Advice from a neuroscientist on how to reduce the risk of Alzheimer’s disease – think S.H.I.E.L.D

Alzheimer’s disease is one of the most challenging neurodegenerative conditions that we face today. At the end of 2025 alone, approximately 550,000 people were diagnosed with the condition, and this figure is expected to rise to 1 million by 2030.

What so many of us are unaware of, is that Alzheimer’s disease actually begins 20 years, sometimes even more, before memory loss and other symptoms develop.

While there is no current cure or way to definitively prevent Alzheimer’s disease, what is within our power, is our ability to help reduce the risk of neurodegenerative diseases, starting in our earlier years – from the age of 30 when the hippocampus, responsible for our learning, memory and executive function starts to decline.

The SHIELD mnemonic is a great way of ensuring that you’re looking after your brain health. SHIELD stands for sleep, handling of stress, interaction with friends, exercise, learning and diet.

At Brain Health Network, these translate into our 6 core pillars: sleep, healthy life, exercise, active mind, nutrition and gut health, all of which come together to help build cognitive reserve and resilience as we enter our later years.

Breaking these down, here are more detailed descriptions on what you can do daily, to look after your brain health.

SLEEP is key for brain health and ultimately, total body health. When you have a bad night’s sleep have you ever felt exhausted, dehydrated and easily irritable? This is due to a lack of sleep, for this is the time our brains need to reset.

Toxic waste including beta-amyloid and other proteins that accumulate throughout the day, are during this time eliminated through the glymphatic system, while our memories are consolidated as the brain processes, sorts and stores this new information. In addition, the formation of new neural pathways and cellular repair also begin to take place.

The absence of good sleep is highly inflammatory to the brain and results in the over secretion of cortisol, a stress hormone. Inflammation in the brain is a clear risk factor for Alzheimer’s disease. So, it’s easy to see why inadequate or fragmented sleep are notably linked to the progression of Alzheimer’s disease, and why the quality of sleep forms the foundation for a reduced risk of cognitive decline in later life.

HANDLING STRESS the right way plays a huge role in managing the risk of neurodegeneration (progressive irreversible damage to nerve cells), in the hippocampus and prefrontal cortex, both of which work closely together in memory and learning. Elevated stress levels, which are prevalent for so many of us in today’s fast paced world, can cause widespread inflammation (an immune response) in our bodily systems. This whole body response triggers inflammation in the cells of the brain (neuroinflammation) as inflammatory cytokines breach the blood brain barrier. These inflammatory secretions badly affect the support and repair cells of the brain – for example astrocytes and microglia which usually help to temper neurodegeneration. They go ‘rouge’ and instead of helping to repair damaged cells, they exacerbate neuronal damage, driving neurodegeneration and the development of cognitive decline, dementia and Alzheimer’s disease.

As Phil Haydon, Professor of Neuroscience Ph.D Emeritus, further explains, ‘when the brain is exposed to repeated stress or in a similar manner, sleep is interrupted or insufficient, the protective processes serving our brain health are suddenly compromised. Sleep is when the brain is cleared of toxic waste through the glymphatic system, while memories and the day’s events are consolidated. That’s why sleep and reducing stress is so important – as over time sustained imbalance and chronic neuroinflammation can interfere with neuroplasticity which is needed to help maintain brain health in later life.’

It’s inevitable that we will all experience stress, but the importance of integrating stress regulating techniques can have a wide benefit to both brain health and body. In turn, this can reduce the risk of chronic diseases and systemic inflammation helping to increase cognitive reserve and longevity.

INTERACTION WITH FRIENDS also falls under our pillar of Active Mind, where we detail in depth the importance of human connection and social interaction. As Professor James Goodwin identifies, ‘social isolation is one of the biggest risk factors for cognitive decline and dementia’.

Social interaction stimulates complex cognitive processes including memory, language and planning as well as emotional wellbeing. Each of these encourage mental stimulation and the process of neuroplasticity – the development of new neural pathways in the brain.This adaptability then enables the brain to compensate for future damage while maintaining cognitive function.

EXERCISE consistently comes up in helping to reduce the risk of cognitive decline in later life. Daily aerobic exercise and resistance training work to improve cerebral blood flow to the brain, therefore increasing the levels of oxygen delivered to the brain. This helps to reduce any inflammation in the brain and body, while promoting neurotrophic factors (essential proteins that support neuron survival) to support synaptic plasticity. Exercise has long been associated with helping to keep the risk of cognitive decline as low as possible.

LEARNING NEW THINGS, like staying socially active, falls under our Active Mind pillar. This is because both are working to quite literally keep the mind active, through skill acquisition and intellectually demanding activities. High levels of cognitive activity show a greater capacity to compensate for neurological changes as we get older, building cognitive reserve. With this cognitive reserve we then have more cognitive resilience in later life against age-related decline.

DIET is always of high importance, but even more so when it comes to brain health. The Mediterranean diet in particular, is notably known for being associated with reducing the risk of cognitive decline. Rich in vegetables, whole grains, fruits, nuts and healthy fats, studies have even suggested a reduced risk of dementia, potentially up to 23%, partly by improving vascular health. This is due to the high level of antioxidants, omega-3 fatty acids and micronutrients which work together to combat oxidative stress and support synaptic plasticity.

In addition to the Mediterranean diet, are the DASH diets and MIND diets, both of which follow the same healthy eating patterns of the Mediterranean, while eliminating processed red meat, butter, cheese and sweets.

By remembering the SHIELD mnemonic, and leveraging these modifiable lifestyle factors, there is a clear pathway to reducing the risk of cognitive decline. It’s important to remember however, that there is no one way of completely eliminating risk. The cumulative effect of having a healthy diet, adequate sleep, daily movement and social interaction do pave the way for cognitive longevity and vitality in later life.

Master the Brain Health Method

The SHIELD mnemonic is a powerful starting point, but protecting your brain requires a structured, lifelong approach. At Brain Health Network, we’ve refined these principles into The Brain Health Method: The Power of Six.

Discover how these six lifestyle factors work synergistically to build a resilient brain and reduce your risk of cognitive decline.

Read: The Power of Six Strategy →