Olive Oil for Brain Health: What the Research Actually Shows
Olive oil for brain health has become a headline staple: "a daily spoonful linked to lower dementia risk", "this type of olive oil could boost brain power". Behind those headlines sit a handful of real studies — a large American cohort, two Spanish diet trials, a French population study and one small pilot — and each measured something narrower than the headline suggests. Most found olive oil associated with better outcomes; none proved it protects the brain. Here is what each study actually measured, with its design, size and limits, and what that honestly means for how you eat.
For our own oil, see our cold-pressed organic Marrakech olive oil.
The Short Answer
- The most-quoted finding (Tessier and colleagues, JAMA Network Open, 2024) comes from an observational study of 92,383 US health professionals followed for 28 years: those consuming more than 7 g of olive oil a day had a 28% lower risk of dementia-related death than those who rarely used it. That is an association, not proof of cause.
- Randomised trials exist, but they tested whole Mediterranean diets supplemented with extra virgin olive oil, in older Spaniards at high cardiovascular risk — so the oil's own effect cannot be separated from the diet.
- Grade may matter: a 2026 study of 656 older Spanish adults linked virgin olive oil with better cognitive change over two years, and common (refined-blend) olive oil with faster decline. Again, association only.
- Olive oil is a food, not a brain treatment: a good everyday fat within a healthy diet. If you are worried about your memory, see your GP.
Is Olive Oil Good for Your Brain? The Direct Answer
Olive oil has not been shown to protect the brain. Large observational studies link regular olive oil use with lower dementia-related death and slower cognitive decline, and Mediterranean diets rich in extra virgin olive oil scored slightly better on cognitive tests in Spanish trials. But those links cannot prove cause, and the trials tested whole diets — promising, not proven.
The Headline Study: 28 Years, 92,383 People, One Outcome
Most "olive oil and dementia" stories trace back to one analysis. Tessier and colleagues, in JAMA Network Open in 2024, pooled 92,383 women and men from two long-running US cohorts (the Nurses' Health Study and the Health Professionals Follow-Up Study), all free of cardiovascular disease and cancer at the start. Diet was recorded by questionnaire every four years; over 28 years there were 4,751 dementia-related deaths.
People consuming more than 7 g of olive oil a day — roughly half a tablespoon — had a 28% lower risk of dementia-related death than those who never or rarely used it (hazard ratio 0.72), and the association held after adjusting for the APOE ε4 gene variant and for overall diet quality. In modelled substitutions, replacing 5 g a day of margarine and mayonnaise with olive oil was linked with an 8–14% lower risk; replacing butter or other vegetable oils was not significant.
Three limits matter. It is observational, so people who used olive oil may have differed in ways the adjustments did not capture. The participants were US health professionals, not a cross-section of the population. And the outcome was dementia recorded on death records — not memory, not cognitive tests, not a diagnosis in life.
What the Diet Trials Actually Tested
The randomised evidence comes from PREDIMED, a Spanish trial in older adults at high cardiovascular risk. Participants were assigned a Mediterranean diet supplemented with extra virgin olive oil, the same diet supplemented with mixed nuts, or advice to follow a lower-fat control diet. Two cognitive sub-studies were published.
Martínez-Lapiscina and colleagues, in the Journal of Neurology, Neurosurgery & Psychiatry in 2013, assessed 522 participants in Navarra after 6.5 years of intervention: the olive-oil diet group scored modestly higher than controls on two short tests of global cognition (the Mini-Mental State Examination and a clock-drawing test). Valls-Pedret and colleagues, in JAMA Internal Medicine in 2015, tested 447 cognitively healthy Barcelona volunteers at the start; 334 were retested after a median of 4.1 years. The olive-oil group (about 1 litre a week) did better than controls on frontal and global cognition composites, but not on the memory composite — and much of the gap came from the control group declining.
Both are genuine trials, but neither isolates olive oil: participants changed their whole diet, came from a high-risk Spanish population, and the differences were small.
