What Is Type 3 Diabetes? Insulin Resistance In The Brain That Could Trigger Alzheimer’s
Most people are aware of type 1 and type 2 diabetes, but did you know there is a type 3 diabetes as well! It is a more obscure term. Although it is not an accepted medical diagnosis, type 3 diabetes has been discussed in the literature as a possible relationship between insulin resistance in the brain and Alzheimer's disease. This link has been described to help explain how metabolic disorders impact brain health, causing cognitive decline and dementia.
Type 3 diabetes is more of a misnomer because it should not be confused with type 3c diabetes, which relates to pancreatic dysfunction. The term "type 3 diabetes," on the other hand, has been loosely used by some scientists to analogously propose that Alzheimer's disease is strongly implicated with insulin resistance in the brain.
This concept was conceptualized by Dr. Suzanne de la Monte and Dr. Jack Wands of Brown University in the year 2008. This hypothesis postulated that Alzheimer's disease may be called type 3 diabetes for it bears many similarities with glucose metabolism disorder type 2 diabetes. Their concept arises from the basic principle that insulin is fundamental to blood sugar regulation, but it is also the case with the brain. When brain cells become insulin-resistant, they lose access to glucose, impairing their function.
Research published in the Journal of Diabetes Science and Technology supports this hypothesis by indicating that insulin resistance can be a significant contributor to the occurrence of dementia, also referred to as Alzheimer's. The symptoms of memory loss and diminished reasoning are associated with impaired glucose metabolism in the body, especially in the cerebral tissue.
Although type 3 diabetes is not a "medical term," its symptoms correlate well with Alzheimer's diseases that are known to reduce the ability to think in an efficient manner and bring down brain health. These signs are:
- Loss of memory, especially short-term.
- Poor judgment and judgment ability
- Failure in recognizing people or places familiar once.
- Failure in the process of reading, writing or processing numbers
- Anxiety, agitation, or mood changes.
- Disorganized thoughts or confusion
- Lack of impulse control
As the disease advances, patients may be afflicted with severe complications including an inability to swallow or control their bodily functions. In the final stages, most patients die from fatal complications such as aspiration pneumonia.
This may not be well understood with regards to type 3 diabetes, or the exact link between insulin resistance and Alzheimer's disease. Some identified contributing factors include the following:
Insulin acts as an important regulatory mechanism of brain functions such as memory and cognition. The reduction in insulin signaling may impair metabolism of brain cells, thus bringing about neurodegeneration.
These diseases show a strong relationship and those individuals diagnosed with type 2 diabetes have double chances of getting Alzheimer's. In the two, the main causes can be chronic inflammation, oxidative stress, and a defect in glucose metabolism.
Insulin resistance associated with obesity, stress, and an unhealthy diet is considered a cause that may increase the chances of Alzheimer's disease.
Researches in Frontiers in Neuroscience and The Lancet Neurology have also highlighted that drugs used for antidiabetic medication may be crucial for the prevention or at least slowing down the course of Alzheimer's.
In 2022, in a study in Pharmaceuticals, researchers studied biomarker uptake in brain regions implicated in the faulty uptake and metabolism of blood sugar in Alzheimer’s patients.
Emerging Therapies
Research into such treatments as intranasal insulin has also been promising. Intranasal delivery of insulin directly to the brain has been reported to enhance glucose uptake by brain cells, improve memory, and boost cognitive performance. While such clinical trials have been shown to be successful, additional research is needed for safety and efficacy.
Medications
For patients being aggressive or agitated, antipsychotic drugs may be prescribed; however, therapies such as cognitive rehabilitation as well as cognitive stimulation therapy serve to preserve memory and executive function.
Lifestyle Interventions
Diet, exercise, and stress management are critical in preventing and managing insulin resistance. A review in the Journal of Alzheimer's Disease also highlighted the benefits of Kirtan Kriya meditation, which can regulate genes involved in insulin and glucose metabolism, improve sleep, and reduce inflammation.
Although type 3 diabetes is not officially recognized, its connection to Alzheimer’s disease underscores the importance of proactive measures for brain health. Some prevention strategies include:
1. Healthy Diet
Consuming a balanced diet rich in antioxidants, whole grains, and healthy fats may support brain health.
2. Regular Exercise
Physical activity improves insulin sensitivity, reduces inflammation, and enhances overall metabolic health.
