Eating more high-fat cheese and cream may be associated with a lower risk of developing dementia, according to a study published on December 17 in the academic journal Neurology. The analysis — based on data collected from nearly 30,000 people — challenges the previous scientific belief that a low-fat diet could have a protective effect against dementia. Although its conclusions are quite dramatic, it’s an observational study that doesn’t prove causation.
“For decades, the debate over high-fat versus low-fat diets has shaped health advice: [some have categorized] cheese as an unhealthy food that should be limited,” says Emily Sonestedt, an epidemiologist at Lund University in Sweden and lead author of the study. “Our study found that some high-fat dairy products may, in fact, reduce the risk of dementia, challenging some long-held assumptions about brain health.”
Researchers analyzed data from 27,670 people in Sweden, with an average age of 58 at the start of the study. At that time, participants recorded their food intake for one week and answered questions about how frequently they had consumed certain foods in recent years. They were then followed for an average period of 25 years. During this time, 3,208 of the participants developed dementia. After adjusting for age, gender, education and overall diet quality, the researchers found that people who reported consuming more high-fat cheese had a 13% lower risk of developing dementia than those who consumed less. High-fat cheeses are those containing more than 20% fat: Manchego, Parmesan, Roquefort and cheddar fall into this category.
Naveed Sattar, a professor of cardiometabolic medicine and an honorary consultant physician at the University of Glasgow, is highly critical of the study. Speaking to the science website SMC, he begins by pointing out that the research doesn’t demonstrate causality. He also explains that there may be a variable to consider: the people who consumed more cheese had, on average, a higher level of education. “This raises the possibility of residual confounding,” he adds. Therefore, the expert doesn’t believe this study will change the paradigm regarding fats and dementia.
“We already know of several well-established and proven factors that reduce dementia risk, such as maintaining healthy blood pressure, managing weight, and preventing heart disease or stroke. These interventions should remain the priority, given their strong evidence base, rather than focusing on unproven dietary associations,” Sattar notes.
Also speaking to SMC, Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh, expresses a similar view. The neurologist believes that “while these are interesting data, this type of study cannot determine whether this association of reduced dementia risk was caused by the differences in cheese consumption.” Spires-Jones also highlights a detail: the subjects only provided details about their diet at the beginning of the study. Since a person’s diet changes over the course of 25 years, this means that the study’s conclusions become less relevant. Finally, she emphasizes the importance of maintaining a healthy diet and reminds us that “there isn’t strong evidence for any individual food protecting people from dementia.”
Dementia is a growing disease. In an aging world, its incidence continues to rise. The scientific community estimates that, by 2050, the number of people living with dementia worldwide will almost triple, increasing from 57 million in 2019 to 153 million within three decades. Age and genetics are the main risk factors for developing it, hence why there’s little room for prevention. However, there are a few environmental factors that could predispose someone to developing dementia.
In the summer of 2024, the Lancet Commission on Dementia published a report suggesting that almost half of all dementias — 45%, according to the study’s models — could be avoided or delayed if 14 preventable risk factors closely linked to their development were eliminated. These included diabetes and high cholesterol.
Excess LDL cholesterol — known as “bad” cholesterol — may be responsible for 7% of dementia cases, according to the 2024 study. And high-fat cheeses are among the foods that most significantly increase LDL levels. Excess cholesterol in the brain is associated with a higher risk of stroke and the deposition of beta-amyloid and tau proteins, which are strongly linked to the development of Alzheimer’s disease.
This topic has been extensively studied, although the findings are inconclusive. A meta-analysis by Peking University, which included nine studies and more than 23,000 participants, reached similar conclusions as the Lancet Commission. Higher consumption of saturated fats (such as those found in fatty cheeses and cream) was associated with a greater risk of cognitive decline and Alzheimer’s. Even so, the methodological diversity used across the various studies makes it necessary to interpret these conclusions with caution.
While all experts point to the importance of lifestyle and healthy choices for maintaining optimal brain health, most of what determines whether a person develops dementia is beyond their control. Experts caution against assuming that people with dementia could have avoided it by choosing a different lifestyle, as this notion is a mere hypothesis based on observational evidence. In reality, there’s no conclusive, causal evidence that dementia can be prevented through diet… much less by promoting the consumption or avoidance of any specific food.
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