Cut your risk of dementia by 20% with this dietary change

Dementia risk rose by 14 per cent when people ate about one ounce of processed red meat a day — the equivalent of slightly less than two three-ounce servings a week — compared with people who only ate about three servings a month, a preliminary new study found.

The risk for dementia dropped by 20 per cent, however, for people who replaced that small daily serving of processed red meat with a daily serving of nuts and legumes.

Processed red meats such as bacon, sausage, hot dogs and deli meats often contain higher levels of sodium, nitrates and saturated fat. Eating higher amounts of these meats has been strongly linked to the development of colon and other cancers, type 2 diabetes, and heart disease and stroke, studies have shown.

“There is much we can do to reduce the risks of dementia, starting with actions that are well known to reduce risks of cardiovascular disease,” said Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health in Boston.

“There are still aspects of this to understand in more detail,” Willett said in an email. “For example it seems that some foods may be particularly important to include and we would like to understand the specific active ingredients, but we don’t need to wait for all the details to take action.”

The study was observational and can only show an association and not necessarily cause and effect, said Dr. David Katz, a specialist in preventive and lifestyle medicine who was not involved in the study.

“However, the associations are very likely to be causal, because the principal risk factors for Alzheimer’s and cognitive decline are the risk factors for cardiovascular disease, with which processed meat intake is strongly linked,” he said in an email. Katz is the founder of the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine.

An abstract of the study, which is under review for publication, was presented Wednesday at the 2024 Alzheimer’s Association International Conference in Philadelphia.

Every two to four years for over three decades, researchers captured dietary data from more than 130,000 participants in the Nurses’ Health Study, one of the largest investigations into the risk factors for major chronic diseases in women, and the complimentary Health Professionals Follow-Up Study, which investigated the same risk factors in men.

The men and women were asked how often they ate a serving of processed red meat, which could be two slices of bacon, one hot dog, two small links of sausage or kielbasa, and salami, bologna or other processed meat sandwiches.

The study participants were also asked how often they ate nuts and legumes, such as one tablespoon of peanut butter; one ounce of peanuts, walnuts or other nuts; an eight-ounce glass of soy milk; a half cup of string beans, lentils, beans, peas or lima beans; or a typical three-ounce serving of tofu or soy protein.

“Those are anti-inflammatory foods, so you can imagine they have a lot of benefits in addition to reducing the processed meats with toxins, nitrates and sodium which are not good for you,” said Dr. Maria Carrillo, chief science officer of the Alzheimer’s Association, who was not involved in the study.

In addition to the 14 per cent cognitive decline associated with approximately two servings a week of processed red meat, the study found an increased risk connected to each additional serving.

Each additional daily serving added an extra 1.61 years of cognitive aging for global cognition and an extra 1.69 years of cognitive aging in verbal memory, according to the study.

“Global cognition provides a broad overview of cognitive function. It can help to capture the overall impact of dietary and lifestyle factors on cognitive health,” said lead study author Yuhan Li, a research assistant in the Channing Division of Network Medicine at Brigham and Women’s Hospital in Boston, in an email.

“Verbal memory refers to the memory for verbally presented information. It is an important predictor of Alzheimer’s disease,” said Li, who conducted the study while a graduate student at the Harvard T.H. Chan School of Public Health.

Simply switching animal-based products for plant-based products doesn’t automatically result in a healthy diet. As the study illustrates, the outcome may depend on the types of foods you eat instead.

Rather than focusing on the benefits and negatives of specific heart-healthy foods, try to focus on an overall pattern of eating, said Christopher Gardner, a research professor of medicine at the Stanford Prevention Research Center in California who directs its Nutrition Studies Research Group. He was not involved with the study.

“When it was a single heart-healthy nutrient, you could just inject that nutrient into food and claim it’s healthy food, which it wasn’t,” Gardner told CNN in a previous interview.

“Or if there’s a superfood like chia seeds, you could take a really unhealthy food and sprinkle chia seeds on it and say, ‘Ah, I’m now protected.’ No, it needs to be part of an overall healthy pattern of foods.”

Award-winning food plans such as the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) are more of a lifestyle than a so-called “diet,” experts say. Both focus on simple, plant-based cooking, with the majority of each meal focused on fruits and vegetables, whole grains, beans, and nuts and seeds.

Red meat intake is limited. Instead, the diets emphasize eating healthy, oily fish, which are packed with omega-3 fatty acids that are good for the brain, along with lean meats such as poultry and pork loin.

An easy way to start a reduced-meat diet, according to experts, is to cook one meal each week based on beans, whole grains and vegetables, using herbs and spices to add punch. When one night a week is a breeze, add two, and build your meat-free meals from there.

When you do incorporate meat, use small pieces of chicken or slices of lean meat to flavor a veggie-based meal, such as a stir-fry.

Another easy step, experts say, is to replace refined grains with whole grains. Choose whole-wheat bread and pasta and replace white rice with brown or wild rice.