In recent years, researchers have been actively trying to understand what causes Alzheimer’s and specifically the role that diabetes plays in it. While doctors have known for years that Alzheimer’s and diabetes go hand in hand, scientists have only more recently discovered the changes that occur in the brain when a person develops diabetes.

Let’s look further at the connection between Alzheimer’s and diabetes.

What is Diabetes?

Up to 80% of Alzheimer’s patients have type 2 diabetes or insulin resistance.

Diabetes is a chronic condition that is caused when you don’t have enough insulin or your body doesn’t properly use the insulin you have.

We need sugar—in the form of glucose—for energy. When we eat carbohydrates, they are converted to glucose which is absorbed into the bloodstream. Glucose is the fuel that powers the cells in our bodies. Insulin is a hormone that helps your cells absorb and process glucose.

When glucose levels go up in your blood, more insulin is produced. However, consistently high levels of glucose (from eating too many or the wrong type of carbohydrates) can lead to insulin resistance.

With lots of sugar in your blood, lots of insulin is produced. Eventually, your cells get numb to the insulin and stop taking in and processing all the glucose. This is called insulin resistance and first leads to prediabetes and if not controlled, to type 2 diabetes.

Insulin Resistance in the Brain—Alzheimer’s and Diabetes

Your brain needs glucose. In fact, half the energy you consume goes toward powering your brain. Without enough glucose, neurons don’t transmit messages properly and you may begin to have memory problems. After a while, parts of the brain will shrink and dementia may develop.

Just like the other cells in your body, your brain cells can become insulin resistant, preventing their ability to absorb and process glucose. The cells starve and die without energy, leading to dementia or Alzheimer’s.

Factors that Increase Your Risk of Alzheimer’s and Diabetes

Because Alzheimer’s and diabetes are so closely linked, there are risk factors for developing both of them. By managing the conditions and factors listed below, you can reduce your chances of developing diabetes and potentially Alzheimer’s.


Long before being diagnosed with diabetes, there are warning signs in your blood.

Your blood sugar levels may be high, but not yet in the diabetic range—prediabetic. This indicates that you are starting to develop insulin resistance or not producing enough insulin.

Prediabetes is a warning sign that you need to make some lifestyle changes and get your blood sugar under control. It can lead to both diabetes and Alzheimer’s.


Obesity is the leading cause of type 2 diabetes. Nearly 90% of people diagnosed with diabetes are overweight or obese.

While not every person who is overweight will develop diabetes, obese people are 6 times more likely to develop it.

Physical Inactivity

People who are not physically active or who have a sedentary lifestyle have an increased risk of developing type 2 diabetes and Alzheimer’s.

Exercise—or the lack of it—affects your body’s ability to process glucose. Physical activity helps prevent insulin resistance because it increases the amount of glucose your cells can take in by at least 40%.

Exercise also reduces inflammation in your body. Inflammation has been linked to both Alzheimer’s and diabetes.

Alzheimer's and Diabetes

How to Lower Your Risk of Alzheimer’s and Diabetes

Type 2 Diabetes and Alzheimer’s can be prevented by making healthy lifestyle decisions.

Watch Your Blood Sugar Levels

If your doctor tells you that you have high blood sugar levels or that you are prediabetic, there’s no time to waste. Take control of your blood sugar level through diet and exercise and by managing your weight. banner

If prediabetes is allowed to progress, you’ll end up with insulin resistance which greatly increases your risk of Alzheimer’s and diabetes. Preventing insulin resistance is a key factor in the prevention of them both.


Experts recommend at least 150 minutes of physical activity per week at a moderate intensity. You’ll know if you’re working out at a high enough intensity if it feels a bit hard but not exhausting. A brisk walk (around four miles per hour), dancing, or swimming are some examples.

Ideally, you’ll want to exercise at least 30 minutes almost every day. Exercise can lower inflammation and help you control glucose levels in your blood and your weight—all important things to lower your risk for Alzheimer’s and diabetes.

Make Changes to Your Diet

You are what you eat and in the case of Alzheimer’s and diabetes, you’ll want to watch your calories and your carbohydrates.

Watch Your Calories

If you’re currently at a healthy weight, you’ll want to be careful to maintain it. But if you are overweight, researchers recommend eating 500-600 fewer calories each day which can have a positive effect on your blood sugar levels (and your weight!)

Also, when you eat is important. Eat more of your calories in the first half of the day—with an emphasis on breakfast—and fewer calories later on to reduce insulin resistance.

Eat the Right Types of Carbs

Carbohydrates include sugar, starches, and fiber. To help control your blood sugar, prevent insulin resistance, and reduce your risk of Alzheimer’s and diabetes make good choices about the types of carbs you eat.

The best kinds of carbs are whole and unprocessed non-starchy organic vegetables. These vegetables have lots of fiber and don’t cause spikes in your blood glucose.

Non-starchy vegetables to look for:

  • Lettuce
  • Broccoli
  • Carrots
  • Cucumbers
  • Tomatoes
  • Peppers
  • Green beans

Nutrient-dense starchy carbohydrates are fine to have in smaller amounts. Choose whole and minimally processed organic fresh fruits and vegetables as well as wild and intact grains.

Starchy carbs you can eat in moderation:

  • Fruits such as blueberries, strawberries, and apples
  • Vegetables such as peas, sweet potatoes, and corn,
  • Whole grains such as oatmeal, quinoa, barley, brown rice, and whole wheat bread and pasta
  • Beans and lentils such as kidney or black beans and chickpeas

Avoid Highly-Processed Refined Foods

Foods that are highly processed and have lots of salt, sugar, fats, and artificial sweeteners should be removed from your diet, or eaten very infrequently. They are often high in calories leading to weight gain and cause large spikes in your blood sugar which results in developing insulin resistance.

Avoid fried foods, baked goods, ice cream, candy, prepackaged snacks, white bread and rice, sugary cereal, and sugary drinks such as juice, sweet tea, and soda.

Lose Weight

Keeping a healthy weight is a critical factor in your overall health, but especially for preventing Alzheimer’s and diabetes.

People who are obese are 31% more likely to develop dementia and 6 times more likely to develop diabetes.

Losing just 7% of your body weight greatly reduces your risk of developing diabetes. If you weigh 175 pounds, that means losing just 12 pounds can cut your risk by nearly 60%.

Summing Up Alzheimer’s and Diabetes

Much of the recent research is clarifying the role that diabetes plays in the development of Alzheimer’s. While we can’t yet say that diabetes causes Alzheimer’s we do know that the two are very closely linked.

Insulin resistance is a key factor in both Alzheimer’s and diabetes—preventing insulin resistance is critical to preventing both.

Want more advice on keeping your brain healthy? Read our series on the best diet for preventing Alzheimer’s and lifestyle tips for brain health.

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