Does olive oil protect your brain against decline?
Olive oil as part of the Mediterranean diet is associated with a lower risk of dementia. Whether olive oil itself makes the difference cannot be established on the basis of current research.
Extra virgin olive oil (EVOO) showed a small but measurable improvement in cognitive test scores in older people with mild cognitive impairment or dementia, based on a combined analysis of five small studies. The researchers themselves rate the certainty of this evidence as low, and they point out that the studies are too small to support firm conclusions. Whether that improvement means anything noticeable in everyday life has not yet been established.
Olive oil is rarely studied in isolation from an overall dietary pattern. What we do know is that people who consistently follow the Mediterranean diet, in which olive oil plays a central role, have up to 30% lower odds of developing Alzheimer's disease and 11% lower odds of dementia in general. That sounds impressive, but it reflects an association: people who eat this way also live differently in many other respects. It has not been proven that the diet itself is the cause.
When it comes to brain scans, the picture is mixed. Certain compounds in olive oil appear to modestly improve blood flow to the brain. But effects on brain structure itself, such as the volume of the memory region, are far from consistently found. Several studies came up empty.
For anyone already following the Mediterranean diet or considering it: the signals are positive enough to regard it as part of a healthy lifestyle. Olive oil as the sole addition to an otherwise unhealthy diet has no proven brain-protective effect.
This answer draws on multiple combined analyses of existing studies, including two that specifically assessed the quality of the evidence. The researchers behind the extra-virgin olive oil work themselves state that the certainty of the evidence is low, and that the small number of participants makes the findings less reliable. A second group of researchers echoes that judgement: low certainty, small samples and unclear real-world significance all call for caution. The Mediterranean diet studies are larger and more consistent, but they measure association only, not cause and effect. In addition, the variation between the individual studies is considerable, which makes the combined results less definitive.
Does regular sauna use protect your brain against decline?
People who used a sauna four to seven times a week developed dementia considerably less often in long-running research than people who went once a week, but whether sauna is the cause is unknown. If you already exercise regularly and have a healthy lifestyle, using the sauna more often is an accessible addition with a plausible biological rationale.
Do brain-training games help prevent cognitive decline?
Brain-training games give healthy older adults at most a temporary and small boost on test scores, but that effect fades over time. People who enjoy them take little risk, but high expectations are not warranted.
Which lifestyle habits protect your brain health over the long term?
Cognitive activities, a plant-based dietary pattern, and regular exercise, preferably in combination, offer the best-supported protection for your brain over the long term. Hard cause-and-effect evidence is still lacking, but the associations are broad and consistent enough to take seriously.
What does an omega-3 deficiency do to your brain and mental resilience?
An omega-3 deficiency demonstrably harms the brain, especially during early development and in depression. If you have symptoms of low mood and are already taking antidepressants, omega-3 as an adjunct is the best-supported option; for Alzheimer's prevention, supplementation offers very little.
Do your brains really shrink as you get older?
Your brain does indeed shrink with age, particularly in areas involved in memory and planning. High blood pressure accelerates that process, while exercise and cognitive effort strengthen your brain's compensatory activity.
Does years of insufficient sleep damage your brain?
Years of insufficient sleep damages the brain through multiple pathways at once, and some of that damage appears difficult or impossible to reverse. Make sure you consistently get enough sleep, and have sleep apnoea treated if you have symptoms of it.