3. Stress Reduction
Mindfulness practices, including meditation, have been shown to lower stress levels, which can reduce the risk of cognitive decline.
The term type 3 diabetes brings out the complex relationship between metabolic disorders and brain health. Even though it is not a recognized medical condition, the concept emphasizes the crucial role of insulin in brain function and its possible contribution to Alzheimer's disease. Continued research will hopefully provide hope for therapies such as intranasal insulin and lifestyle modifications.
Credit: The Jenny McCarthy Wahlberg Show/Youtube
Actress Jenny McCarthy has opened up about the lasting effects of her battle with mold poisoning, revealing that the experience has left her with post-traumatic stress disorder (PTSD), anxiety and a fear of being exposed to mold again.
During a recent episode of her podcast, The Jenny McCarthy-Wahlberg Show, the actress spoke about the physical and emotional toll of the illness, the extensive measures she has taken to avoid further exposure and her ongoing recovery.
McCarthy said she had to discard most of her belongings after the suspected exposure, including her clothes and furniture.
"I wound up throwing everything away," she said, adding that she and her husband, Donnie Wahlberg, also left their furniture behind when they moved out of their Los Angeles home.
Although she believes the exposure may have originated in her makeup room, she said she did not want to take any chances.
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McCarthy said the experience made her fearful of encountering mold wherever she went. She described having histamine reactions in different places and struggling with everyday activities, including travelling in Ubers, visiting restaurants and boarding airplanes.
The actress also revealed that the prolonged health struggles contributed to a nervous breakdown, leaving her husband worried about her well-being.
Having undergone 11 surgeries in 15 months, McCarthy said she became increasingly afraid that her body would start "falling apart again."
She also described the emotional strain of her treatment, which involved taking around 100 pills a day.
"I find myself crying sometimes," she said, describing how difficult it was to manage the medication and the uncertainty surrounding her recovery.
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McCarthy first spoke publicly about her health ordeal in March, describing six months of what she called "living hell."
She previously reported experiencing an infected root canal, pus-filled growths on her eyelids, mouth infections, tooth pain, skin rashes and food allergies.
The actress said a doctor diagnosed her with mycotoxin poisoning in December 2025. She has since described being in remission for seven months and focusing on recovery.
Her efforts to avoid further exposure have also been extensive. In an October 29 podcast episode, she revealed that she had been sleeping in a tent in her backyard because she was afraid of being exposed to mold indoors.
"Because I am paranoid now about basically sleeping anywhere, I live in a tent," she said.
McCarthy has also spoken about concerns over her breast implants and whether they could be associated with mold exposure. During a November 3 podcast episode, she discussed the issue with plastic surgeon Dr Terry Dubrow, who has treated her previously.
Mycotoxins are toxic substances produced by certain molds and other fungi. Exposure can occur through contaminated food or environments, depending on the type of toxin and the route of exposure.
According to the Cleveland Clinic, mycotoxin exposure can affect different parts of the body, including the digestive system, eyes and mouth. Mold exposure can also trigger allergic reactions and worsen respiratory conditions such as asthma.
The health effects depend on factors such as the type of mycotoxin, the amount and duration of exposure, and an individual's susceptibility.
Credit: AI image
In a bizarre medical case, a 28-year-old US man began seeing his pet cat Luna’s features on human faces after brain surgery. These included almond-shaped eye sockets enlarged pupils and stripes.
If Karl sees Luna first thing in the morning, he continues to see her features on human faces throughout the day, whether in person or online.
However, if he wakes up looking at a human face, he may see that person’s pupils and eye shape on other people’s faces and even on his cat.
According to a case report published in the journal Cortex, Karl experiences a form of palinopsia, in which something seen earlier persists or reappears in subsequent perception. In his case, this causes facial distortions known as prosopometamorphopsia (PMO).
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Karl, who lives in the northeastern US, has experienced the condition for two years. It began after surgery to remove part of his right temporal lobe to treat an arteriovenous malformation (AVM), an abnormal tangle of blood vessels connecting arteries and veins that can cause bleeding in the brain.
The right temporal lobe plays an important role in face processing.
"This case of Karl seeing his cat's features in human faces and vice versa demonstrates that individual features can be pulled from memory and influence our ongoing perception," said lead author Brad Duchaine, professor and chair of psychological and brain sciences and principal investigator of the Social Perception Lab at Dartmouth.
