Alzheimer’s disease is shaped by many factors, but nutrition is one area where individuals can take meaningful steps to support long-term brain health. Dietary patterns that emphasise whole foods and reduce refined carbohydrates are increasingly recognised as part of a pattern associated with lower dementia risk. They are not cures, but they may form part of a broader strategy to protect metabolic and brain health.

The brain depends heavily on glucose for energy, yet its ability to take up and use glucose becomes impaired in Alzheimer’s disease (1). This has led  researchers to explore whether ketones, produced when carbohydrate intake is restricted, could  provide an alternative energy source (2). 

Some researchers describe Alzheimer’s as “type 3 diabetes” to highlight evidence of brain insulin resistance and impaired insulin signalling in affected regions (3). While this label is not an official diagnosis, it does capture observations that many people with Alzheimer’s show reduced cerebral glucose metabolism and altered insulin pathways, even in the absence of systemic diabetes (4). Dietary approaches that reduce refined carbohydrates and prioritise nutrient-dense foods may improve blood-glucose regulation, insulin sensitivity and vascular health. These factors matter because the brain is not isolated from the rest of the body. The health of the blood vessels, the regulation of glucose and the presence of chronic metabolic dysfunction can all influence cognitive health 

A meta-analysis published in Journal of Nutrition, Health & Aging in 2024 reviewed randomised controlled trials of ketogenic diets in Alzheimer’s patients (5). It found modest short‑term improvements in cognitive test scores, though the authors cautioned about small increases in lipid levels and emphasised the need for medical oversight. A large long‑term study published in Alzheimer’s & Dementia in 2026 followed more than 130,000 participants in the Nurses’ Health Study and Health Professionals Follow‑Up Study (6). Researchers examined adherence to the Mediterranean diet and the Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND) diet. Both patterns emphasise whole foods such as vegetables, fruits, nuts, legumes, fish and olive oil, while limiting refined carbohydrates and processed foods. Participants with the highest adherence had a 21 percent lower risk of dementia with the Mediterranean diet and a 14 percent lower risk with the MIND diet compared with those with the lowest adherence. These diets were also linked to slower cognitive ageing and reduced risk of subjective cognitive decline, highlighting the protective role of nutrient‑dense, lower‑carbohydrate whole‑food eating in brain health. 

September 2026 marks the 15th anniversary of World Alzheimer’s Month, under the theme “The Earlier You Know, The More You Can Do: A Dementia Diagnosis Matters.” Early detection and access to care remain essential, and nutrition is one tool among many that may help lower risk and support resilience. By reducing stigma and encouraging timely diagnosis, patients and families can benefit from medical care, lifestyle strategies, and community support sooner. Choosing whole foods and reducing reliance on refined carbohydrates is one method people can use today to support long‑term brain health.

No single food or dietary pattern can guarantee protection from dementia. But what happens in the brain is not separate from what happens in the rest of the body. Choosing whole foods, reducing refined carbohydrates and improving metabolic health are practical steps that may help support the brain over the longer term. 

References

1. Xiao, X., Yan, X., Liang, C., & Yang, Y. (2026). Metabolic dysfunction and mitochondrial failure in Alzheimer’s disease: integrating pathophysiology, clinical evidence and emerging interventions. Frontiers in neurology, 17, 1772036. https://doi.org/10.3389/fneur.2026.1772036
2. Salgueiro, A. M., Ferreira-Marques, M., Ribeiro, R. F. N., Lopes, S. M., Pereira, D., Costa, D. G., Santana, M. M., Pereira de Almeida, L., & Cavadas, C. (2026). Ketogenic diet as a therapeutic strategy for neurodegenerative diseases: From mechanisms to translational challenges. Translational Neurodegeneration, 15, Article 24. https://link.springer.com/article/10.1186/s40035-026-00557-1
3. Verma, A., Sharma, M., Alam, O., & Anwer, T. (2026). Type 3 diabetes: A molecular link between cerebral insulin resistance and neurodegeneration via AGE–RAGE signaling. European Journal of Neuroscience, 63(1), e70364.https://doi.org/10.1111/ejn.70364
4. Pliszka, M., & Szablewski, L. (2026). Insulin Signaling in Alzheimer’s Disease: Association with Brain Insulin Resistance. International journal of molecular sciences, 27(3), 1222. https://doi.org/10.3390/ijms27031222
5. Rong, L., Peng, Y., Shen, Q., Chen, K., Fang, B., & Li, W. (2024). Effects of ketogenic diet on cognitive function of patients with Alzheimer’s disease: A systematic review and meta-analysis. The Journal of Nutrition, Health & Aging. https://holdsup.app/paper/38943982 
6. Morris, M. C., Tangney, C. C., Wang, Y., Sacks, F. M., Bennett, D. A., & Aggarwal, N. T. (2015). MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia, 11(9), 1007–1014. https://doi.org/10.1016/j.jalz.2014.11.009 
7. Mózes, N., Fehér, Á., Csípő, T., Fazekas-Pongor, V., Lipécz, Á., Major, D., Lehoczki, A., Dósa, N., Pártos, K., Csík, B., Yi, H. W., Kaposvári, C., Horváth, K., & Fekete, M. (2026). Ketogenic Diet and Brain Health: Cerebrovascular Mechanisms, Neuroprotection, and Translational Implications. Nutrients, 18(7), 1091. https://doi.org/10.3390/nu18071091