A recent study published in the medical journal Neurology revealed a link between the consumption of processed red meat and an increased risk of dementia and cognitive decline. The research analyzed health and nutrition data from 133,771 individuals, with an average age of 49 years at the start of the study, collecting detailed health information every two to four years.
Participants consuming at least a quarter serving of processed meat daily—equivalent to two slices of bacon or one hot dog—faced a higher risk of dementia compared to those with minimal intake. Specifically, the risk of subjective cognitive decline (SCD) increased by 14% for those consuming a quarter or more servings of processed red meat daily, with a relative risk of 1.14.
"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," said Dr. Daniel Wang, an assistant professor of medicine at Brigham and Women's Hospital and Harvard Medical School, according to a report by SciTechDaily.
The researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard University conducted the study over a span of up to 43 years. Among the participants, 11,173 were diagnosed with dementia during the follow-up period. The findings suggest that higher consumption of processed red meat is associated with accelerated brain aging and a decline in overall brain function.
Each additional daily serving of processed red meat was linked to a 1.61-year acceleration in brain aging and a 1.61-year decline in overall brain function. The study also found that substituting processed red meat with fish was linked to a 28% lower risk of dementia. Replacing processed red meat with plant-based protein sources such as nuts, legumes, or fish could lead to a 20% lower risk of dementia.
"Reducing red meat consumption and replacing it with other protein sources and plant-based options should be included in dietary guidelines to promote cognitive health," emphasized Dr. Dong Wang.
Subjective cognitive decline refers to a person reporting worsening memory and thinking problems before any decline is substantial enough to appear on standard tests. In the study, participants assessed their cognitive function through yes-or-no questions about memory difficulties.
The possible mechanisms behind the association were explored. The researchers hypothesized that saturated fats and salt in red and processed meats may impair brain cells' health, potentially harming their function. Compounds like trimethylamine N-oxide (TMAO), produced during the digestion of red meat, may increase cognitive dysfunction due to their effects on the aggregation of amyloid and tau proteins involved in Alzheimer's disease.
Despite these findings, the study's scope was primarily limited to white healthcare professionals, which means the results may not fully apply to other racial, ethnic, or gender-diverse groups. "More research is needed to assess our findings in more diverse groups," said Dr. Dong Wang.
Participants completed food diaries every two to four years, recording their dietary intake, including more than 150 foods. For processed red meat, they were divided into three groups: low (fewer than 0.10 daily servings), medium (0.10 to 0.24 daily servings), and high (0.25 or more servings per day). A serving of red meat was defined as approximately 85 grams, about the size of a bar of soap.
To measure objective cognitive function, the study included 17,458 female participants with an average age of 74. These participants underwent standardized cognitive assessments that evaluated memory, recall, and cognitive abilities at various points throughout the study.
"We hope our results encourage greater consideration of the connection between diet and brain health," concluded Dr. Daniel Wang, according to a report by EurekAlert.
This article was written in collaboration with generative AI company Alchemiq