Summary: A study of over 133,000 individuals found that consuming processed red meat daily increases dementia risk by up to 13%, while replacing it with alternatives like nuts, legumes, or fish may lower the risk by 20%. Higher processed meat intake was associated with accelerated cognitive aging and increased subjective cognitive decline (SCD).
Researchers suggest that saturated fats, salt, and gut microbiome changes, including TMAO production, may link red meat to dementia risk. These findings emphasize the importance of dietary choices for both physical and cognitive health, highlighting the potential to reduce dementia risk through simple dietary changes.
Key Facts:
- Dementia Risk: Consuming processed red meat daily raises dementia risk by 13%, with cognitive aging accelerated by 1.6 years per serving.
- Protective Alternatives: Replacing processed red meat with nuts, legumes, or fish reduces dementia risk by 20%.
- Gut-Brain Link: Red meat’s impact on the gut microbiome, including TMAO production, may contribute to cognitive dysfunction.
Source: Mass General
Red meat consumption is an established risk factor for chronic conditions, including cardiovascular disease and type 2 diabetes.
A new study by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard found that eating greater quantities of red meat, especially in processed forms, increased risk for dementia, too.
Results, published online on January 15, 2025 in Neurology, the medical journal of the American Academy of Neurology, highlight that replacing processed red meat with protein sources like nuts and legumes or fish may decrease dementia risk by approximately 20 percent.
Video Credit: Neuroscience News
“Dietary guidelines tend to focus on reducing risks of chronic conditions like heart disease and diabetes, while cognitive health is less frequently discussed, despite being linked to these diseases,” said 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 encourage greater consideration of the connection between diet and brain health.”
As the U.S. population ages, dementia represents a growing challenge for patients and families. Among 133,771 individuals included in this study with an average age of 49 years at baseline, 11,173 were diagnosed with dementia up to 43 years later.
Data were drawn from the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS), which prospectively study thousands of participants’ health and lifestyles, which may influence risk of chronic diseases like 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 3 ounces — approximately the size of a bar of soap. Those eating a daily average of one-quarter or more of a serving of processed red meats (roughly two slices of bacon, one and half slices of bologna, or a hot dog), compared to those consuming a minimal amount (less than one-tenth a serving each day), had a 13 percent higher risk of developing dementia, adjusting 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 processed meat consumption, with cognitive aging accelerated by approximately 1.6 years per average daily serving.
The researchers also examined self-reported subjective cognitive decline (SCD), which may precede markers of cognitive decline on standard evaluations. A greater risk of SCD was associated with consuming either processed or unprocessed meats (like beef, pork and hamburger).
SCD risk increased by 14 percent for those eating one-quarter or more servings of processed meat daily compared to the minimal-consumption group, and by 16 percent for those eating one or more daily servings of unprocessed meat compared to those eating less than half a serving.
The researchers are continuing to explore factors linking red meat with 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 research is limited.
The saturated fat and salt content of red meat may also impair brain cells’ health.
“Large, long-term cohort studies are essential for investigating conditions like dementia, which can develop over decades,” Wang said.
“We are continuing to piece together this story to understand the mechanisms causing dementia and cognitive decline.”
Funding: This study was supported by the National Institutes of Health (R01AG077489, RF1AG083764, R00DK119412, R01NR019992, and P30DK046200).
About this diet and dementia research news
Author: Brandon Chase
Source: Mass General
Contact: Brandon Chase – Mass General
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Long-Term Intake of Red Meat in Relation to Risk of Dementia and Cognitive Function in US Adults” by Yanping Li et al. Neurology
Abstract
Long-Term Intake of Red Meat in Relation to Risk of Dementia and Cognitive Function in US Adults
Background and Objectives
Previous studies have shown inconsistent associations between red meat intake and cognitive health. Our objective was to examine the association between red meat intake and multiple cognitive outcomes.
Methods
In this prospective cohort study, we included participants free of dementia at baseline from 2 nationwide cohort studies in the United States: the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS). Diets were assessed using a validated semiquantitative food frequency questionnaire.
We ascertained incident dementia cases from both NHS participants (1980–2023) and HPFS participants (1986–2023). Objective cognitive function was assessed using the Telephone Interview for Cognitive Status (1995–2008) among a subset of NHS participants. Subjective cognitive decline (SCD) was self-reported by NHS participants (2012, 2014) and HPFS participants (2012, 2016).
Cox proportional hazards models, general linear regression, and Poisson regression models were applied to assess the associations between red meat intake and different cognitive outcomes.
Results
The dementia analysis included 133,771 participants (65.4% female) with a mean baseline age of 48.9 years, the objective cognitive function analysis included 17,458 female participants with a mean baseline age of 74.3 years, and SCD analysis included 43,966 participants (77.1% female) with a mean baseline age of 77.9 years.
Participants with processed red meat intake ≥0.25 serving per day, compared with plinearity plinearity = 0.004).
Higher processed red meat intake was associated with accelerated aging in global cognition (1.61 years per 1 serving per day increment [95% CI 0.20–3.03]) and in verbal memory (1.69 years per 1 serving per day increment [95% CI 0.13–3.25], both plinearity = 0.03). Unprocessed red meat intake of ≥1.00 serving per day, compared with plinearity = 0.04).
Replacing 1 serving per day of nuts and legumes for processed red meat was associated with a 19% lower risk of dementia (HR 0.81, 95% CI 0.75–0.86), 1.37 fewer years of cognitive aging (95% CI −2.49 to −0.25), and a 21% lower risk of SCD (RR 0.79, 95% CI 0.68–0.92).
Discussion
Higher intake of red meat, particularly processed red meat, was associated with a higher risk of developing dementia and worse cognition. Reducing red meat consumption could be included in dietary guidelines to promote cognitive health. Further research is needed to assess the generalizability of these findings to populations with diverse ethnic backgrounds.
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