Is Alzheimer’s Really Type 3 Diabetes? The Metabolic Story Behind Brain Energy, Menopause & Prevention

I wanted to talk about a topic that deserves far more attention than it currently gets - Alzheimer’s disease. Around 60 million people worldwide are affected, and that number is expected to keep rising. Sadly for us ladies, around two thirds of those diagnosed are women.

You may have heard in recent years, Alzheimer’s being referred to as ‘type 3 diabetes’. This idea comes from the discovery that the brain can struggle to use glucose properly long before memory symptoms ever appear. 

I’ll touch more on this as we go, but before I continue, I want to be clear that this isn’t coming from a place of fear. This isn’t about scaring anyone that they will develop Alzheimer’s, because that simply isn’t how it works. Instead, it’s actually a very empowering perspective that small, everyday changes appear to have a surprisingly strong influence over long term brain health.

So if you carry on living exactly as you are, it doesn’t automatically mean Alzheimer’s is ahead of you. But the research showing improvements with specific lifestyle shifts is strong enough that I felt called to share it in a calm and practical way.

Alzheimer’s Is a Brain Energy Problem Before It Is a Memory Problem

For decades, Alzheimer’s has been thought of mainly as a disease of memory loss. How often do we joke when we misplace our keys for the twelfth time and say, “I think I’m losing my mind”? But what we now know suggests memory decline is often the final chapter, not the beginning.

Long before anything noticeable happens, brain scans that measure how well the brain is fuelled show that memory centres start running low on energy years, sometimes decades, earlier. In other words, the brain begins struggling with fuel long before it struggles with names or navigation.

This is why Alzheimer’s is sometimes described as Type 3 diabetes. The term refers to brain insulin resistance where brain cells stop responding properly to insulin and struggle to use glucose for energy. When this happens, the cells produce less energy, come under strain, and the proteins associated with Alzheimer’s gradually begin to build up.

So rather than memory failing first, the brain often becomes metabolically underpowered long beforehand, with memory changes appearing later.

Why Women Are More Vulnerable: Oestrogen, Menopause & Metabolic Shifts

If we want to understand why Alzheimer’s is more common in women, we have to look at oestrogen. Oestrogen isn’t only a reproductive hormone, it also helps the brain manage energy. In healthy brain cells, it improves insulin sensitivity, supports glucose transport into the cell, helps energy production and keeps cell stress lower.

During perimenopause and menopause, as oestrogen naturally declines, the brain’s energy use changes too. Some research suggests brain glucose use can drop by as much as 30% during this transition. For many women this can shows up as brain fog, broken sleep, hot flushes or dips in concentration, experiences that are common, but rarely explained in biological terms.

These hormonal shifts also tend to occur alongside an increase in visceral fat. The pattern is surprisingly clear: oestrogen decreases, visceral fat increases, insulin sensitivity reduces, and brain glucose metabolism becomes less efficient. This doesn’t mean something has gone wrong, it just reflects a change in metabolic environment that may influence long term brain health over time.

The Metabolic Web: Blood Sugar, Visceral Fat & Inflammation

The brain doesn’t work in isolation from the rest of the body. When blood sugar regulation is struggling elsewhere, for example in type 2 diabetes, the brain often feels the effects too. Higher and more erratic glucose levels can place the body under stress and create ongoing low grade inflammation, which over time can influence how well the brain uses fuel.

Visceral fat and dementia are also increasingly discussed together because visceral fat (the fat stored around the organs) is particularly active in this process. As it increases, especially after menopause, the body tends to become less sensitive to insulin and slightly more inflamed, which can make the brain’s energy supply a little less efficient.

This isn’t about appearance or body shape, it’s about what’s happening internally. The reassuring part is that even modest improvements in metabolic health often bring noticeable changes in these markers sooner than people expect.

Sleep & Strength: The Most Overlooked Brain Protectors

Sleep and brain health are more closely linked than many realise. Even a single poor night’s sleep can temporarily increase certain waste proteins in the brain, which proves how important deep sleep is for overall long term health. During deeper stages of sleep, the brain clears out the by-products of the day, and when sleep becomes fragmented that clean up simply becomes less efficient.

For many people like new parents, shift workers, busy professionals, perfect sleep isn’t realistic. The goal isn’t perfection, but support in creating opportunities for better quality sleep where possible and reducing other stresses on the body so things can rebalance over time.

Movement is another powerful support, especially strength based movement. When muscles work against resistance, they release signalling molecules that travel to the brain and help support the growth and maintenance of brain cells.

Training doesn’t need to be extreme to make a difference either. Challenging your muscles a few times per week using a weight that feels demanding but manageable for around 6–10 repetitions is enough to gradually build strength.

Plus, when we regularly ask the body to do slightly difficult things, it appears to build what researchers call “cognitive reserve” which is essentially giving the brain more resilience as the years go on.

The Brain Is Adaptable

We all carry our own genetic blueprint, but Alzheimer’s isn’t determined by genes alone. Although a number of genes are linked to risk, only a small percentage of cases are directly caused by inherited mutations. For most people, everyday biology like how we live, eat, sleep and move, seems to play a much bigger role over time.

Researchers often talk about risk rather than certainty. Factors such as insulin sensitivity, inflammation, cholesterol balance and body fat distribution can all influence brain health across the years. That doesn’t mean prevention is guaranteed, but it does mean that there’s much room to support the brain long before symptoms ever appear.

In places known for longevity, such as Sardinia and Ikaria, people tend to share patterns that naturally support metabolic health like regular movement, simple meals, strong relationships and steady daily rhythms. It’s unlikely to be one special habit, but rather many small ones layering together across decades. In the next part, I’ll be going through what the research suggests can support this in everyday life, from lifestyle rhythms to nutrition.

The brain is responsive throughout life. It adapts to nourishment, rest, movement, hormonal changes and stress levels. So instead of viewing Alzheimer’s purely as a condition of memory, it can also be understood as a long term reflection of how well the brain has been supported, giving us a much more practical way to think about protecting it.