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.
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Worldwide, more than 57 million people live with dementia, experiencing symptoms such as short-term memory loss, difficulty finding words, confusion about time or place, trouble with complex tasks, and changes in mood or personality. Around 10 million new cases are diagnosed every year.
Recent studies suggest that the average lifetime risk of developing dementia after age 55 is about 42%.
A new study has found that maintaining healthy blood pressure, controlling blood sugar, and avoiding smoking during middle age could significantly reduce the risk of developing dementia.
People who maintained these three health measures between the ages of 48 and 68 lived, on average, nearly 13 additional years without dementia, according to the study published in the journal Neurology Open Access.
"Our findings argue that people need to actively avert these factors in midlife as a strategy for preserving brain health for more than a decade," said study senior investigator Josef Coresh, Professor in the Department of Population Health at NYU Langone.
"Discovering new ways to delay dementia is crucial with 42% of Americans at risk for developing the condition at any time after age 55," he added.
Researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing community-based study that began in 1986. It has tracked participants for decades, measuring midlife vascular risk factors and the development of dementia.
The analysis included 12,409 adults with an average age of 56, all of whom were free of dementia at the start of the study. Researchers assessed three key risk factors:
Researchers also examined how midlife cardiovascular risk factors affected dementia-free survival across different demographic groups.
Among participants with all three risk factors:
"Hopefully, these results will encourage people to stop smoking and watch their vascular health closely from age 48 on."
Dementia is an umbrella term for a significant decline in mental function that interferes with daily life. It commonly affects memory, thinking, and reasoning abilities and is caused by underlying conditions such as Alzheimer's disease or vascular dementia.
While there is currently no cure, the WHO says up to 45 per cent of dementia risk can be prevented or delayed by addressing modifiable risk factors such as tobacco and alcohol use, physical inactivity, social isolation, air pollution, and noncommunicable diseases (NCDs), including high blood pressure and diabetes.
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Through the first quarter of the twenty-first century, it has been clear that the global menace of infectious diseases has become very different in terms of their causal factors and predictability.
A 2022 review in Nature Reviews Microbiology by Princeton professors Rachel Baker and Jessica Metcalf aptly pointed out how climate change, urbanization, and wider travel and trade determine when, where, and how outbreaks of infections happen. Examples of such outbreaks are numerous globally, viz. SARS, H1N1, MERS, Ebola, Zika, and COVID-19 outbreaks. It has also been realized by biomedical scientists that more than half of all known pathogenic diseases have at some point been worsened by climate-change-related events.
As a result, research on climate-disease links has surged since the recent pandemic.
Evidence supporting this climate-disease relationship is also abundant in the Indian context. A major example is our experience with dengue infections, which are clearly losing their seasonal predictability. Contrary to its usual temporal link with the monsoon, India has encountered an unusually early transmission in 2026, with nearly 7,000 cases reported by end-February, as per the National Center for Vector-Borne Diseases Control data. The vector has also expanded its geographical distribution, for example into Himalayan towns such as Darjeeling over the past decade.
Meanwhile, the Integrated Disease Surveillance Program in India also reports bimodal waves of influenza transmission and infections with respiratory syncytial virus (RSV) surge during the monsoon. These provide evidence that overlapping and compressed disease seasons are becoming more common.
Warming temperatures and erratic rainfall alter mosquito breeding cycles and pathogen incubation periods, while floods can create sudden transmission spikes in a population. On the other hand, rapid urbanization increases overlap among human, animal, and vector habitats. India is expected to have an urban population of close to 600 million by 2031. This will further intensify livestock density, land-use change, and human-wildlife contact, raising the risk of zoonotic spillovers.
As is evident globally now, global travel and trade will carry the pathogens across borders way faster than health systems can respond. Thus, reactive outbreak responses, of testing, isolating, and reporting only after cases show a surge, are strategically too slow. However, genomic and wastewater surveillance offer scalable alternatives. For example, such efforts in India could detect SARS-CoV-2 variants in sewage much before case counts rose in a population.
Similar experience has been gathered in cities like Bengaluru, wherein wastewater monitoring could track influenza and RSV circulation independent of individual testing. Artificial intelligence and machine learning models further add to the forecasting capacity. Modelling climate, land-use, and animal-movement data can flag likely zoonotic spillover risks well before an outbreak begins.
India's national zoonotic disease prioritization exercise and state-level One Health pilot studies in Gujarat and Rajasthan show that human, veterinary, and environmental data must be integrated. Such interdisciplinary cohort research, tracking populations across seasons and geolocations, can achieve usable forecasts integrating discrete data. Thus, building such predictive, One Health-oriented research and surveillance infrastructure will be imperative for India to achieve optimal pandemic preparedness.
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It has been long suspected that Western diets could contribute to the risk of colorectal cancer. The theory may finally have a clearer scientific explanation.
A new study suggests that gut bacteria can convert compounds produced by high-fat, low-fibre diets into cancer-causing chemicals. The research sheds light on how unhealthy eating habits may lead to cancerous tumour growth in colon in the long term.
Published in the journal Gut, the research was led by Dr. Annika Osswald (first author) and Dr. Soeren Ocvirk (corresponding author), along with a large team of international scientists.
The collaboration included researchers from Technical University of Munich (TUM), Germany, German Institute of Human Nutrition (DIfE), RWTH Aachen University, Freie Universität Berlin, University Hospital of Regensburg, and other institutions.
Researchers found that a western-style diet, which is commonly high in red and processed meat, saturated fats, refined carbohydrates and ultra-processed foods, significantly changes the composition of the gut microbiome.
These altered bacteria then modify bile acids in ways that promote inflammation and create an environment that accommodates the development of colorectal cancer tumours.
According to the researchers, diet alone is not the only factor. The trillions of microbes living in the intestine determine how food is processed, producing metabolites that can either protect the gut or damage it.
The study found that specific bacterial groups transformed bile acids into compounds that stimulated tumour growth in the colon.
This provides one of the strongestt explanations yet for why western dietary patterns have consistently been associated with higher risk of colorectal cancer.
"Our findings highlight the critical interaction between diet, gut microbes and cancer biology," the researchers noted, adding that targeting the microbiome could become a future strategy for preventing colorectal cancer.
Also read: Why English Actor Peter Duncan Is Advocating For Focal Therapy After His Prostate Cancer Treatment?
A western diet typically includes:
Previous research has repeatedly linked this eating pattern with obesity, diabetes, heart disease and colorectal cancer, but scientists have long found it challenging to explain the exact cause until now.
The human gut is home to trillions of bacteria that help digest food, regulate immunity and produce beneficial compounds like fatty acids.
A fibre-rich diet supports good bacteria that reduce inflammation, whereas diets high in fat and processed foods can cause microbial imbalance.
The new findings suggest this imbalance changes how bile acids are metabolised, increasing the production of molecules capable of damaging the colon and supporting cancer growth in the long run.
Also read: WHO Cancer Agency Flags 3 Common Medicines As Carcinogenic: What It Means For Millions Of Patients
Earlier research has linked harmful gut bacteria, including toxin-producing E. coli, with DNA damage that may begin early in life and contribute to the rise of colorectal cancer among younger people.
However, the latest findings do not prove diet alone causes cancer. Genetics, obesity, physical inactivity, sedentary life, smoking and alcohol consumption also influence risk.
However, they say maintaining a fibre-rich diet with fruits, vegetables, legumes and whole grains may help preserve a healthier gut microbiome and lower long-term colorectal cancer risk.
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