Understanding the role of insulin and how it can impact your brain health

Many of us know insulin for its vital role in helping to regulate blood sugar levels throughout the body. As one of our key hormones, insulin helps to produce and facilitate the uptake of glucose – our body’s main source of energy. This glucose is then moved into our cells where it is metabolised to fuel the essential biological functions that we need to stay alive. But, while insulin is more so recognised for its metabolic benefits, its influence also extends to our brain health, as it is key in powering various processes and helping us to carry out everyday cognitive functions. 

The brain, despite making up only 2% of our total body weight, consumes roughly 20% of the body’s energy, and it uses this energy to support critical brain function such as neuroplasticity and the creation of memories. Insulin contributes to creating this energy by regulating glucose transport across the blood-brain barrier, further facilitating its absorption by the brain’s neurons. In addition to energy regulation, insulin also influences essential elements (like neurotransmitter function) for helping to protect and nurture our brain health. 

Maintaining stable insulin levels helps to protect the brain’s cognitive ability to think, learn and remember. When insulin regulation falters, it can disrupt the energy supply to the brain cells, impairing communication between neurons and increasing the risk of cognitive decline and neurodegenerative diseases such as dementia and Alzheimer’s disease.

Emerging research now highlights the impact of insulin resistance, not just in the body but also within the brain. Insulin resistance happens when cells don’t respond well to the insulin released and, while this can be due to numerous medical conditions such as type 1 diabetes, it is also linked to a combination of a sedentary lifestyle and excess body fat (specifically visceral fat found around the abdomen). 

Most recently, insulin resistance has been named as a contributing factor to cognitive decline and neurodegenerative diseases such as dementia and Alzheimer’s disease. When insulin signalling is impaired, glucose metabolism in brain cells becomes inefficient leading to cellular stress, inflammation and eventually neuron dysfunction. This connection is sometimes referred to as ‘type 3 diabetes’, indicating the significant role that insulin resistance can have on brain health.

How does insulin resistance actually impact brain health?

Poor insulin regulation can lead to chronic high blood sugar levels, commonly observed in type 2 diabetes. These elevated levels have the ability to damage both the blood vessels and nerves found in the brain, as well as increasing the risk of a stroke and dementia. It can also lead to other forms of cognitive impairment, such as a reduced memory and a slower processing speed. Furthermore, insulin resistance promotes inflammation and oxidative stress which contribute significantly to brain ageing and hinder the brain’s ability to repair itself. 

How can we keep insulin resistance at bay?

One of the key ways to ensure insulin resistance doesn’t impact your brain health is to adopt a healthy diet, one of Brain Health Network’s six core pillars. 

Diet plays a key role in supporting insulin sensitivity while maintaining stable blood sugar levels. Ensuring that you consume foods that release glucose slowly into the bloodstream to prevent excessive spikes and crashes is the best way to do this – a diet rich in nutrient-dense, low glycaemic index foods that supports both metabolic and brain health by reducing inflammation and oxidative stress.

Our top 5 foods for helping to maintain blood sugar levels while supporting your brain health 

1. Leafy green vegetables
   Vegetables such as spinach, kale and broccoli are low in carbohydrates and high in antioxidants, vitamins and minerals. They promote insulin sensitivity and provide neuroprotective benefits by reducing inflammation and oxidative damage.
   
2. Fatty fish
   Rich in omega-3 fatty acids (particularly DHA), fatty fish like salmon, mackerel and sardines support the integrity of our brain cells while reducing insulin resistance. Omega-3s are also critical for cognitive processes including memory and learning.
   
3. Nuts and seeds
   Almonds, walnuts, flaxseeds and chia seeds are packed with healthy fats, fibre and protein, all of which help moderate blood sugar levels. They also provide vitamin E and other antioxidants which are important for protecting brain cells from oxidative stress.
   
4. Whole grains
   Foods such as oats, quinoa and brown rice have a low glycaemic index and release glucose gradually, avoiding blood sugar spikes. These whole grains also contain B vitamins which provide essential energy for the brain enabling us to maintain cognitive function.
   
5. Berries
   Blueberries, strawberries and blackberries are rich in flavonoids and antioxidants that improve insulin sensitivity while working to reduce neuroinflammation. They have been shown to enhance memory and help keep cognitive decline at bay.
   

It’s important to remember that insulin is much more than another hormone simply helping to regulate our blood sugar levels. Rather, it is a key player in sustaining our brain health and cognitive function. 

Maintaining insulin sensitivity through a healthy, balanced diet is essential in supporting our brain’s energy supply, reducing inflammation and helping to protect against cognitive decline in later life. Emphasising nutrient-rich foods like leafy greens, fatty fish, nuts, whole grains, and berries can help promote a stable blood sugar balance while contributing positively to long-term brain health. In addition to diet, the risk of insulin resistance can be reduced by maintaining a healthy weight, engaging in regular physical activity (exercise and active lifestyle), managing stress and getting enough sleep.  You can find further details about these approaches on our website.

Adopting these dietary habits reflects a forward-thinking approach to cognitive wellbeing, prioritising prevention and a sustained mental sharpness throughout life.