The Evidence at a Glance
The human studies we verified against their published records:
| Study | Design and size | What it measured | The limit that matters |
|---|---|---|---|
| Berr et al., 2009, Dement Geriatr Cogn Disord | Population cohort; 6,947 older adults in three French cities; 4-year follow-up | Olive oil use (none, moderate, intensive) and cognitive test scores | Brief diet questionnaire; intensive use linked to less decline in visual memory but not verbal fluency |
| Martínez-Lapiscina et al., 2013, J Neurol Neurosurg Psychiatry | Randomised trial (PREDIMED-Navarra); 522 adults at high vascular risk; 6.5 years | Two short global cognition tests after the intervention | Whole-diet intervention; small differences |
| Valls-Pedret et al., 2015, JAMA Intern Med | Randomised trial (PREDIMED Barcelona); 447 enrolled, 334 retested; median 4.1 years | Memory, frontal and global cognition composites | Whole diet; no memory benefit for the olive oil arm; controls declined |
| Kaddoumi et al., 2022, Nutrients | Randomised pilot; 26 adults with mild cognitive impairment (25 completed); 6 months | Extra virgin vs refined olive oil: brain MRI measures, rating scales, blood markers | Tiny, short, no non-olive-oil comparison; the authors call it proof-of-concept |
| Tessier et al., 2024, JAMA Netw Open | Prospective cohorts; 92,383 US health professionals; 28 years | Olive oil intake and dementia-related death | Observational; outcome is death records, not cognition |
| Ni et al., 2026, Microbiome | Prospective cohort (PREDIMED-Plus); 656 adults aged 55–75 with metabolic syndrome; 2 years | Virgin vs common olive oil intake, gut microbiota, cognitive change | Observational; self-reported diet; specific high-risk group |
A 2023 systematic review by Fazlollahi and colleagues in Frontiers in Nutrition found 11 studies in adults over 55 — four cross-sectional, four cohort and three randomised trials — and judged the direction favourable, while calling for larger studies to strengthen the conclusion.
Extra Virgin vs Refined: Why the Grade Keeps Coming Up
The clearest human hint that grade matters is recent. Ni and colleagues, in Microbiome in 2026, followed 656 older Spanish adults with overweight and metabolic syndrome for two years: higher virgin olive oil intake was associated with better cognitive change and a more diverse gut microbiota, while higher intake of common olive oil — the refined-and-blended grade sold as "pure" or "classic" — was associated with faster cognitive decline. Refining strips out most of the polyphenols; our guide to olive oil polyphenols explains what they are.
The small Kaddoumi pilot points the same way on one measure: in 25 people with mild cognitive impairment, only the extra virgin oil changed an MRI measure of blood-brain barrier leakiness over six months — though both oils moved some rating scores. Neither study is proof, and the pilot is no reason to treat any diagnosed condition with olive oil. The modest takeaway is simply to choose extra virgin and keep it fresh.
The Honest Objections
"Twenty-eight years and 92,000 people — surely that settles it?" Size reduces chance; it does not remove confounding. Olive oil users may have differed in ways a questionnaire cannot capture, and the authors themselves describe an association.
"What about the MIND diet, built for the brain?" It is the best reality check. The MIND diet recommends mainly olive oil if added fat is used, and a three-year trial of 604 older adults with a family history of dementia (Barnes and colleagues, New England Journal of Medicine, 2023) found cognition improved in both the MIND group and a control group on the same mild calorie restriction — with no significant difference between them. Diet patterns that look protective in cohorts do not always outperform in trials.
"So is it pointless?" No. Olive oil remains a good everyday fat, and the evidence for the Mediterranean pattern it anchors is strong elsewhere — see our overview of the health benefits of olive oil. It is simply not a brain supplement.
Using Olive Oil Sensibly: A Plain Plan
- Replace, don't add. The substitution findings concerned swapping margarine and mayonnaise for olive oil — not adding oil on top of an unchanged diet.
- Keep amounts ordinary and use it on plants. The associations appeared from about 7 g a day; our guide to how much olive oil per day covers what studies used. Dress greens, beans and vegetables with it.
- Choose extra virgin and store it well. Dark glass, away from the hob, used within a few months of opening.
If you are worried about your memory, or someone close to you, the NHS advice is clear: it is a good idea to see a GP. Food is not the right tool for new symptoms.
Why Sidr & Stone
We will not tell you our olive oil is good for your brain — no olive oil has earned that claim. Olive oil is honoured in the Prophetic Sunnah (our guide to olive oil in the Quran and the Sunnah covers the texts), and we treat that heritage with care rather than as a health promise. What we can tell you is exactly what is in the bottle.
