Red meat consumption is an established risk factor for chronic conditions, including cardiovascular disease and type 2 diabetes. According to a new study by researchers at Mass General Brigham, the Harvard TH Chan School of Public Health and the Broad Institute of MIT and Harvard found that eating higher amounts of red meat, especially in processed forms, also increased the risk of dementia. Results, published online January 15, 2025, in Neurology®the medical journal of the American Academy of Neurology, emphasizes that replacing processed red meat with protein sources such as nuts and legumes or fish can reduce the risk of dementia by about 20 percent.
“Dietary guidelines tend to focus on reducing the risks of chronic conditions such as heart disease and diabetes, while cognitive health is discussed less often, despite being linked to these diseases,” says corresponding author Daniel Wang, MD, ScD, of the Channing Division of Network Medicine at Brigham and Women’s Hospital, a founding member of the Mass General Brigham health care system.
Wang is also an associate member at the Broad Institute and an assistant professor in the Department of Nutrition at Harvard Chan School. “We hope our results will encourage more attention to be paid to the link between diet and brain health.”
As the U.S. population ages, dementia poses a growing challenge for patients and families. Of the 133,771 individuals included in this study who had a mean age of 49 years at baseline, 11,173 were diagnosed with dementia up to 43 years later. Data comes from the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS), which prospectively study the health and lifestyle of thousands of participants, which may influence the risk of chronic diseases such as dementia. The studies include decades of detailed health information, including participants’ typical diets, which they update every 2 to 4 years.
A typical serving of red meat is 90 grams – about the size of a bar of soap. Those who eat an average of one-quarter or more of a serving of processed red meat daily (about two slices of bacon, one and a half slices of bologna, or a hot dog), compared to those who consume a minimal amount (less than one-tenth of a serving per day) had a 13 percent higher risk of developing dementia, adjusted for numerous clinical, demographic and lifestyle factors such as socioeconomic status and family history of dementia.
The researchers measured objective cognitive function using standard cognitive assessments. They found that this measure was also worse among those with greater consumption of processed meat, with cognitive aging accelerating by about 1.6 years per average daily serving.
The researchers also examined self-reported subjective cognitive decline (SCD), which may precede markers of cognitive decline according to standard assessments. A greater risk of SCD was associated with the consumption of processed or unprocessed meats (such as beef, pork and hamburgers). The risk of cardiovascular disease increased by 14 percent for those who ate a quarter or more servings of processed meat daily compared to the group that consumed minimally, and by 16 percent for those who ate one or more servings of unprocessed meat daily compared to those who consumed ate less than half. portion.
The researchers continue to investigate factors linking red meat to dementia risk, especially those involving the gut microbiome. Trimethylamine N-oxide (TMAO), a product of the bacteria-mediated breakdown of meat, may increase cognitive dysfunction due to its effects on the aggregation of amyloid and tau, proteins involved in Alzheimer’s disease, but the research is limited. The saturated fat and salt content of red meat can also affect the health of brain cells.
Large, long-term cohort studies are essential for investigating conditions such as dementia, which can develop over decades. We continue to piece this story together to understand the mechanisms that drive dementia and cognitive decline.”
Daniel Wang, MD, ScD, of the Channing Division of Network Medicine, Brigham and Women’s Hospital
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Magazine reference:
Li, Y., et al. (2025). Long-term red meat intake in relation to dementia risk and cognitive function in US adults. Neurology. doi.org/10.1212/wnl.0000000000210286.