Type 3 Diabetes: A Link Between Insulin Resistance and Alzheimer's

Scientists are Making a Connection Between Alzheimer's and Diabetes 

In recent years, researchers have increasingly linked Alzheimer’s disease to insulin resistance, leading to the term “Type 3 Diabetes.” This concept suggests that Alzheimer's may be, at least in part, a metabolic disorder affecting the brain, much like diabetes affects the body. With growing evidence pointing to the role of insulin in cognitive function, the connection between Alzheimer’s and diabetes has gained traction among scientists and medical professionals.

At 7 Day Home Care, we recognize the importance of understanding these connections, especially for families caring for loved ones with Alzheimer’s. By exploring the origins of Type 3 Diabetes, the role of insulin resistance in brain health, and how this condition progresses, we aim to provide insights that can help in managing and possibly preventing cognitive decline.

The Origins of the Type 3 Diabetes Hypothesis

The idea that Alzheimer's disease and diabetes are linked emerged from observations that individuals with Type 2 Diabetes (T2D) have a higher risk of developing Alzheimer’s disease. However, the connection runs deeper than just a shared risk factor.

In 2005, researchers Suzanne de la Monte and Jack Wands at Brown University introduced the term Type 3 Diabetes, proposing that insulin resistance and insulin deficiency in the brain contribute directly to Alzheimer’s disease. Their research demonstrated that the brains of individuals with Alzheimer’s show impaired insulin signaling, which impacts neuron survival, cognitive function, and memory formation.

Unlike traditional diabetes, which primarily affects blood sugar regulation in the body, Type 3 Diabetes focuses on how insulin dysfunction in the brain contributes to neurodegeneration. This groundbreaking concept has reshaped how scientists view Alzheimer’s, positioning it as a disorder with both metabolic and neurodegenerative components.

Insulin Resistance and Brain Function

Insulin is essential for brain function. While it is widely known for its role in glucose metabolism, insulin also supports neurotransmitter regulation, memory formation, and synaptic plasticity. The brain relies on insulin to facilitate neuronal communication, maintain cognitive functions, and prevent the accumulation of beta-amyloid plaques, one of the hallmarks of Alzheimer’s disease.

How Insulin Works in the Brain

• Supports Synaptic Plasticity: Insulin strengthens synapses, allowing neurons to communicate effectively.
• Prevents Beta-Amyloid Accumulation: Insulin helps clear beta-amyloid plaques, which are toxic clusters of protein associated with Alzheimer’s.
• Regulates Inflammation: Insulin has anti-inflammatory properties that protect neurons from oxidative stress and degeneration.
• Promotes Neuron Survival: Insulin prevents neuron death by supporting energy metabolism and mitochondrial function.

When insulin resistance develops in the brain, these functions become impaired, leading to cognitive decline.

The Link Between Type 2 Diabetes and Alzheimer’s

• People with Type 2 Diabetes have a 50–100% higher risk of developing Alzheimer’s.
• High blood sugar levels contribute to inflammation and oxidative stress, damaging brain cells.
• Insulin resistance in the body often coincides with reduced insulin signaling in the brain, worsening cognitive impairment.
• Studies show that diabetics have higher beta-amyloid levels, further supporting the metabolic link between the two diseases.

This evidence suggests that Alzheimer’s could be a neurological manifestation of insulin resistance, justifying the label Type 3 Diabetes.

How Type 3 Diabetes Contributes to Alzheimer’s Disease

The progression of Alzheimer’s in the context of insulin resistance follows a predictable pattern. Chronic high blood sugar, inflammation, and impaired insulin function gradually damage the brain, leading to hallmark Alzheimer’s symptoms such as memory loss, confusion, and cognitive decline.

Key Mechanisms Driving Alzheimer’s in Type 3 Diabetes

1. Brain Insulin Resistance

When neurons become resistant to insulin, they can no longer efficiently process glucose, leading to energy deficits in the brain. As brain cells starve, cognitive functions decline.

