Eating processed red meat might raise risk of dementia

Skip the bacon and those holiday hot dogs: A new study finds eating processed red meats raises your odds for dementia.

Overall, just two servings per week of processed red meat was linked to a 14% rise in dementia risk, compared to folks who ate less than three servings per month.

The finding made sense to Heather Snyder , vice president of medical and scientific relations the Alzheimer's Association , given what experts know about diet and the brain.

"Prevention of Alzheimer's disease and all other dementia is a major focus, and the Alzheimer's Association has long encouraged eating a healthier diet -- including foods that are less processed -- because they've been associated with [a lowered] risk of cognitive decline," Snyder said in an association news release. "This large, long-term study provides a specific example of one way to eat healthier."

The findings were presented Wednesday at the Alzheimer's Association International Conference in Philadelphia.

The study was led by Yuhan Li, now a research assistant in the Channing Division of Network Medicine at Brigham and Women's Hospital in Boston. She conducted the study while a graduate student at the Harvard T.H. Chan School of Public Health.

Li's team pored over 43 years' worth of data from 130,000 people in the long-running Nurses' Health Study and Health Professionals Follow-Up Study. The researchers specifically looked at associations between red meat intake and dementia.

Every two to four years, participants were quizzed on how much and how often they ate a variety of foods, including processed red meats. A serving from that category could include bacon (two slices), hot dog (one), sausage or kielbasa (2 ounces or two small links), salami, bologna or other processed meat sandwiches.

People were also asked about their intake of servings of nuts and legumes, including peanut butter (1 tablespoon), peanuts, walnuts or other nuts (1 ounce), soy milk (8-ounce glass), string beans, beans or lentils, peas or lima beans (1/2 cup), or tofu or soy protein.

Overall, 11,173 cases of dementia emerged over the study period.

The main finding: People who said they ate a quarter-serving or more of any form of processed red meat per day had a 14% higher risk of developing dementia than those who ate less than 1/10 of a serving daily.

The study was only designed to reveal associations and could not prove cause-and-effect.

Li's team also looked at the "cognitive aging" of a subset of nearly 17,500 study participants.

They found that each extra serving of processed red meat eaten per day was tied to about 1.6 years of cognitive aging for "global cognition," which includes language, executive function and mental processing. That extra daily serving was also linked to almost 1.7 years of cognitive aging for verbal memory -- the ability to recall and understand words and sentences, Li's team reported.

There are dietary changes that can help stop that decline, however.

The study found that when folks replaced the daily serving of processed red meat with nuts and/or legumes, people got a 20% lower risk of developing dementia and 1.37 fewer years of cognitive aging in global cognition.

"Study results have been mixed on whether there is a relationship between cognitive decline and meat consumption in general, so we took a closer look at how eating different amounts of both processed and unprocessed meat affects cognitive risk and function," Li said. "By studying people over a long period of time, we found that eating processed red meat could be a significant risk factor for dementia. Dietary guidelines could include recommendations limiting it to promote brain health."

She noted that processed red meat may be bad for the brain "because it has high levels of harmful substances such as nitrites [preservatives] and sodium."

And it's not just the brain that's at risk.

"Processed red meat has also been shown to raise the risk of cancer, heart disease and diabetes," Li noted.

The study also looked at unprocessed red meat -- foods such as hamburgers, steaks or pork chops. It found no significant association between that type of meat and dementia risk.

Because these findings were presented at a medical meeting, they should be considered preliminary until published in a peer-reviewed journal.

More information

Find out more about your diet and brain health at the National Institute on Aging.

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