For decades, dietary advice has pushed people toward skim milk, low-fat yogurt and reduced-fat cheeses, often with the quiet message that full-fat dairy belongs on the “eat sparingly” list.

A large Swedish study is now leading to a reconsideration of dairy foods, this time with brain health in focus.

The research published in the journal, Neurology, found that people who regularly eat certain high-fat dairy products, specifically cheese and cream, had a lower risk of developing dementia over time. The findings show an association; they do not prove cause and effect, but they add an unexpected twist to how scientists think about fat, food and the aging brain.

When researchers compared people who ate 50 grams of high-fat cheese daily (about two slices of cheddar) with those who ate less than 15 grams, they found a meaningful difference in rates of dementia.

Researchers, led by Emily Sonestedt, PhD, a nutrition epidemiologist and associate professor at Lund University in Sweden, analyzed data from the Malmo Diet and Cancer Study, one of the world's most detailed population-based nutrition studies. Over 27,600 adults who were an average age of 58 enrolled in the study. Participants were followed for roughly 25 years during which 3,208 people developed dementia.

At baseline, participants kept detailed food records for seven days and completed questionnaires about how often they consumed specific foods over previous years, including how those foods were prepared. This allowed researchers to examine individual dairy categories, including high-fat versus low-fat and fermented versus non-fermented, rather than dairy intake in general.

High-fat cheeses were defined as those containing more than 20 percent fat, including varieties such as cheddar, Brie and Gouda. High-fat creams contained 30 to 40 percent fat, such as whipping cream and double cream.

When researchers compared people who ate 50 grams of high-fat cheese daily (about two slices of cheddar) with those who ate less than 15 grams, they found a meaningful difference. After adjusting for age, sex, education, lifestyle factors and overall diet quality, higher cheese consumption was associated with a 13 percent lower risk of dementia. By the end of the follow-up period, 10 percent of high-cheese consumers developed dementia, compared with 13 percent of the participants who ate very little.

The association was even stronger for vascular dementia, with a 29 percent lower risk among higher cheese consumers. A reduced risk of Alzheimer's disease was also observed, but only among people who did not carry the APOE e4 gene, a known genetic risk factor.

Cream showed a similar pattern. Participants who consumed 20 grams or more of high-fat cream daily (about 1.4 tablespoons) had a 16 percent lower risk of dementia compared with those who consumed none.

Not all dairy products showed this relationship. Low-fat cheese and cream, milk (whether high-or low-fat), butter and fermented milk products, such as yogurt, kefir and buttermilk, were not associated with lowering dementia risk.

Sonestedt emphasized that the findings challenge conventional thinking. “Our study found that some high-fat dairy products may actually lower the risk of dementia, challenging some long-held assumptions about fat and brain, health,” she said in a news release.

The study had important limitations. For instance, all participants lived in Sweden where cheese is often eaten uncooked and typically not paired with processed meats. Eating patterns differ in the United States, where cheese is more likely to appear in ultra-processed foods. This is an important distinction when considering how these results apply to your everyday life.

Cheese eaten with vegetables, whole grains and minimally processed foods tells a different nutritional story from cheese embedded in heavily processed foods.

Rather than dividing foods into “good” or “bad,” the study highlights the importance of context. The researchers are not advising folks to increase their intake of cheese or cream. The takeaway is measured. For those who already enjoy these foods, moderate amounts do not appear harmful and may fit within an overall brain-healthy eating pattern.

Cheese eaten with vegetables, whole grains and minimally processed foods tells a different nutritional story from cheese embedded in heavily processed foods.

As research continues to explore how diet influences the aging brain, this study offers reassurance: familiar foods, enjoyed sensibly and as part of a balanced diet, can still have a place at the table — perhaps even one that supports the mind as well as the palate.

The study is published in Neurology.