MINNEAPOLIS — People who eat more red meat, especially processed red meat like bacon, sausage and bologna, are more likely to have a higher risk of cognitive decline and dementia when compared to those who eat very little red meat, according to a study published in the January 15, 2025, online issue of Neurology®, the medical journal of the American Academy of Neurology.
“Red meat is high in saturated fat and has been shown in previous studies to increase the risk of type 2 diabetes and heart disease, which are both linked to reduced brain health,” said study author Dong Wang, MD, ScD, of Brigham and Women’s Hospital in Boston. “Our study found processed red meat may increase the risk of cognitive decline and dementia, but the good news is that it also found that replacing it with healthier alternatives, like nuts, fish and poultry, may reduce a person’s risk.”
To examine the risk of dementia, researchers included a group of 133,771 people with an average age of 49 who did not have dementia at the start of the study. They were followed up to 43 years. Of this group, 11,173 people developed dementia.
Participants completed a food diary every two to four years, listing what they ate and how often.
Researchers defined processed red meat as bacon, hot dogs, sausages, salami, bologna and other processed meat products. They defined unprocessed red meat as beef, pork, lamb and hamburger. A serving of red meat is three ounces, about the size of a deck of cards.
Researchers calculated how much red meat participants ate on average per day.
For processed red meat, they divided participants into three groups. The low group ate an average of fewer than 0.10 servings per day; the medium group ate between 0.10 and 0.24 servings per day; and the high group, 0.25 or more servings per day.
After adjusting for factors such as age, sex and other risk factors for cognitive decline, researchers found that participants in the high group had a 13% higher risk of developing dementia compared to those in the low group.
For unprocessed red meat, researchers compared people who ate an average of less than one half serving per day to people who ate one or more servings per day and did not find a difference in dementia risk.
To measure subjective cognitive decline, researchers looked at a different group of 43,966 participants with an average age of 78. Subjective cognitive decline is when a person reports memory and thinking problems before any decline is large enough to show up on standard tests.
The subjective cognitive decline group took surveys rating their own memory and thinking skills twice during the study.
After adjusting for factors such as age, sex and other risk factors for cognitive decline, researchers found that participants who ate an average of 0.25 servings or more per day of processed red meat had a 14% higher risk of subjective cognitive decline compared to those who ate an average of fewer than 0.10 servings per day.
They also found people who ate one or more servings of unprocessed red meat per day had a 16% higher risk of subjective cognitive decline compared to people who ate less than a half serving per day.
To measure objective cognitive function, researchers looked at a different group of 17,458 female participants with an average age of 74. Objective cognitive function is how well your brain works to remember, think and solve problems.
This group took memory and thinking tests four times during the study.
After adjusting for factors such as age, sex and other risk factors for cognitive decline, researchers found that eating higher processed red meat was associated with faster brain aging in global cognition with 1.61 years with each additional serving per day and in verbal memory with 1.69 years with each additional serving per day.
Finally, researchers found that replacing one serving per day of processed red meat with one serving per day of nuts and legumes was associated with a 19% lower risk of dementia and 1.37 fewer years of cognitive aging. Making the same substitution for fish was associated with a 28% lower risk of dementia and replacing with chicken was associated with a 16% lower risk of dementia.
“Reducing how much red meat a person eats and replacing it with other protein sources and plant-based options could be included in dietary guidelines to promote cognitive health,” said Wang. “More research is needed to assess our findings in more diverse groups.”
A limitation of the study was that it primarily looked at white health care professionals, so the results might not be the same for other race, ethnic and non-binary sex and gender populations.
The study was supported by the National Institutes of Health.
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