People with dementia have difficulties with memory, attention, thinking, and reasoning that interfere with daily activities. These cognitive difficulties are not part of the typical aging process.
The World Health Organization (WHO) reports that there are around 50 million cases of dementia worldwide, with around 10 million new cases diagnosed each year. Alzheimer’s disease is the most common cause of dementia, accounting for 60-70% of cases. About 5-10% of cases are associated with impaired blood circulation in the brain, for example, as a result of a stroke. Both genetic and environmental factors, including diet and lifestyle, are known to influence the development and progression of dementia.
Previous research has already established a link between overall meat consumption and the risk of developing the disease. However, a new study by scientists at the University of Leeds, UK, suggests there is a link between eating processed meat in particular and an increased risk of developing dementia. Processed meats include products such as sausages, bacon, salami, and corned beef.
That said, research also indicates that red meat may have a protective effect against dementia. The study is published in The American Journal of Clinical Nutrition.
Diet, genetics and lifestyle
The scientists analyzed data from the UK Biobank, a database containing genetic and health information from around half a million British volunteers aged 40 to 69. When recruited, each participant completed a questionnaire about their diet and completed 24-hour dietary assessments. The researchers were thus able to estimate the total amount of meat each participant ate on a regular basis and the amount of each type of meat they ate. The database also allowed them to identify participants who carried the APOE ε4 genetic variant, which is known to increase the risk of dementia.
They then used hospital and mortality records to identify subsequent cases of all-cause dementia, Alzheimer’s disease and vascular dementia during the approximately 8-year follow-up period. Of the 493,888 participants, 2,896 suffered from dementia from all causes. Among them, 1,006 cases of Alzheimer’s disease and 490 cases of vascular dementia.
Each additional serving of processed meat consumed per day increases the risk by 44%
To estimate the role of meat consumption, the researchers had to take into account a wide range of other factors known to affect a person’s likelihood of having dementia. These include age, gender, ethnicity, education and socioeconomic status. In addition, the researchers took into account lifestyle factors, such as smoking, physical activity, and consumption of fruits and vegetables, fish, tea, coffee, and alcohol.
After these adjustments, they found that each additional 25g serving of processed meat consumed per day was associated with a 44% increased risk of dementia from all causes. This consumption was also associated with a 52% increase in the risk of Alzheimer’s disease.
In contrast, each additional 50g serving of unprocessed meat consumed per day was linked to a 19% reduction in the risk of all-cause dementia and a 30% reduction in the risk of Alzheimer’s disease. The results for unprocessed poultry and total meat consumption were not statistically significant. As expected, the researchers noted that having the APOE ε4 allele increased the risk of dementia by 3 to 6 times. However, it did not significantly affect the observed associations between diet and dementia.
Processed meat and the risk of other diseases
There is a lot of evidence linking the consumption of processed meat to cancer. In 2015, the WHO even went so far as to define it as a carcinogen.
“Around the world, the prevalence of dementia is increasing, and diet, as a modifiable factor, may play a role,” says Huifeng Zhang, a doctoral student at the School of Food and Nutrition Sciences of the University of Leeds, who was the principal investigator of the new study. “Our research adds to the growing body of evidence linking processed meat consumption to an increased risk of a range of non-communicable diseases,” she adds.
Sources
https://pubmed.ncbi.nlm.nih.gov/30883348/
Meat consumption and risk of incident dementia: cohort study of 493,888 UK Biobank participants.
IARC Monographs evaluate consumption of red meat and processed meat.
