People’s love of processed meat might come back to bite them in the long run, new research from the UK suggests. The study found a link between greater consumption of processed meat and higher rates of Alzheimer’s disease and other forms of dementia. At the same time, it also found a possible link between eating unprocessed meats and a lower risk of dementia.
Processed meats such as bacon, jerky, and hot dogs don’t exactly have a reputation for being healthy in the first place. Other research has suggested that diets high in these foods are linked to chronic conditions such as type 2 diabetes, cardiovascular disease, and some types of cancer. Some studies have even pointed to a link between processed meats and the increased risk of neuropsychiatric symptoms, such as episodes of bipolar depression.
There’s been mixed evidence that a diet high in meat could raise a person’s risk of dementia in their later years. But according to the authors of this new study, published Monday in The American Journal of Clinical Nutrition, there’s been less work to separate out the possible dementia risk from different types of meats (processed versus not) and whether genetics may play a role in that risk.
The study relied on population data from the UK Biobank, an ongoing research project that’s collected health and genetic information from around a half million residents, ages 40 to 69, between 2006 and 2010. As part of the project, volunteers filled out a questionnaire about their diet at the start of their enrollment and in periodic online surveys for up to 16 months after. Because of the UK’s nationalized health system, the researchers were then able to track the health outcomes of these participants, including whether they developed or died from dementia.
About 2,900 cases of dementia were diagnosed in the entire group, during an average eight-year follow-up period. And when the researchers tried to account for people’s diets, they found a clear association between processed meat and the risk of dementia, but they didn’t see the correlation when it came to other types of meat.
For example, the associated risk of dementia rose by 44% for every 25 grams of processed meat eaten daily. But there was no significant link found between dementia risk and total meat consumption or between dementia risk and a person’s daily intake of chicken. Meanwhile, the associated risk of dementia actually declined slightly for those who regularly ate unprocessed red meat (cooked beef, veal, pork, etc.). The risk of dementia increased for those who carried the APOE ε4 genetic variation, as expected, but this risk wasn’t affected by meat consumption.
“Our findings suggest that consumption of processed meat may increase risk of incident dementia, and unprocessed red meat intake may be associated with lower risks,” the authors wrote.
Nutritional studies like this one have their limitations, of course. For instance, they can’t show a direct cause-and-effect relationship between any two things, only a correlation. Studying people’s diets is hard in general, since we aren’t the greatest at remembering what and how much of any given food we eat regularly. And of course, a person’s diet at 40 or 50 might still change significantly between then and the time of their dementia diagnosis years or decades later.
Any single study shouldn’t be seen as the final verdict on a topic. More research will have to be done to tease out the potential effects of a diet high in processed meats on our dementia risk and how these diets may be causing it. That said, as mentioned earlier, this wouldn’t be the first study tying processed meats to worsening health. So while the specifics still need to be worked on, it’s likely in many of our best interests to cut down on bacon or sausage anyway.
“Worldwide, the prevalence of dementia is increasing and diet as a modifiable factor could play a role,” said lead author Huifeng Zhang, a PhD student from the University of Leeds’ School of Food Science and Nutrition, in a statement released by the UK-based university. “Our research adds to the growing body of evidence linking processed meat consumption, to increased risk of a range of non-transmissible diseases.”