Neurologist: Lifestyle changes could cut Alzheimer's risk by 50%

José Miguel Laímez, who leads the neurology department at Hospital Universitario Casa de Salud in Valencia, has a straightforward argument: the way we live from childhood onward determines much of what happens to our brains in old age. Speaking at a neuroscience journalism conference in May, he laid out the evidence that deliberate changes to how we eat, move, think, and connect could cut the risk of Alzheimer's disease and other dementias by half—and reduce strokes by an even larger margin.

The scale of the problem is immense. Fifty-seven million people worldwide live with dementia today. It ranks as the seventh leading cause of death globally and one of the primary drivers of disability and dependency. Strokes kill and disable even more people—93.8 million cases estimated annually, making them the third leading cause of death and disability on the planet. Yet Laímez's point was not to despair at these numbers but to recognize that many of these conditions are not inevitable. They can be prevented or delayed by acting on factors we can actually control.

The concept that anchors his argument is cognitive reserve—the brain's capacity to withstand injury, disease, and aging because it has built a richer, more densely connected network of neurons. Some of this reserve comes from genetics, but much of it can be built deliberately. Education matters. Intellectual work matters. Physical activity matters. Healthy habits matter. Learning new things throughout life matters. Speaking multiple languages matters. All of these things, layered together from childhood forward, create a brain that is more resilient, more able to tolerate the biological assaults that come with time.

The practical toolkit Laímez described is not exotic. Mediterranean diet—olive oil, fish, legumes, vegetables, fruit, nuts, moderate wine—because the brain consumes roughly one-fifth of the body's energy and is exquisitely sensitive to what it is fed. Omega-3 fatty acids, folate, magnesium, and other micronutrients matter. Sleep quality matters. Social connection and the absence of isolation matter. Avoiding tobacco and excessive alcohol matters. Limiting screen time matters, especially for young people, though adults are not immune to its effects.

But if there is a single intervention that Laímez described as closest to a fountain of youth, it is exercise. Clinical trials show that one year of aerobic activity increases the volume of the hippocampus, the brain region critical to memory. Longer studies confirm that more physical activity correlates with less cognitive and functional decline, even in people who already have amyloid buildup in their brains—the hallmark of Alzheimer's pathology. Exercise appears to reduce the accumulation of tau protein, which is more directly linked to the clinical symptoms of dementia. People who are physically active live longer, have lower mortality rates, and enjoy roughly five additional years of life compared to those who are sedentary. Laímez's recommendation is straightforward: frequent aerobic exercise combined with strength training at least once weekly, with balance work added for older adults to prevent falls. Ten thousand steps a day is the target he cited.

One point of contention emerged in his remarks. Laímez defended moderate alcohol consumption—a beer with friends after work, he said, is not the same as drinking alone to console oneself—citing the so-called J-curve relationship between alcohol and dementia, which suggests that low doses might be neutral or even protective. This position diverges from the direction of major public health campaigns and scientific societies, which increasingly advocate for zero alcohol as the safest message. The debate reflects genuine uncertainty in the evidence, though the trend in global health guidance is toward caution.

The larger point, though, is one of agency. Laímez was arguing that the brain is not a fixed organ that simply deteriorates with age. It is something that can be built, maintained, and protected through choices made across a lifetime. The window for intervention is not a single moment but an entire lifespan—from childhood education and intellectual stimulation through old age and continued learning. The stakes are enormous: if even a fraction of the fifty percent reduction in dementia risk he cited could be achieved at a population level, millions of people would be spared the loss of memory, independence, and self that defines these diseases.