Neurodegeneration: Ageing, Brain Health and What We Can Influence

with populations ageing across the UK and globally, neurodegenerative diseases are no longer niche conditions, but a central public health challenge. alzheimer's disease, parkinson's disease and related dementias are increasingly common, not only because people are living longer, but because modern lifestyles are interacting with biological ageing in ways we are only beginning to understand.

prevalence and why it matters

in the UK, around 900,000 people are living with dementia, a number projected to exceed 1.5 million by 2040 (Alzheimer's Society, 2024). alzheimer's disease accounts for approximately 60–70% of cases, while vascular dementia and mixed forms make up much of the remainder. parkinson's disease affects an estimated 145,000 people in the UK, with incidence rising sharply with age (Parkinson's UK, 2023). although traditionally viewed as a movement disorder, parkinson's is now understood as a multisystem condition, often involving cognitive, metabolic and gastrointestinal changes years before diagnosis.

these figures highlight that neurodegeneration is not an isolated late-life event, but the result of processes that unfold over decades.

what drives neurodegeneration: beyond ageing

age is the strongest risk factor, but it is not sufficient to explain disease. current models describe neurodegeneration as the outcome of interacting biological processes, including protein misfolding, chronic inflammation, mitochondrial dysfunction and impaired cellular repair. large systematic analyses suggest that modifiable risk factors account for up to 40% of dementia cases globally (Livingston et al., 2020). these include cardiovascular health, metabolic dysfunction, physical inactivity, social isolation and education level.

in parkinson's disease, emerging evidence indicates that pathology may begin outside the brain — particularly in the gut and peripheral nervous system — before progressing centrally. this has shifted research attention towards early-life and mid-life exposures.

the gut-brain axis: a common thread

one of the most compelling developments across both parkinson's and alzheimer's research is the role of the gut–brain axis. in parkinson's disease, gastrointestinal symptoms such as constipation often appear years before motor symptoms. human studies show that individuals with parkinson's exhibit altered gut microbiota composition, including reduced levels of short-chain fatty acid–producing bacteria (Romano et al., 2021).

similar patterns are emerging in alzheimer's disease. systematic reviews indicate that microbiome changes are associated with neuroinflammation and amyloid deposits — key features of disease pathology (Xu Lou et al., 2023). these findings support a model where gut-derived signals influence brain ageing through immune and metabolic pathways.

nutrition and brain health

nutrition is one of the most consistent modifiable factors linked to neurodegenerative risk. prospective cohort studies and meta-analyses show that adherence to mediterranean-style dietary patterns is associated with a reduced risk of cognitive decline and alzheimer's disease (Nucci et al., 2024). similar benefits are observed with the MIND diet.

mechanistically, these diets appear to support brain health through anti-inflammatory effects, improved vascular function and oxidative stress reduction. importantly, they also promote a diverse gut microbiome — reinforcing the link between diet and the gut–brain axis.

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specific nutrients have also been studied. systematic reviews suggest that omega-3 fatty acids, polyphenols (plant antioxidants) and certain vitamins (including B vitamins and vitamin D) may support cognitive function, although stronger and more consistent effects are observed for whole dietary patterns rather than isolated nutrients.

in parkinson's disease, emerging research suggests that dietary fibre and fermented foods may influence symptom progression via microbiome-mediated pathways. these findings align closely with traditional dietary approaches such as those reflected in Grounded Kitchen, where plant diversity, fermentation and balanced meals naturally support both metabolic and microbial health.

prevention, delay and realistic expectations

it is important to be precise: nutrition and lifestyle do not "prevent" neurodegenerative disease in absolute terms. however, evidence strongly supports their role in delaying onset, reducing risk and influencing progression. even modest delays in disease onset at a population level translate into substantial reductions in overall prevalence and healthcare burden.

the broader message is that brain health is cumulative. the same systems that regulate cardiovascular, metabolic and gut health also shape neurodegeneration risk. this reframes prevention not as a late intervention, but as a lifelong process.

from awareness to application

understanding neurodegeneration requires moving beyond simplified narratives. these are not purely genetic or inevitable conditions, but complex outcomes shaped by biology, environment and behaviour over time. the growing evidence around nutrition and gut health offers a practical entry point — not as a cure, but as a meaningful lever within a broader system. Grounded Kitchen's approach reflects this philosophy: supporting long-term health through dietary patterns that align with how the body, and brain, actually function.

Written by: Gabi Zaromskyte, MSc, ANutrRegistered Nutritionist | Intuitive Eating Counsellor | Holistic Health Coach