A Swedish study suggests that people who regularly eat high-fat cheese may have a slightly lower risk of developing dementia. The findings attracted a lot of attention after a report by The New York Times. But how robust is the research – and should it influence what we eat? The debate began with a large Swedish observational study published at the end of 2025 in the journal Neurology. Researchers followed nearly 28,000 people for about 25 years. They found that participants who consumed the most high-fat cheese had a 13% lower risk of dementia than those who consumed the least. At first glance, the result sounds promising. But nutrition research rarely offers simple answers. An association, not proof The key point is that this is an observational study. It tracks dietary habits and health outcomes over time, but does not intervene. As a result, it can identify correlations, not cause-and-effect relationships. “Using a single observational study to change your diet is like ...