- Sidr & Stone's olive oil comes from a single estate — our own family-owned farm on the plains outside Marrakech, Morocco — with every step from tree to bottle under our control and no blending across origins.
- The grove is rain-fed, with no irrigation; the trees take what the season gives.
- It is organically grown, with no synthetic fertilisers, pesticides or herbicides; certification is in progress, as disclosed below.
- It is a limited single-harvest batch, picked when the fruit is ready and cold-pressed within hours of harvest to preserve flavour, aroma and polyphenols.
- It is unfiltered extra virgin olive oil, so natural sediment may settle — normal for an unfiltered oil.
- It is 100% natural: one ingredient, olive oil, nothing added.
- It comes in 500ml dark glass with a gold label, which helps protect the oil from light.
- Sidr & Stone gives 10% of profits to charity, with fulfilment in the UK, EU, and US.
We will not tell you Sidr & Stone is the best olive oil for your brain — that would be the very claim this article warns against. What we will say is that our oil is single-estate Moroccan, rain-fed, organically grown and cold-pressed within hours of harvest. We have not yet published lab figures for polyphenols, so we make no claim about them.
Frequently Asked Questions
Is olive oil good for brain health?
It is a good everyday fat, but it has not been shown to protect the brain. Large observational studies link it with lower dementia-related death and slower cognitive decline, and Mediterranean diet trials with extra virgin olive oil showed small test-score differences — association and whole-diet effects, not proof.
How might olive oil affect the brain?
Researchers are studying its polyphenols, its monounsaturated fat and its links with gut bacteria — hypotheses largely from animal and laboratory work, not established mechanisms in people.
How much olive oil did the studies use?
The US cohort compared more than 7 g a day with rare use; the Barcelona trial supplied about 1 litre a week. Treat olive oil as your main cooking and dressing fat, not a dose.
Is extra virgin better than regular olive oil for the brain?
Limited evidence leans that way: one 2026 cohort linked virgin olive oil with better cognitive change and common olive oil with faster decline. That is an association, not a proven difference.
Can olive oil prevent dementia or Alzheimer's?
No study has shown that. If you are worried about your memory or dementia risk, speak to your GP, who can discuss the factors that are known to matter.
Is drinking a shot of olive oil better for the brain?
There is no evidence that it is; the studies looked at olive oil eaten with food. Our article on drinking olive oil covers the practical side.
Where can I buy Sidr & Stone olive oil?
Our cold-pressed organic Marrakech olive oil is on pre-order from a limited single-harvest batch, with estimated shipping from November 2026 and fulfilment in the UK, EU, and US.
Is olive oil a medicine?
No. Olive oil is a food, not a medicine. It has a long traditional history — including being honoured in the Prophetic Sunnah — and a substantial body of modern research, particularly around polyphenols, cardiovascular health, and the Mediterranean diet pattern. It can be a worthwhile part of a healthy routine, but it does not cure diseases and is not a substitute for medical care. Be cautious of any olive oil marketed with specific disease-cure claims.
Final Thoughts
The research on olive oil and the brain consistently points in a favourable direction. It is also, every time, either observational or about a whole diet, and a three-year trial of the brain-focused MIND diet found no edge over a control diet. Olive oil is neither a brain remedy nor a gimmick; fresh extra virgin olive oil, used in place of less favourable fats on a plant-rich plate, is a sensible habit on current evidence. Concerns about memory belong with your GP.
Our cold-pressed organic Marrakech olive oil — single-estate, rain-fed and pressed within hours of harvest — is available to pre-order from the current single-harvest batch, with fulfilment in the UK, EU, and US. For how to judge any bottle, see our guide to choosing a quality olive oil.
Our extra virgin olive oil is grown organically on our own single-estate farm on the plains outside Marrakech: we control every step from tree to bottle, and no synthetic pesticides, herbicides or fertilisers are used. It is not yet certified organic — certification is in progress, and we will publish it as soon as it comes through.
Pre-Order Sidr & Stone Organic Marrakech Olive Oil — Limited Single-Harvest Batch →
Disclaimer: This article describes published research on olive oil and brain health at the time of writing; research findings may change, and readers should check current sources. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.