Steak, hamburgers, beef ribs and hot dogs are bad for the aging brain.

Folks who eat lots of red and processed meat are more likely to develop dementia, researchers reported.

Eating more than one serving of red meat a day — 3 ounces, about the size of a bar of soap — is associated with a 16% increased risk of cognitive decline, researchers found.

And eating more than a daily quarter-serving of processed red meat — bacon, sausage, hot dogs and the like — increased dementia risk by 13% and risk of cognitive decline by 14%.

What’s more, people’s brains appear to age faster with every additional serving of red meat they eat daily.

On the other hand, replacing red meat with nuts and legumes reduced risk of early brain aging, results show.

“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,” senior researcher Dr. Daniel Wang with Brigham and Women’s Hospital, an assistant professor of nutrition at the Harvard T.H. Chan School of Public Health, said in a news release from the school.

“We hope our results encourage greater consideration of the connection between diet and brain health,” Wang said.

For the study, researchers analyzed data on nearly 134,000 nurses and health professionals participating in long-term research projects tracking their health and lifestyles.

Results showed that for every additional serving of red meat, people aged about 1.6 years in cognitive ability and verbal memory.

However, replacing one serving of meat each day with nuts or legumes lowered risk of dementia by 19% and cognitive decline by 21%, researchers found.

Swapping meat for nuts or legumes also slowed brain aging by about 1.4 years, the study says.

Red meat might harm brain health by influencing unhealthy gut bacteria, researchers speculated.

One byproduct of the breakdown of red meat by gut bacteria, trimethylamine N-oxide, could harm brain health by promoting amyloid beta plaques and tau tangles -- toxic protein hallmarks of Alzheimer’s disease.

The saturated fat and salt in red meat also might have an impact on the health of brain cells, researchers added.

“Large, long-term cohort studies are essential for investigating conditions like dementia, which can develop over decades,” Wang concluded. “We are continuing to piece together this story to understand the mechanisms causing dementia and cognitive decline.”