research links eating processed red meat to increased risk of dementia and cognitive decline
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processed meats like ham, bacon, hot dogs and sausages that have been modified through salting, curing, fermentation, or smoking, account for a large proportion of the world’s meat consumption.
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if you’re looking to eat healthier for 2025, there’s good reason to lower your red meat consumption—especially processed red meats like bacon, hot dogs and sausage.
mass general brigham researchers in boston have revealed compelling evidence that diets high in processed meats are associated with a 13 per cent higher risk of dementia and cognitive decline in participants followed for up to 43 years.
red meat consumption effects brain health
science has confirmed that eating red meat is an established risk factor for serious chronic conditions like cardiovascular disease and type 2 diabetes, but its effect on brain health hasn’t been widely looked at. as the prevalence of dementia is increasing with the aging population, knowing that diet is a modifiable risk factor could play an important role in solving the burden on healthcare and helping people live longer, independent lives.
if you can eat better to protect your brain and capacity for memory, daily function and problem-solving, that’s powerful medicine.
“we found that the red meat intake, especially the processed red meat intake, meant the risk of dementia is pretty much linear. that means every extra serving or extra amount will bring you additional risk of dementia and cognitive decline,” says study author dr. daniel wang of the channing division of network medicine at brigham and women’s hospital, a founding member of the mass general brigham healthcare system. wang is also an associate member at the broad institute and an assistant professor in nutrition at harvard chan school.
the new study published online in neurology, the medical journal of the american academy of neurology, also highlights that replacing processed red meat with protein sources like nuts and legumes or fish may decrease dementia risk by approximately 20 per cent.
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study data drawn from health-conscious participants
among 133,771 people 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 and health professionals follow-up study, that track thousands of participants’ health and lifestyles. the aim is to identify factors that contribute to risk of chronic diseases like dementia. the studies include decades of detailed health information, including participants’ typical diets, which they update every two to four years.
“this study population is very unique because all the participants are either nurses or physicians, so they are actually a very health-conscious group of people, so their intake level is relatively lower than the average,” wang explains.
reports suggest that americans on average eat 18 pounds of bacon per year, which is about three strips of bacon every week. processed meats like ham, bacon, hot dogs and sausages that have been modified through salting, curing, fermentation, or smoking, account for a large proportion of the world’s meat consumption.
a canadian study in the journal nutrients in 2022 revealed that a “ham and cheese sandwich with lettuce and spread” was among the most frequently consumed processed red meat dishes in canada in 2015, according to the 2015 canadian community health survey. this food item accounted for 41.8 per cent of sodium intake, 31.4 per cent of protein intake, 31 per cent of saturated fat intake, and 21.8 per cent of energy intake among its consumers.
further research on the 2015 canadian community health survey demonstrated that processed meats are among the top 10 contributors to sodium and saturated fat intake of canadians aged one year and older.
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how big is your burger? serving size smaller than you think
a serving of red meat is three ounces or about the size of a deck of cards. dr. wang’s team found that 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 per cent higher risk of developing dementia. the finding was adjusted for clinical, demographic and lifestyle factors including socioeconomic status and family history of dementia.
cognitive function was measured using standard cognitive assessments, showing that this measure was also worse among people with higher processed meat consumption where cognitive aging accelerated by approximately 1.6 years per average daily serving.
wang points out that dietary guidelines typically focus on reducing risks of chronic conditions like heart disease and diabetes, with cognitive health less frequently addressed despite its link to these diseases. he hopes the study results will help policymakers and healthcare providers consider the impact of food choices on brain health.
what happens when you eat bologna and other processed red meats?
“the major kind of harmful components are high saturated fat that can destroy your cholesterol metabolism,” he says of the biochemical reactions needed to break down and use dietary cholesterol in the body. “we also now know very well that high processed red meat intake could lead to insulin resistance [and type 2 diabetes]. then there’s the high salt content, so when you eat more processed red meat, you have higher sodium intake that will increase your blood pressure,” he adds, which can lead to cardiovascular disease.
saturated fat, high salt bad for the heart and the brain
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the saturated fat and salt content of red meat may also harm the health of brain cells. high blood pressure is a predictor of vascular dementia, a type of dementia caused by damage to the brain from impaired blood flow, he says.
the researchers also examined self-reported subjective cognitive decline, which may precede markers of cognitive decline on standard evaluations. a higher risk of subjective cognitive decline was linked to intake of either processed or unprocessed meats like beef, pork and hamburger. subjective cognitive decline risk increased by 14 per cent for those eating one-quarter or more servings of processed meat daily compared to the minimal-consumption group, and the risk jumped by 16 per cent for people eating one or more daily servings of unprocessed meat compared to those eating less than half a serving.
wang plans to continue to explore factors linking red meat with dementia risk, especially factors that involve the gut microbiome. for example, trimethylamine n-oxide (tmao), a product of the bacteria-mediated breakdown of meat in digestion, may increase cognitive dysfunction because of its impact on amyloid and tau proteins that have a role in alzheimer’s disease.
he’s been in the research space for 15 years and says that large, long-term cohort studies like the recent work are essential for investigating conditions like dementia, which can develop over decades.
another key takeaway is swapping in the healthier alternatives suggested in the study paper, wang says. “when you reduce your red meat intake, we also recommend you replace the red meat with chicken, fish, nuts and legumes and low-fat dairy. you can enjoy additional benefits in terms of your cognitive health.”
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