Processed Red Meat Raises the Risk of Dementia, Study Says

It’s not news that processed red meats such as bacon, sausage, hot dogs, jerky and cold cuts have a bad health rap. Studies have tied them to the risk of obesity, heart disease, stomach cancer and colorectal cancer. Some researchers suspect that processed red meat can affect cognitive health, even though study results have been inconsistent.

A recent study is pointing to another problem with processed red meat consumption: Eating hot dogs and sliced lunch meat may increase your risk for dementia, according to research presented at the 2024 Alzheimer's Association International Conference in Philadelphia and online. 
 

Processed Red Meat and Dementia

Researchers working for the Channing Division of Network Medicine at Brigham and Women’s Hospital (Boston, MA) looked for a possible connection between processed red meat and decreased cognition by following more than 130,000 participants in the Nurses’ Health Study and Health Professionals Follow-Up Study for 43 years.

Every two to four years, researchers surveyed participants’ diets to track food frequency, such as how many servings of processed red meat they consumed. A serving of processed red meat is considered two slices of bacon, a hot dog, two links of sausage or kielbasa and one salami or bologna sandwich. During the study, 11,173 participants were diagnosed with dementia. After assessing the data, researchers found: 

• Eating one-fourth of a serving or more of processed red meat each day raised the risk of developing dementia by 14 percent compared to participants who ate less than a tenth of a daily serving.
• Swapping one serving of processed red meat with one serving of nuts and legumes each day lowered the risk of developing dementia by 20 percent.  

When researchers went deeper with 17,500 of the participants, they found an additional serving of processed red meat was linked to a hastening of cognitive aging by:

• 1.61 years, primarily in the areas of overall cognitive function, language skills, executive function and cognitive processing.
• 1.69 years primarily in the areas of verbal memory, i.e., recalling and understanding words and sentences.

“Processed red meat has been associated with health issues for years,” says Dr. Andrea Klemes, chief medical officer, MDVIP. “The problem lies in how these meats are cooked and preserved.”

Why are processed red meats unhealthy?

Processed red meats are convenient, affordable and a dietary staple for many Americans. In fact, food manufacturers estimate that Americans consume 800 million pounds of bologna, more than two billion pounds of bacon, 20 billion hot dogs and more than 250 million pounds of pepperoni every year. However, these meats have ties to health issues such as dementia, heart disease, type 2 diabetes and cancer because of the way they’re preserved.

• Preserving meat prolongs shelf life, adds flavor and improves taste and color. There are two methods:   
  Smoking. Manufacturers cook the meat at a very high temperature. This triggers the formation of unhealthy chemicals, such as heterocyclic amines, polycyclic amines, acrylamide and acrolein. It also causes the pigment in hemoglobin – the protein inside red blood cells that carries oxygen around the body -- to break down, forming N-nitroso, a compound that can damage DNA in cells. Furthermore, nitrates and nitrites are often added to help prolong shelf life, but nitrosamines can form when the meat is exposed to high heat.
• Curing. Food companies add nitrite and sodium nitrite (salt) to meat to improve taste, create a pinkish color, reduce moisture from meat and slow bacterial growth.      

Researchers think the harmful nitrites/nitrates can harm the brain. Cured meats typically have a high salt content, which can elevate blood pressure and damage blood vessels that deliver oxygen and nutrients to the brain. Studies have linked high blood pressure with strokes and brain shrinkage. It’s also possible that high blood pressure plays a role in the development of brain plaques and tangles involved in Alzheimer’s disease.

Besides brain health, eating too much processed meat can affect your heart health. These meats are high in saturated fat, which can increase your bad cholesterol levels, raising your risk for a heart attack or stroke. Unhealthy blood fat levels also raise the risk for insulin resistance, a precursor to type 2 diabetes, which is another risk factor for heart disease.

Processed red meats also have a link to cancer. The chemicals in smoked meat can damage DNA, the root cause of cancer. A high heme intake has been linked to an increased risk of colorectal, pancreatic and lung cancer. Nitrosamines and excessive dietary salt both contribute to stomach cancer.

“The study results did not find an association between meats that weren’t processed and dementia, which doesn’t surprise me,” says Klemes. “Unprocessed meats, particularly lean meats, along with other components of the Mediterranean diet, such as nuts, seeds, legumes, fruits, vegetables, healthy fats, whole grains and less processed dairy have brain health benefits.”

Tips for Controlling Sodium, Sodium Nitrites and Nitrates and Sodium in Your Diet

If you can’t do without your bacon and eggs at breakfast, you might be able to find a nitrate-free bacon that’s organic or from a local source like a farmer’s market. Make sure you cook the bacon at a lower heat and for a longer time without burning it. You can also replace bacon with grilled mushrooms or eggplant because of their savory flavor. Some stores even carry mushroom bacon and/or eggplant bacon. Of course, if you’re looking for a protein substitute, consider cheese.

For lunch, swap your deli meat sandwiches with canned tuna or salmon. Skinless barbecue chicken also might work. If you snack on processed meats like jerky, try cheese with healthy crackers, vegetables with a healthy yogurt dip or humus with pita bread.

Read food labels. Prepackaged food items should not have more than 500 mg of sodium per serving. Avoid foods that list sodium nitrate E251, sodium nitrite E250 or potassium nitrite E249. Be careful if you see the terms “uncured” or “no nitrites added” on labels. These meats aren’t necessarily healthier. They may have used another method of preserving, such as celery powder and still be high in nitrites and nitrates.

“Your best bet is unprocessed meats like fresh chicken, turkey, beef, pork and fish,” Klemes says. “Before you make changes to your diet, talk to your doctor.”

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