2. Beta-Amyloid Plaque Accumulation

Insulin plays a role in clearing beta-amyloid plaques. When insulin signaling is impaired, these plaques accumulate, disrupting neural pathways and triggering Alzheimer’s symptoms.

3. Inflammation and Oxidative Stress

Chronic inflammation—a hallmark of both diabetes and Alzheimer’s—exacerbates brain cell damage. Excess glucose and insulin resistance trigger oxidative stress, leading to neuronal death.

4. Tau Protein Tangles

Another Alzheimer’s hallmark, tau tangles, forms when insulin resistance affects protein regulation in the brain. These tangles disrupt neural connections, further contributing to cognitive decline.

Prevention and Management Strategies

While there is no cure for Alzheimer’s, understanding the Type 3 Diabetes hypothesis allows for potential preventive measures. Managing blood sugar levels, improving insulin sensitivity, and adopting brain-healthy lifestyle habits can reduce the risk of cognitive decline.

1. Diet and Nutrition

• Low-Carb, Mediterranean, or Ketogenic Diets: These reduce insulin resistance and inflammation.
• Healthy Fats (Omega-3s): Found in fish, nuts, and seeds, they protect brain cells.
• Antioxidants (Vitamin C, E): Reduce oxidative stress in neurons.
• Fiber and Whole Foods: Help regulate blood sugar levels.

2. Exercise and Physical Activity

• Regular exercise improves insulin sensitivity and boosts brain-derived neurotrophic factor (BDNF), which supports neuron growth.
• Activities such as walking, strength training, and yoga benefit both metabolic and cognitive health.

3. Intermittent Fasting

• Fasting promotes autophagy, the process by which the body removes damaged cells, including those contributing to Alzheimer’s.
• It also helps regulate insulin levels, reducing brain insulin resistance.

4. Blood Sugar Control

• Monitoring glucose levels prevents insulin resistance from worsening.
• Medication (Metformin, GLP-1 agonists) may help manage blood sugar and improve cognitive outcomes.

5. Cognitive Stimulation and Social Engagement

• Engaging in puzzles, reading, and social activities helps maintain cognitive function.
• Lifelong learning and mental stimulation can delay the onset of Alzheimer’s symptoms.

6. Quality Sleep

• Poor sleep disrupts glucose metabolism and increases beta-amyloid buildup.
• 7–9 hours of sleep per night is essential for brain detoxification.

The term Type 3 Diabetes has transformed the way researchers and healthcare professionals understand Alzheimer’s disease. By recognizing that insulin resistance plays a critical role in cognitive decline, new avenues for prevention and treatment are emerging.

At 7 Day Home Care, we are committed to providing compassionate care and education for families navigating Alzheimer’s. Understanding the metabolic underpinnings of this disease empowers families to make informed choices about lifestyle, diet, and medical management—all of which can help improve quality of life.

The information provided in this article by 7 Day Home Care is for educational and informational purposes only and should not be interpreted as medical advice, diagnosis, or treatment. While we strive to present accurate and up-to-date research, Type 3 Diabetes is a developing area of study, and medical opinions may vary. Always consult with a qualified healthcare professional before making any decisions regarding your health, treatment options, or lifestyle changes. 7 Day Home Care does not assume responsibility for any consequences resulting from the use of this information.

If you or a loved one is experiencing cognitive decline, early intervention can make a difference. Contact 7 Day Home Care today to learn how our specialized care services can support your family in managing Alzheimer’s and related conditions. 7 Day Home Care is the leading provider of in-home care services under private pay, long term care insurance, catastrophic insurance, and workers compensation insurance in Manhattan,  Queens, Brooklyn, Nassau County, and Suffolk County, New York. To learn more about our person centered care and client - caregiver matching home care services, please call 516-408-0034 today.

Brian Callahan

7 Day Home Care