Eating red meat may increase dementia risk

A new study by researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute has found a significant connection between red meat consumption and dementia risk.

The findings, published in Neurology on January 15, 2025, suggest that eating more red meat, particularly processed forms, could increase the likelihood of developing dementia.

The study also indicates that substituting red meat with healthier protein sources, such as nuts, legumes, or fish, could lower dementia risk by about 20%.

Dr. Daniel Wang, one of the study’s lead authors and a professor at Harvard Chan School, highlights the need to expand dietary guidelines to address brain health.

“Guidelines often focus on heart disease and diabetes, but cognitive health is just as important and closely tied to these conditions,” he said. “Our findings underline the impact of diet on brain health.”

Study Overview and Key Findings

The research analyzed data from two long-term studies: the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS). These studies followed 133,771 participants, averaging 49 years old at the start, for up to 43 years.

During this time, 11,173 participants were diagnosed with dementia. These studies provided detailed information on participants’ diets and lifestyles, updated every two to four years, making it possible to track links between red meat consumption and dementia risk over decades.

The results revealed that consuming processed red meat—such as bacon, hot dogs, and deli meats—was particularly harmful.

Participants who ate at least one-quarter of a serving of processed meat daily (equivalent to two slices of bacon or one hot dog) had a 13% higher risk of developing dementia compared to those eating less than one-tenth of a serving per day.

Similarly, those eating one or more servings of unprocessed red meat daily (like beef, pork, or hamburger) had a 16% higher risk of self-reported cognitive decline compared to those eating less than half a serving per day.

The study also showed that higher consumption of processed meat was associated with faster cognitive aging. For example, eating one serving of processed red meat daily was linked to cognitive aging equivalent to 1.6 additional years.

Potential Biological Mechanisms

While the exact reasons for the link between red meat and dementia are still being studied, researchers point to several possible explanations:

Gut microbiome and TMAO: Red meat is broken down in the gut by bacteria, producing a compound called trimethylamine N-oxide (TMAO). TMAO has been linked to cognitive dysfunction, as it may promote the buildup of amyloid and tau proteins, which are associated with Alzheimer’s disease.
Saturated fat and salt: High levels of saturated fat and salt in red meat could damage brain cells and impair their function.
Inflammation: Red meat may increase inflammation in the body, which is a known risk factor for cognitive decline.

Implications for Diet and Health

The findings suggest that reducing red meat consumption, especially processed forms, could significantly improve long-term cognitive health.

Replacing red meat with alternative protein sources, like nuts, beans, or fish, is not only beneficial for brain health but also helps reduce the risk of chronic diseases such as heart disease and type 2 diabetes.

The study highlights the importance of large, long-term research in understanding conditions like dementia, which develop over many years. Dr. Wang emphasized the need for continued research to uncover the underlying mechanisms linking diet and dementia.

“We’re piecing together how red meat consumption contributes to dementia risk,” he said. “This could lead to better prevention strategies and dietary recommendations.”

For individuals concerned about their cognitive health, incorporating more plant-based proteins and reducing red meat in their diets may be an effective step toward reducing dementia risk and promoting overall well-being.

If you care about brain health, please read studies about vitamin D deficiency linked to Alzheimer’s and vascular dementia, and blood pressure problem at night may increase Alzheimer’s risk.

For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and epilepsy drug may help treat Alzheimer’s disease.

The research findings can be found in Neurology.