Which lifestyle habits protect your brain health over the long term?

Staying cognitively active is one of the most thoroughly studied protective habits. Older adults who regularly read, play board games, play a musical instrument, or dance had a 7% lower dementia risk per step up on the activity scale in a cohort study of people aged 75 and over. This effect held up after people with early, not-yet-diagnosed dementia were removed from the analysis. This is an observational finding, not proof of cause and effect, but the association is strikingly consistent.

What you eat also appears to matter. The MIND diet, a combination of the Mediterranean and DASH dietary patterns specifically focused on brain nutrition, was associated in observational research with cognitive performance comparable to that of people who were on average 7.5 years younger, measured over nearly five years. The pattern is rich in vegetables, nuts, fish, and olive oil, and low in red meat and processed products. The combination appears to work more strongly than either diet individually. Direct causality has not yet been demonstrated in large randomised trials.

Exercise likely protects the brain through several pathways simultaneously: it helps clear harmful proteins, suppresses inflammation, stimulates growth factors for nerve cells, and improves blood flow to the brain. Notably, in one randomised trial involving one hundred people with mild memory complaints, six months of intensive resistance training protected specific brain regions that normally shrink rapidly in Alzheimer's disease. That protective effect was still measurable even one year after training had stopped. Pure aerobic exercise or cognitive computer games alone did not produce that long-term effect in the same study. The study is too small for firm conclusions, but the result is worth keeping in mind.

In one cohort study of people aged 75 and over, greater physical activity on its own was not measurably associated with a lower dementia risk. This is noteworthy, but it is likely a methodological artefact: the study was not specifically designed for this purpose and the participants were already relatively old and not very active. Broader reviews do describe exercise as a recognised protective factor, so this single negative result is not a reason to remain inactive.

Herbal supplements and medicinal plant extracts are sometimes promoted as a supplement for cognitive decline. Research in this area consists largely of small or preclinical studies. Large, well-designed clinical trials are lacking, and concrete recommendations cannot be made on the basis of the available evidence.