A review of studies, published in 2023, found that people who ate large quantities of ultra-processed foods of all kinds, not just processed meats, had a 44% higher risk of dementia. Gut health can be negatively affected by ultra-processed foods such as chips, carbonated beverages, breakfast cereals and ready meals. Unfortunately, much of what most of us eat is processed, from canned vegetables to bread and milk. However, this review also noted that eating moderate amounts of ultra-processed foods was not associated with a higher risk of dementia.
Mounting evidence supports the idea that healthy diets, such as the MIND or Mediterranean-style diet, which are low in processed foods and high in vegetables, olive oil and omega 3s, improve brain health. Diet is a modifiable lifestyle factor, which means we can make healthier food choices to support our brain health.
Research suggests that highly processed foods with lots of calories, salt, fat and added sugars, such as sugary sodas, grocery store birthday cake, fast food burgers and fries, may cause older adults’ cognitive abilities to decline more rapidly. Consumption of red and processed meat can increase risk of heart disease, diabetes, and cancer, and these diseases share risk factors with dementia, including the most common type, Alzheimer’s disease.
A large U.S.-based study investigated the association between dementia risk and different foods in more than 133,000 healthcare professionals who did not have dementia when the study started. These people were tracked for more than four decades, and in that time, about 11,000 developed dementia.
The researchers learned that eating processed red meat (such as bacon, hot dogs, salami, and sausages) was associated with a 16% higher risk of dementia and a fast rate of cognitive aging. A serving is usually around 3 ounces, which would be either two slices of bacon, 1.5 slices of bologna or one hot dog. Eating roughly two servings of processed red meat per week raised the risk by nearly 15% compared with those who ate less than about three servings per month.
People who substituted processed red meat protein with the protein found in nuts, tofu, or beans reduced their dementia risk by 19%, and reduced their rate of cognitive aging.
Because red or processed meat has a lot of saturated fat and cholesterol (bad fats), it can result in fatty deposits building up in the blood vessels, which can contribute to heart disease. The high salt content of processed meats can contribute to high blood pressure, and when combined with a sedentary lifestyle might lead to inflammation of blood vessels. These factors are all associated with Alzheimer’s disease. In contrast, good fats found in fatty fish, olive oil, nuts, and avocados may protect against dementia and cognitive decline.
One study, by Gonçalves in Brazil, tracked 10,775 people with an average age of 50 for up to a decade. The researchers found that people who ate a lot of ultra-processed food were more likely to experience declining decision-making abilities and declining ability to learn, remember and focus on things overall as they aged.