While red meat is a rich source of protein, iron and other nutrients, a recent study linked it to an increased risk of dementia — but some doctors are casting doubt on the claim.

Researchers from the Harvard T.H. Chan School of Public Health and Mass General Brigham found that daily consumption of certain amounts of processed red meats increased dementia risk by 13%, according to a press release.

It was also tied to a 14% higher risk of developing subjective cognitive decline and faster brain aging.

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“The findings did not really surprise us,” lead study author Yuhan Li, a researcher from Harvard T.H. Chan School of Public Health in Boston, told Fox News Digital.

“The results are generally in line with our hypothesis, showing that a higher intake of red meat, particularly processed red meat, is associated with an increased risk of developing dementia and worse cognition.”

The increased risk was seen in people who ate at least one-quarter of a serving of unprocessed meats per day, according to the research article. This equates to around one hot dog, two slices of bacon, or one and a half slices of bologna.

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The researchers also suggested that replacing one serving of processed red meat per day with a serving of nuts and legumes could reduce dementia risk by 19% — and that replacing it with fish could reduce the risk by 28%.

The study included 133,771 individuals, 11,173 of whom received a dementia diagnosis over a four-decade span. The data came from the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS), which tracked participants’ dietary choices and health status.

Funded by the National Institutes of Health, the study was published on Jan. 15 in the journal Neurology.

The findings were first presented at the Alzheimer’s Association International Conference (AAIC) earlier in 2024.

Experts react to the findings

“There are many reasons to believe that too much red meat is linked to dementia,” Dr. Marc Siegel, clinical professor of medicine at NYU Langone Health and Fox News senior medical analyst, told Fox News Digital.

“In the case of processed meat like bacon and ham, the chemicals added may also lead to dementia via inflammation and neuroinflammation,” added Siegel, who was not involved in the new research.

The doctor also warned of red meat potentially leading to weight gain and obesity, which can cause inflammation and in turn raise the risk of dementia. 

“Red meat may also lead to heart disease, which increases dementia risk,” Siegel noted.

Theresa Gentile, a registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics in New York, noted that previous research has found an association between red meat — especially processed red meat — and an increased risk of type 2 diabetes and cardiovascular disease, which are both related to impaired cognitive health. 

“There isn’t a single food or ingredient that … has been shown to cause, increase risk, prevent, treat or cure Alzheimer’s or other dementias.”

“This was a large study conducted over a long period of time and was adjusted for confounding factors and still found that, in three different groups, eating more processed red meat was associated with cognitive decline than eating less,” Gentile, who did not work on the study, told Fox News Digital. 

Some experts suggested that the risk is linked more to ultraprocessed foods in general rather than specific meats.

Heather M. Snyder, Ph.D., senior vice president of medical and scientific relations at the Alzheimer’s Association in Chicago, pointed out that a number of studies have suggested that diets with more ultraprocessed foods are bad for brain health. 

“For example, a report at the AAIC 2022 found that people who eat large amounts of ultraprocessed foods have a faster decline in cognition,” Snyder, who was not involved in the new study, told Fox News Digital.

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“More than 20% of daily intake of ultraprocessed foods led to a 28% faster decline in global cognitive scores, including memory and verbal fluency.”

It is “unlikely” that one food will have a “significant beneficial or detrimental effect on a disease as complex as Alzheimer’s,” according to Snyder.

“There isn’t a single food or ingredient that, through rigorous scientific research, has been shown to cause, increase risk, prevent, treat or cure Alzheimer’s or other dementias,” she stated.

Potential study limitations

Siegel noted that the study was observational, which means that “no strict conclusions can be drawn.”

“We still need double-blinded, randomized trials to draw more definite conclusions,” he said.

Lead study author Yuhan also acknowledged the potential limitations.

“The Nurses’ Health Study enrolled female registered nurses, and the Health Professionals Follow-Up Study enrolled U.S. male health professionals,” she told Fox News Digital.

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“These participants tend to have higher educational attainment and income levels, and therefore, the study’s generalizability may be limited. In addition, because this study is an observational study, residual confounding remains a possibility.”

Dr. Ken Berry, a family physician and diabetes specialist in Tennessee, was not involved in the study but shared his thoughts on “healthy user bias” potentially skewing the results.

“The people who are eating the least amount of processed meat and the least amount of red meat in these studies — they were also exercising every day,” he said in a video posted on his YouTube channel last week.

“They absolutely did not smoke. They did not drink to excess. They were trying their best to live a healthy life.”

“We still need double-blinded, randomized trials to draw more definite conclusions.”

Research has shown that exercising regularly and eating whole, unprocessed foods can decrease the risk of dementia, Berry noted.

“I don’t think any nutrition expert would argue with that,” he said, but added that there is “no evidence whatsoever” that red meat is linked to higher dementia risk.

Healthy dietary tips

Gentile recommended limiting servings of processed red meats like bacon, sausage, hot dogs and deli meats to less than a quarter of a serving per day, and to consider healthier protein alternatives like fish, nuts, legumes and chicken. 

“A balanced diet with moderation in terms of protein sources and serving size is key,” Gentile said. “If your diet is heavy in processed red meats, try swapping one of those servings out for beans, fish or chicken.”

The nutritionist also suggested including brain-boosting foods each day, like fruits, vegetables, whole grains and healthy fats.

The Alzheimer’s Association has long encouraged eating a balanced diet to help prevent Alzheimer’s disease and all other dementia types, Snyder noted.

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“That includes foods that are less processed to ensure that our bodies get the needed nutrients, because they’ve been associated with a lower risk of cognitive decline,” she told Fox News Digital. 

“As research continues, we may uncover other dietary patterns that increase or decrease our risk.”

Berry pointed out that while he is a self-described “carnivore,” he is not completely “anti-plant.”

“I’m a proponent of a proper human diet, which ranges from low-carb with vegetables and berries and nuts, to keto with a few berries and vegetables and nuts, to ‘ketovore’ with just a little veg for flavor and garnish, all the way to carnivore,” he said in his video. 

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The best diet for any individual should depend on multiple factors, he said, including their overall metabolic health, age, weight, genetics and gut microbiome.

Added Berry, “That’s the proper human diet spectrum.”