Eating even a small amount of processed meat every day is associated with a higher risk of dementia, according to a large scientific review examining the impact of ultra-processed foods on brain health.
Scientists from 26 scientific institutions analyzed more than 170 studies involving more than 500,000 people. The results were published in the Annual Review of Nutrition.
One of the strongest associations was found with processed meat. Every additional 25 grams per day was associated with a 44 to 52 percent higher risk of dementia.
This amount is roughly equivalent to two thin slices of deli turkey, one strip of bacon or half a hot dog.
The authors emphasize that the result shows a statistical association, but does not prove that processed meat causes dementia.
“Some of the data is alarming, but there are still many questions about how these associations work and what they mean for cognitive health in the long term,“ commented Dr. Owen Carmichael of the Pennington Biomedical Research Center at Louisiana State University.
Scientists still do not know exactly what mechanisms are behind the observed association. One hypothesis is related to the preservatives in processed meat, including nitrates, as well as the high salt, saturated fat and other components.
How processed foods may affect the brain
These could potentially contribute to inflammatory processes and blood vessel damage, which over time can affect brain function.
The review found an overall higher risk of dementia among people who consume more ultra-processed foods.
Among the studies cited is a study of more than 10,000 adults in Brazil. Over an eight-year period, people who got more than 20% of their daily calories from ultra-processed foods showed faster declines in memory and reasoning.
Another analysis of data from the UK Biobank found that replacing 10% of calories from ultra-processed foods with unprocessed or minimally processed foods was associated with a 19% lower risk of dementia.
For better brain health, researchers are focusing on eating patterns that are higher in vegetables, fruits, berries, nuts, legumes, whole grains, and fish. A similar approach underlies the Mediterranean and MIND diets.
However, scientists caution that limiting sausages and other processed meats cannot be considered a proven stand-alone method for preventing dementia. The risk depends on multiple factors, and further research is needed to establish a cause-and-effect relationship.