Alzheimer’s disease mainly affects older adults. As the average age of many global populations grows, scientists expect case numbers to rise.
It’s the most common form of dementia, accounting for around 60–80% of dementia cases.
In brief, Alzheimer’s is caused by damage to nerve cells, or neurons, in the brain.
Experts believe that this damage stems from a buildup of particular proteins within and between neurons. With time, the level of damage increases.
Early symptoms include memory problems, apathy, and depression.
As the disease progresses, the effects on thinking skills become increasingly pronounced. Eventually, it's very difficult or impossible to do daily tasks.
Current treatments can help slow the progression, but there’s no cure.
Some scientists are designing better treatments, others are exploring the risk factors, and still others are looking at whether our diets play a role.
In this article, we’ll investigate links between nutrition and Alzheimer’s risk.
A cautionary note
Before jumping in, we need to clarify that scientists are still fleshing out the links between nutrients, dietary patterns, and dementia.
There’s no set-in-stone, evidence-based anti-Alzheimer’s diet. We’re not there yet.
But as it stands, the evidence suggests that a healthy diet might reduce your risk of developing dementia later in life.
Still, scientists have much more work to do. In particular, we need longer and larger studies.
Plus, everyone’s different, so a dietary pattern that protects one person might not be as effective for someone else.
Alzheimer’s and nutrition
A recent review of 38 studies, published in 2023, investigated links between Alzheimer’s and nutrition.
In general, the authors concluded that following a Western diet is a risk factor for developing this form of dementia.
Let’s look at some of the specifics they covered.
Carbs and blood sugar
High-glycemic index foods cause your blood sugar levels to rise quickly. This is because they contain carbs that our bodies digest fast. Baguettes, potatoes, and white bread are examples of these foods, and soda also ranks high on the glycemic index.
These foods and drinks seem to cause more protein buildups in people with a gene called APOE-e4.
Having one copy of this gene increases your risk of developing Alzheimer’s, and having two copies increases it further.
Interestingly, this gene variant is also linked to an increased risk of developing insulin resistance — the forerunner to type 2 diabetes.
In the U.S., around 20–30% of people have one or two copies of APOE-e4.
The Western diet
The review’s authors observe that the Western diet increases Alzheimer’s risk.
And some studies show that consuming more ultra-processed foods is associated with a higher risk of dementia.
This research also found that substituting unprocessed or minimally processed foods for ultra-processed foods was associated with a lower risk of dementia.
If you’d like to learn more, ZOE has an article on the links between ultra-processed food and brain health as you age.
A number of studies have investigated whether omega-3 essential fatty acids might reduce the risk of developing Alzheimer’s disease.
The three main types of omega-3s are alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA).
ALA comes from plants, and DHA and EPA are mostly found in fatty fish.
Join our mailing list
Sign up for fresh insights into our scientific discoveries and the latest nutrition updates. No spam, just science.
The authors of the 2023 review write: “Adequate levels of omega-3 polyunsaturated fatty acids, especially EPA and DHA, are associated with slower rates of cognitive decline and reduced risk of [Alzheimer’s disease].” This is born out by other research.
Meanwhile, some scientists are also investigating whether omega-3 supplements might help reduce symptoms in people with early stage Alzheimer’s. So far, though, the evidence is mixed.
Another review, published in 2019, took a slightly different approach. The authors focused on specific dietary patterns and Alzheimer’s risk. They reviewed 26 studies.
In agreement with the review we just covered, the authors concluded that “Adherence to [a] healthy diet” seems to decrease the risk of Alzheimer’s disease.
Let’s look at some of the dietary patterns they examined.
The Mediterranean diet
The Mediterranean diet generally contains plenty of vegetables, legumes, whole grains, nuts, olives, and olive oil.
It also includes moderate amounts of fish and fat-free and low-fat dairy products, as well as small amounts of red and processed meats.
The authors of the review conclude that following the Mediterranean diet more closely seems to be linked to a reduced risk of Alzheimer’s.
Some research suggests that those who stick most closely to the Mediterranean diet have a 20% reduced risk of developing Alzheimer’s, compared with those who follow it least closely.
The DASH diet
The Dietary Approaches to Stop Hypertension (DASH) diet is low in saturated fats, overall fat, and red and processed meats. It’s rich in fruits, vegetables, whole grains, and low-fat dairy.
Designed more than 20 years ago, the DASH diet effectively reduces high blood pressure.
The DASH diet might also reduce the risk of cognitive decline and Alzheimer’s.
Again, the review's authors suggest that this is because it reduces inflammation and oxidative stress.
The MIND diet
Thankfully, the Mediterranean-DASH Intervention for Neurodegenerative Delay Diet is tidily abbreviated to the MIND diet.