Karl is not alone. According to Duchaine's lab, more than 250 people experience facial distortions. Many are mistakenly diagnosed with psychiatric problems.
"We have heard from people who have been told that they had a psychiatric problem and, in some cases, have even been put on antipsychotics, when they are in fact just having visual problems," Duchaine said.
Duchaine also cited a 1986 study published in Cortex. It described a woman who saw a poodle sitting on a passenger's lap while riding a bus. She then began seeing the poodle's face on every passenger. The woman had experienced a stroke nine months earlier.
Unlike that case, Karl sees individual facial features transferred between faces rather than entire faces.
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Duchaine used a large language model to turn a line drawing of Karl’s experience into a photorealistic image. He then worked with Karl to refine the visuals featured in the report.
AI-generated images can help researchers understand visual distortions and help patients explain their experiences to doctors, friends and family, Duchaine said, adding that he will continue working with Karl to decode more about the condition.
Prosopometamorphopsia (PMO) is a rare visual condition in which faces or facial features appear distorted due to changes in the brain's face-processing network. The term combines prosopo (Greek for face) and metamorphopsia (perceptual distortion).
People with PMO may see facial features as:
Two prominent subtypes are:
Most cases last days or weeks, although some persist for years. Around 75 case reports have so far been published.
Credit: iStock
Rubbing your eyes is a common habit, often triggered by itching, dryness or tiredness. However, frequent and vigorous rubbing can damage the cornea and increase the risk of keratoconus, a progressive condition that causes it to thin and bulge outward, experts warn.
World Keratoconus Day is observed every year on November 10 to raise awareness about the condition.
Early diagnosis is important to slow its progression. Frequent changes in spectacle prescriptions or deteriorating vision should prompt an eye examination.
Frequent or aggressive eye rubbing can put mechanical stress on the cornea, potentially weakening its structure and worsening existing eye conditions.
Speaking to HealthandMe, Dr Janhvi Mehta, Consultant Ophthalmologist, Jaslok Hospital and Research Centre, Mumbai, said, "Frequent or vigorous eye rubbing can damage the cornea, particularly by contributing to keratoconus. It can also cause corneal epithelial injury and worsen existing ocular allergy."
Repeated rubbing can:
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Dr Mahipal Singh Sachdev, Chairman and Managing Director, Centre for Sight Group of Hospitals, explained that excessive rubbing puts pressure on the cornea and can damage its collagen structure.
"The cornea might become thinner than usual or its shape may become uneven, leading to impaired vision. Hence, people should avoid the habit of rubbing their eyes," he told HealthandMe.
Children with allergies, especially allergic conjunctivitis, may be more vulnerable to keratoconus because of frequent eye rubbing.
Allergies can cause persistent itching, redness, watering, and discomfort, encouraging children to rub their eyes repeatedly. The resulting mechanical stress may contribute to the development or progression of keratoconus in susceptible individuals.
The experts urged parents to watch for excessive rubbing and changes in their children's vision. Timely allergy treatment and regular eye examinations can help identify potential problems early.
Other risk factors for keratoconus include:
However, not everyone who frequently rubs their eyes develops keratoconus.
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Dr Janhvi noted that keratoconus commonly begins during adolescence or early adulthood but may remain undiagnosed until vision deteriorates.
Its early symptoms can resemble common refractive errors such as myopia. Children and young adults may experience mild blurring or require frequent changes in their spectacle prescriptions, which can be mistaken for routine vision changes.
The condition can also progress gradually and initially affect only one eye, making changes harder to recognise. Routine eye examinations may not always detect early keratoconus without specialised corneal assessment, Dr. Mahipal said.
Warning signs to watch for include:
Increasing astigmatism despite repeated spectacle corrections is an important warning sign that warrants further evaluation.
Read More: Sudden Floaters, Flashes Or Blurred Vision? When Should You Seek Emergency Care For Retinal Changes
Preventing excessive eye rubbing and managing its underlying causes can help reduce avoidable stress on the cornea.
1. Break the eye-rubbing habit
2. Treat underlying allergies
If itching triggers eye rubbing, consult an ophthalmologist about appropriate treatment. Options may include topical antihistamine or mast-cell stabiliser drops, such as olopatadine or ketotifen.
Other measures include:
3. Reduce exposure to environmental triggers
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