What Is Type 3 Diabetes? Insulin Resistance In The Brain That Could Trigger Alzheimer’s

Updated Dec 3, 2024 | 06:13 PM IST

SummaryDid you know type 3 diabetes, linked to insulin resistance in the brain, is associated with Alzheimer’s disease? It highlights how metabolic disorders can affect memory, cognition, and brain health.
What Is Type 3 Diabetes? Insulin Resistance In The Brain That Could Trigger Alzheimer’s

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.

What is Type 3 Diabetes?

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.

Symptoms of Type 3 Diabetes

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.

Causes of Type 3 Diabetes

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:

1. Insulin Resistance

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.

2. Type 2 Diabetes

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.

3. Environmental and Lifestyle Factors

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.

Treatments for Type 3 Diabetes

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.

Can Type 3 Diabetes Be Prevented?

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.

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28-Year-Old US Man Sees Cat’s Features On Human Faces After Brain Surgery: What Is Prosopometamorphopsia?

Updated Nov 11, 2026 | 12:00 AM IST

SummaryA 28-year-old US man developed a rare visual disorder after brain surgery, causing him to see his pet cat’s features on human faces. The condition, known as prosopometamorphopsia (PMO), affects more people than previously recognised, with some mistakenly diagnosed with psychiatric disorders.
28-Year-Old US Man Sees Cat’s Features On Human Faces After Brain Surgery: What Is Prosopometamorphopsia?

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).

How Did The Condition Begin?

Also read: Rare Canine Tooth Found In Indian Teen’s Eyelid: What Is An Ectopic Tooth?

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.

More Than 250 People Experience Facial Distortions

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.

How AI Can Help

Also read: Hours Of Sitting, Gaming And Binge-Watching OTT? Doctors Warn Of Blood Clot Risk In Young People

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.

What Is Prosopometamorphopsia?

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:

  • Droopy or stretched
  • Larger or smaller than normal
  • Displaced or out of position
  • Distorted in specific parts of the face

Two prominent subtypes are:

  • Full-face PMO: The entire face appears distorted
  • Hemi-PMO: One half of the face appears distorted

Most cases last days or weeks, although some persist for years. Around 75 case reports have so far been published.

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Eye Rubbing May Increase Keratoconus Risk: How This Everyday Habit Can Damage Your Cornea

Updated Nov 10, 2026 | 08:00 PM IST

SummaryFrequent and vigorous eye rubbing can damage the cornea and increase the risk of keratoconus, particularly in children with allergies. The condition can also progress gradually and initially affect only one eye, making changes harder to recognise.
Eye Rubbing May Increase Keratoconus Risk: How This Everyday Habit Can Damage Your Cornea

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.

Why Should You Avoid Rubbing Your Eyes?

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:

  • Contribute to corneal thinning and biomechanical weakening.
  • Accelerate keratoconus in susceptible individuals.
  • Cause corneal abrasions and increase the risk of infection.

Also read: Ozempic, Zepbound: US FDA Orders New Warning Over Rare Eye Risk

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.

Why Are Children More At Risk?

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:

  • Vernal keratoconjunctivitis (VKC)
  • Atopic eye disease
  • Family history of keratoconus
  • Genetic predisposition
  • Certain connective tissue disorders

However, not everyone who frequently rubs their eyes develops keratoconus.

Read More: 6 Million People In Delhi Living With Poor Vision: AIIMS Study

Why Is Keratoconus Often Diagnosed Late?

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 myopia
  • Progressive or irregular astigmatism
  • Frequent changes in spectacle prescriptions
  • Reduced visual clarity despite corrective lenses
  • Ghosting, glare or double vision in one eye
  • Difficulty driving at night

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

How Can You Prevent Corneal Damage?

Preventing excessive eye rubbing and managing its underlying causes can help reduce avoidable stress on the cornea.

1. Break the eye-rubbing habit

  • Avoid pressing or massaging closed eyelids.
  • Use a cold compress when your eyes itch.
  • Avoid rubbing your eyes even through a towel or handkerchief.
  • Keep children's fingernails short to minimise accidental injury.

