A diet rich in ultra high-processed foods is associated with an increased risk for all-cause dementia and Alzheimer disease (AD) dementia, according to study findings published in the journal Alzheimer’s & Dementia.
With the prevalence of AD estimated to double worldwide in 20 years, preventative strategies aimed to reduce the progression of disease are crucial in lessening disease burden. Alteration of dietary habits, specifically the limitation of ultra-processed foods is postulated to decrease disease burden, by avoidance of their established neuroinflammatory effects.
For the study, researchers sought to assess the association of consumption of ultra-processed foods and the risk of developing all-cause dementia. To evaluate patients and their spouses, aged 18 and older, the researchers used data from the second generation Framingham Heart Study (FHS; ClinicalTrials.gov Identifier: NCT00005121), termed the Framingham Offspring Cohort (FOS), which is a large, population-based cohort study in which participants underwent standardized physician examinations and laboratory tests.
Individuals with inefficient or excess energy intake, defined as <600– >3999 kcal for women or >4199 kcal for men, as well as missing >13 items from the 131-item Food Frequency questionnaire (FFQ) were excluded from the study.
All food items in the FFQ were numbered 1-5 according the NOVA classification system; the increased numbering is associated with higher level of food processing. Dementia diagnosis was based on the international classification of diseases (ICD) and Statistical Manual of Mental Disorders, fourth edition. Criteria from the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association (NINCDS-ADRDA) was used for the diagnosis of AD.
The final analysis consisted of 1354 men and 155 women with a mean age at baseline of 52.4 years. Consumption of ultra-processed foods was organized into quartiles (energy-adjusted ultra-processed food consumption), and the range of adjusted ultra-processed food consumption was <5.2 servings/day in the first quartile, to ≥9.1 servings/day in the fourth quartile. Participants in the fourth quartile were more likely to be men, have a higher body mass index (BMI), prone to be more sedentary, consume more caffeine, and processed meat, fried food, and added sugar.
During a mean follow-up of 14.4 years, the researchers found a total of 306 dementia cases; a higher incidence of dementia was found in those in the highest quartile of ultra-processed food intake, when compared with the lowest quartile (13.8% vs 6.7%). Across all energy-adjusted ultra-processed food consumption categories, no significant difference in dementia subtypes were noted.
Multivariate adjustment models using cox regression analysis also found the highest quartile of ultra-processed food consumption to have a higher risk for all-cause dementia (HR, 1.61; 95% CI 1.09–2.16), as well as a higher risk for AD dementia (HR, 1.75; 95% CI 1.04–2.71). Subgroup analysis found no significant factors when adjusting for age, sex, education, BMI, and smoking status (P <0.05).
As an observational study, confounding was cited as a potential limitation, due to unmeasured risk factors for dementia. Additionally, measurement error is possible, as the FFQ was solely used to assess dietary intake.
The researchers wrote, “high consumption of UPF [ultra-processed foods] is associated with increased risks of all-cause dementia and AD dementia, independent of age and sex, as well as multiple demographic factors.” “If causality is established, limiting trends of UPF intake around the globe could contribute to reducing the burden of dementia,” they concluded.
Wang K, Tang W, Hao X, Zhao J. Ultra-processed food consumption and risk of dementia and Alzheimer’s disease: long-term results from the Framingham Offspring Study. Alzheimers Dement. Published online July 3, 2023. doi:10.1002/alz.13351