Diabetes and Your Brain: Why Blood Sugar Matters

• Your brain is sensitive to how much glucose (sugar) it gets.
• Both high and low blood sugar can damage blood vessels in the brain.
• Keeping blood sugar close to target helps prevent problems.

Diabetes can damage blood vessels in the brain and cause a stroke or memory loss. CDC.

The diabetes–brain connection

Your brain is your body's command center, and it runs on blood sugar — it is the most energy-hungry organ, using half of all the sugar energy in the body. When blood sugar moves outside your normal range, it throws the command center off balance. Just as diabetes can damage nerves elsewhere, it can damage nerves in the brain.

That can bring problems with memory and learning, mood shifts, weight gain and hormonal changes — and over time more serious problems such as Alzheimer's disease. Both high and low blood sugar can do this.

High blood sugar

Frequent hyperglycemia stresses the brain, slowly and invisibly — people often don't know it's happening. Over time it damages the blood vessels that bring oxygen-rich blood; with too little blood, brain cells die. That can cause memory and thinking problems and eventually vascular dementia.

Low blood sugar

Hypoglycemia — blood sugar below 70 mg/dL — can be very dangerous if untreated. A brain short of sugar is also short of oxygen, and unlike high blood sugar, the signs are often immediate:

• feeling dizzy, shaky or irritable;
• trouble walking or talking;
• when severe, passing out, seizures or coma.

Some people have no symptoms, so check your blood sugar often to catch lows early. Some research links big dips to depression, memory and attention problems. If you have these and frequent lows, your doctor can find out why, adjust your medicine, or refer you to a mental health counselor.

Protecting your brain

Your doctor will set a personal target range. To stay in it and support brain health:

• follow a healthy eating plan rich in vegetables, fiber and fruit;
• keep a healthy weight;
• get regular physical activity;
• take medicine as prescribed;
• stop smoking;
• manage stress.

Sources

Based on "Your Brain and Diabetes," Centers for Disease Control and Prevention; a work of the United States government in the public domain. A stock photograph is left out.