As the name implies, this dietary pattern has elements of the Mediterranean and DASH diets.
In particular, it focuses on plant foods linked to dementia prevention, including:
leafy green vegetables
one glass of wine a day
The MIND diet also contains small amounts of fish and poultry but limits the intake of red meat, sweets, pastries, cheeses, fried food, butter, and margarine.
Again, the review concludes that this diet might reduce your risk of developing Alzheimer’s.
The link may stem from a reduction of inflammation and oxidative stress and an increased intake of omega-3s, the authors suggest.
What to make of it all
Because there’s no cure for Alzheimer’s, and current treatments are far from perfect, the conclusions of these reviews are good news.
However, the authors of both explain that more research is needed. Drawing solid conclusions will require more investigations into the links between different dietary patterns and Alzheimer’s.
With that said, all of the dietary patterns that appear to reduce Alzheimer’s risk have certain features in common. And they all involve consuming more plants and fewer ultra-processed foods.
So, if you’re considering changing your diet, upping your plant intake is a safe bet. It’s likely to do your health a favor, and it might reduce your Alzheimer’s risk, too.
2023 Alzheimer’s facts and figures. (2023). https://www.alz.org/media/Documents/alzheimers-facts-and-figures.pdf
Association of ultraprocessed food consumption with risk of dementia. Neurology. (2022). https://n.neurology.org/content/99/10/e1056
DASH eating plan. (2021). https://www.nhlbi.nih.gov/education/dash-eating-plan
Dietary fatty acids and risk of Alzheimer's disease and related dementias: Observations from the Washington Heights-Hamilton Heights-Inwood Columbia Aging Project (WHICAP). Alzheimer’s and Dementia. (2020). https://pubmed.ncbi.nlm.nih.gov/32715635/
Dietary pattern in relation to the risk of Alzheimer’s disease: a systematic review. Neurological Sciences. (2019). https://link.springer.com/article/10.1007/s10072-019-03976-3
Effect of nutrition in Alzheimer’s disease: A systematic review. Frontiers in Neuroscience. (2023). https://www.frontiersin.org/articles/10.3389/fnins.2023.1147177/full
Facts for the media about dementia. (2023). https://www.alzheimers.org.uk/about-us/news-and-media/facts-media
High glycemic diet is related to brain amyloid accumulation over one year in preclinical Alzheimer's disease. Frontiers in Nutrition. (2021). https://pubmed.ncbi.nlm.nih.gov/34646853/
Inflammation as a central mechanism in Alzheimer's disease. Alzheimer's & Dementia: Translational Research & Clinical Interventions. (2018). https://www.sciencedirect.com/science/article/pii/S2352873718300490
Is Alzheimer’s genetic? (n.d.). https://www.alz.org/alzheimers-dementia/what-is-alzheimers/causes-and-risk-factors/genetics
Mediterranean diet and risk of dementia and Alzheimer's disease in the EPIC-Spain Dementia Cohort Study. Nutrients. (2021). https://pubmed.ncbi.nlm.nih.gov/33671575/
MIND diet associated with reduced incidence of Alzheimer's disease. Alzheimer’s and Dementia. (2015). https://pubmed.ncbi.nlm.nih.gov/25681666/
Omega-3 fatty acids and neurodegenerative diseases: New evidence in clinical trials. International Journal of Molecular Sciences. (2019). https://www.mdpi.com/1422-0067/20/17/4256
Oxidative stress in Alzheimer’s disease. Neuroscience Bulletin. (2014). https://link.springer.com/article/10.1007/s12264-013-1423-y
Refined carbohydrate-rich diet is associated with long-term risk of dementia and Alzheimer's disease in apolipoprotein E ε4 allele carriers. Alzheimer’s and Dementia. (2020). https://pubmed.ncbi.nlm.nih.gov/32506713/
The DASH diet, 20 years later. JAMA. (2017). https://jamanetwork.com/journals/jama/article-abstract/2611294
The Mediterranean, dietary approaches to stop hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets are associated with less cognitive decline and a lower risk of Alzheimer's disease — a review. Advances in Nutrition. (2019). https://academic.oup.com/advances/article/10/6/1040/5519791
Western diet as a trigger of Alzheimer's disease: From metabolic syndrome and systemic inflammation to neuroinflammation and neurodegeneration. Ageing Research Reviews. (2021). https://pubmed.ncbi.nlm.nih.gov/34214643/
What do we know about diet and prevention of Alzheimer’s disease. (2019). https://www.nia.nih.gov/health/what-do-we-know-about-diet-and-prevention-alzheimers-disease