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:

  • Using preservative-free artificial tears for irritation
  • Treating associated blepharitis or dry eye
  • Avoiding prolonged use of topical steroid drops without medical supervision

3. Reduce exposure to environmental triggers

  • Avoid dust, smoke and known allergens
  • Wear protective glasses outdoors
  • Avoid direct airflow from air conditioners.

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The Weekend Sleep Catch-Up: Can Two Days of Extra Sleep Undo Five Days of Sleep Deprivation?

Updated Nov 10, 2026 | 02:00 PM IST

SummarySleeping longer over the weekend can certainly help you feel less tired, but it cannot completely compensate for a week of inadequate sleep.
The Weekend Sleep Catch-Up: Can Two Days of Extra Sleep Undo Five Days of Sleep Deprivation?

Credit: iStock

Come Saturday morning, many people have just one thing on their mind: catching up on sleep. After a week of early mornings, office deadlines, late-night screen time and household responsibilities, the weekend feels like the perfect opportunity to stay in bed for a few extra hours. Some people even sleep until noon, believing that the extra rest will make up for all those late nights. But is it really possible to undo five days of poor sleep in just two days?

Unfortunately, the brain doesn't work that way. Sleeping longer over the weekend can certainly help you feel less tired, but it cannot completely compensate for a week of inadequate sleep.

Sleep is much more than physical rest. It is when the brain gets down to some of its most important work. Memories are processed, information gathered during the day is organised, and the brain gets an opportunity to recover from constant activity. When we repeatedly cut short our sleep, these processes can suffer.

Why Do We Feel Better After Sleeping In?

Think about how you feel after several nights of going to bed late. You may find yourself forgetting small things, struggling to concentrate during meetings or becoming unusually irritable over minor issues. These are some of the ways sleep deprivation can affect everyday functioning.

Sleeping for a few extra hours over the weekend can ease some of this fatigue. You may feel more alert and find it easier to concentrate. However, feeling refreshed is not necessarily the same as being fully recovered. Certain effects of repeated sleep restriction, particularly on attention and reaction time, can take longer to resolve.

Can Weekend Lie-ins Disturb Your Sleep Cycle?

There is another side to this weekend habit that people rarely consider. If you sleep at 11 pm during the week but stay awake until 2 or 3 am on Friday and Saturday, your body's internal clock can get disrupted.

This internal timing system, called the circadian rhythm, helps regulate when you feel sleepy and when you wake up. Large changes in sleep timings can make it harder to fall asleep on Sunday night. Before you know it, Monday morning arrives and you are back to feeling exhausted.

It becomes a familiar cycle: insufficient sleep during the week, prolonged sleep on weekends and difficulty getting back into a routine.

What Does Repeated Sleep Deprivation Do To The Brain?

One of the biggest areas affected is memory. Sleep plays an important role in consolidating information, which is why a poor night's sleep can make it harder to remember things or absorb new information the following day.

It can also affect emotional regulation. People who regularly sleep less may become more impatient, anxious or sensitive to everyday stress. Their ability to focus and make decisions may also take a hit.

Persistent sleep deprivation has also been associated with metabolic and cardiovascular problems. It is therefore important not to treat poor sleep as an unavoidable part of a demanding work schedule.

What Is A Healthier Way To Catch Up On Sleep?

Rather than depending on Saturday and Sunday to recover, try making small changes to your routine throughout the week.

  • Keep a consistent schedule: Try to go to bed and wake up at roughly the same time every day.
  • Don't compromise on sleep duration: Most adults need around seven to nine hours of sleep each night.
  • Put your phone away before bedtime: Late-night scrolling can keep the mind stimulated and delay sleep.
  • Be mindful of caffeine: That evening cup of coffee may be affecting your ability to fall asleep.
  • Step outdoors in the morning: Natural daylight helps regulate the body's sleep-wake cycle.
  • Pay attention to persistent tiredness: If you wake up exhausted despite getting enough sleep, speak to a doctor. Sleep disorders such as obstructive sleep apnoea may need to be ruled out.
A weekend lie-in once in a while is perfectly understandable, especially after a particularly demanding week. But making it your regular strategy for dealing with sleep deprivation is not ideal.

Your brain needs rest every day, not just when the calendar says it is the weekend. Instead of treating sleep as something you can postpone and recover later, make it a non-negotiable part of your daily routine.

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