetes?

High or low blood sugar levels caused by diabetes can lead to cognitive issues like confusion, irritability, memory loss, trouble with reasoning and thinking, speech problems, etc. Long-term high blood sugar levels can lead to brain damage, which can cause conditions like dementia.

Is diabetic brain damage reversible?

High blood sugar levels can initially cause inflammation in your brain, which can lead to cognitive problems. This inflammation and the consequent issues can be reversed by bringing down your blood sugar levels to normal and maintaining them as such. However, long-term high blood sugar levels can damage the arteries that supply blood to your brain, as well as the neurons in your brain. Your brain cells and blood vessels, once damaged, cannot be repaired.

Does diabetes cause mental confusion?

Yes, high or low blood sugar levels can lead to problems like memory loss, confusion, trouble with speech and thinking, lack of concentration, etc. This is caused by an imbalance in the blood glucose and oxygen supply to your brain.

Can diabetes affect your memory?

Yes, diabetes can lead to inflammation and damage to the brain cells and the arteries that supply blood to your brain. This can lead to the death of brain tissue, which can cause problems with your memory.

What is the link between diabetes and dementia?

Diabetes and high blood sugar levels can damage the blood vessels in your brain and cut off blood supply to your neurons. This can lead to a condition called vascular dementia, which can affect your memory and cognition.

Are diabetics more prone to dementia?

Yes, studies suggest that one of the negative effects of diabetes on the brain is an  increased chance of developing dementia. The longer you have diabetes, the higher your risk is for dementia. 

What causes brain fog in diabetes?

Fluctuating blood sugar levels and damage to the cells and arteries in the brain can cause brain fog.