Processed red meat intake ups dementia risk

In a study that tracked over 100,000 individuals for over 40 years, the risk of dementia is higher among those who consumed about two servings of processed red meat per week as opposed to those who consumed less.

“Higher intake of red meat, particularly processed red meat, was associated with a higher risk of developing dementia and worse cognition,” noted the investigators, led by Yuhan Li, research assistant from the Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, US.

Compared with individuals who had low (<0.10 serving/day) processed red meat intake, those who had high (≥0.25 serving/day) consumption had a 14-percent higher risk of dementia and a 13-percent higher risk of subjective cognitive decline. [AAIC 2024, proposal ID 88556]

There were also significant associations between higher processed red meat intake and accelerated ageing in global cognition (1.61 years per one serving/day increment, 95 percent confidence interval [CI], 0.20–3.03) and verbal memory (1.69 years per one serving/day increment, 95 percent CI, 0.13–3.25; p_{linear trend}=0.03 for both).

On substitution analyses, replacing one daily serving of processed red meat with nuts and legumes was tied to a 20-percent lower risk of dementia (hazard ratio, 0.80, 95 percent CI, 0.75–0.86), 1.37 fewer years of cognitive ageing (95 percent CI, -2.49 to -0.25), and a lower likelihood of subjective cognitive decline (odds ratio, 0.80, 95 percent CI, 0.69–0.92).

Limit red meat intake for brain health

The risk of dementia was evaluated using data from participants in the Nurses’ Health Study (NHS; n=87,424) and Health Professionals Follow-Up Study (n=46,347). A total of 11,173 dementia cases were identified. Diet was assessed every 2–4 years based on participants’ answers to a validated semi-quantitative food-frequency questionnaire (FFQ).

In the FFQ, participants were asked how often they ate a serving of processed red meat, including bacon (two slices), hotdog (one), sausage or kielbasa (2 ounces or two small links), salami, bologna, or other processed meat sandwiches, as well as 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.

Objective cognitive function was evaluated in a subset of NHS participants (n=17,458) using the Telephone Interview for Cognitive Status and five other cognitive tests. The researchers longitudinally gathered data on subjective cognitive decline from NHS (n=33,908) and Health Professionals Follow-Up Study (n=10,058) participants.

“[W]e took a closer look at how eating different amounts of both processed and unprocessed meat affects cognitive risk and function,” noted Li in the AAIC press release. “By studying people over a long period of time, we found that eating processed red meat could be a significant risk factor for dementia … [Processed red meat] may affect the brain because it has high levels of harmful substances such as nitrites (preservatives) and sodium.”

“Dementia ranks as the seventh leading cause of death globally but has no effective cure. Diet is a modifiable factor that can help to develop dietary guidelines … Reducing red meat consumption could be included in dietary guidelines to promote cognitive health,” Li and colleagues concluded.

“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 have been associated with lower risk of cognitive decline,” noted Alzheimer’s Association vice president of medical and scientific relations Dr Heather Snyder in the AAIC news release. “This large, long-term study provides a specific example of one way to eat healthier.”