NBC News
A diet high in processed red meat is linked to an increased risk of dementia, according to a new study presented Wednesday at the Alzheimer’s Association International Conference in Philadelphia.
The findings, which have not yet been peer-reviewed, are the result of a four-decade study involving more than 130,000 adults that looked at the relationship between diet and cognition.
“This is one of the most robust studies I’ve seen on the relationship between processed meat consumption and dementia because it followed individuals for decades,” said Dr. Maria Carrillo, chief scientific officer of the Alzheimer’s Association.
Researchers found that people in the study who ate at least two servings of processed red meat (such as bacon, bologna or sausage) per week had a 14 percent higher risk of dementia, compared with those who ate fewer than three servings per month, after a 43-year follow-up period.
The study also found that each additional daily serving of processed red meat was linked to an additional 1.6 years of cognitive aging, specifically in the area affecting a person’s language ability and executive function, which includes the mental skills that control behavior.
However, it wasn’t all bad news. The study found that replacing one serving of processed red meat a day with one serving of nuts or beans was linked to a 20% lower risk of cognitive decline.
“This is really consistent with a broader body of science that tells us that diets with less fat, less sugar and more vegetables in general are best for our brain health,” said Dr. Heather Snyder, vice president of medical and scientific relations for the Alzheimer’s Association.
The study adds to a growing body of research showing that processed foods can worsen overall health.
“Processed red meat has also been shown to increase the risk of cancer, heart disease and diabetes,” said Yuhan Li, senior author of the study and an associate investigator in the Channing Division of Network Medicine at Brigham and Women’s Hospital, in a statement. “It can affect the brain because it is the leading cause of death.”
“It can affect the brain because it has high levels of harmful substances such as nitrites (preservatives) and sodium.”
Carrillo noted that unprocessed red meats — such as ground beef or steak — were not linked to the same cognitive impairments in the study.
“When unprocessed and in moderation, red meat is actually really good for you,” she said.
Dr. Uma Naidoo, a psychiatrist and director of nutritional and lifestyle psychiatry at Massachusetts General Hospital, said the size and length of the study strengthened the results. She noted, however, that the findings were observational and therefore do not prove that eating processed red meat definitively causes dementia.
Snyder also acknowledged that while the study, conducted on a group of mostly white, higher socioeconomic health care professionals, may not be representative of the U.S. population at large, it still points in the general direction of reducing processed red meat intake as a way to improve brain health.
What to eat instead of processed red meat
One of Naidoo’s key takeaways from the study was that people should eat fresh, whole foods as much as possible.
“The less processed, the better,” Naidoo said. “Good portions of vegetables and fruits provide fiber, nutrients, minerals and vitamins for the body and brain.”
Naidoo pointed to studies showing that diets with fresh, whole foods are linked to longer life expectancy and fewer health problems.
Naidoo also offered suggestions for people who don’t have regular access to fresh, whole foods. Canned fish and beans, as well as frozen vegetables, can be affordable and widely available sources of protein and other nutrients for people looking for alternatives to processed red meat. Canned beans can be drained and rinsed to reduce their sodium content, and frozen vegetables can serve as whole foods because they are flash-frozen at their optimal ripeness. Still, Naidoo recommends looking for low-sodium options for those who choose to add these foods to their diet.
Dr. Yian Gu, an associate professor of neurological sciences at Columbia University Medical Center in New York, said a healthy diet is only one part of a healthy lifestyle to prevent dementia.
“It is not only necessary to eat fresh and healthy food, but also to lead a healthy lifestyle: getting enough sleep, exercising, maintaining social contact and engaging in leisure activities. All of these contribute to improving health,” Gu said.
Carrillo agreed. “It is important to remember that these decisions, even if they seem insignificant, have long-term repercussions,” he said. “These are things we have to think about continuously, because we are living longer and we want to be as healthy as possible,” he added.
