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According to the NOVA Food Classification System, ultra-processed food (UPF) is an industrial formulation mostly comprised of substances that are extracted from foods (e.g., oils, fats, and sugar), derived from food components (e.g., hydrogenated fats), or synthesized in laboratories (e.g., food additives).¹ Soft drinks, candies, packaged bakery items, pre-prepared pasta dishes and pizzas, fish nuggets, and hot dogs are just a few examples of UPF. Across the globe, UPF has become more commonplace in the modern diet, and some reports estimate that the consumption of these foods accounts for up to 80% of the caloric intake in Westernized countries such as the United States and Canada.² Increased intake of UPF has been associated with a rise in consumed calories, added sugars, total fats, and saturated fats, as well as a reduced intake of fiber and many health-optimizing vitamins and minerals.^2,3

Excessive consumption of UPF has consistently been associated with negative health impacts from increased odds of poor sleep quality⁴ and mental health conditions⁵ to increased risks of cardiometabolic disorders,⁶ cancer,⁷ and both cardiovascular disease and all-cause mortality.⁸ How does a high intake of these highly processed foods and meals impact brain health?

To explore this relationship, an initial meta-analysis of 10 observational studies (n=867,316 adults) found that compared to a lower intake of UPF, those individuals with higher intakes of UPF had a 44% increased risk of dementias, including mild cognitive impairment and vascular dementia.⁹ Building on this evidence, a new systematic review dives deeper into the UPF/brain relationship to investigate the links between UPF consumption levels and the specific risk of developing Alzheimer’s disease.¹⁰

Ultra-Processed Food & Alzheimer’s Risk

According to its authors, the 2024 Claudino et al study is the first systematic review to investigate the association between UPF consumption and the risk of Alzheimer’s disease development.¹⁰ This review included five cohort studies (n=617,502 adults and older adults; 54.7% female; age range 37 to 73 years) that were conducted in the US, United Kingdom, or Sweden.¹⁰ Participants did not have Alzheimer’s or any form of dementia at the start of the studies and were monitored from 8-24 years. UPF consumption was the exposure while a healthy dietary pattern with minimally processed foods and lower UPF intake was the comparison. UPF was defined using the NOVA food classification system criteria.¹⁰ In addition, the included studies appear to lack racial diversity, with only one cohort study listing race/ethnicity among the participant demographics. In that cohort study (n=493,888), 94.5% of its participants identified as white.¹¹

Overall, four of the included cohort studies (n=616,900 participants) indicated a risk association between higher UPF consumption and the development of Alzheimer’s disease.¹⁰ The remaining study (n=602; monitored for 24 years) showed a risk association between higher UPF consumption and higher dementia incidence only in individuals carrying the APOE4 allele, a significant genetic risk factor for Alzheimer’s disease.^10,12 Some of the specific results from the other cohort studies included in the systematic review were as follows:

• Individuals who had higher consumption of processed meats had an increased incidence of Alzheimer’s disease, with a hazard ratio of 1.52 per additional 25g/day.¹¹ Of note, one hot dog link may weigh 40 grams or more, while a prepackaged dessert, such as a single Twinkie, weighs 38 grams.
• Increasing UPF intake by 10% showed a significant 13% increase in the risk of Alzheimer’s disease incidence.¹³
• Replacing 10% of UPF intake with an equivalent amount of unprocessed or minimally processed foods had an estimated 17% reduction in dementia risk.¹³

Many lifestyle factors may have a positive impact on the brain. As examples, studies suggest that adequate sleep,¹⁴ increasing physical activity,¹⁵ and avoiding chronic environmental toxicant exposures¹⁶ may all affect cognitive health. The 2024 Claudino et al study emphasizes the positive impact that healthy eating choices may also have on reducing Alzheimer’s disease risk and optimizing brain health. A functional medicine approach recognizes the importance of the nutrition/brain relationship, implementing personalized dietary plans that include neuroprotective foods and nutrients that may impact cognitive functioning, neuroinflammation, and brain plasticity.^17,18

Read more about the functional medicine approach to boosting brain health in the following related articles.

Related Articles

Environmental Toxicants: A Risk Factor for Neurodegenerative Diseases

Oral Dysbiosis and Alzheimer’s Disease Risk

Clearing Brain Toxins: The Role of Sleep and Glymphatic Flow

Nutrition: A Key Modulator of Cognitive Health

Slowing Neurodegeneration With Exercise

References

1. Gibney MJ. Ultra-processed foods: definitions and policy issues. Curr Dev Nutr. 2018;3(2):nzy077. doi:1093/cdn/nzy077
2. Martini D, Godos J, Bonaccio M, Vitaglione P, Grosso G. Ultra-processed foods and nutritional dietary profile: a meta-analysis of nationally representative samples. Nutrients. 2021;13(10):3390. doi:3390/nu13103390
3. Aljahdali AA, Rossato SL, Baylin A. Ultra-processed foods consumption among a USA representative sample of middle-older adults: a cross-sectional analysis. Br J Nutr. Published online January 4, 2024. doi:1017/S0007114523003033
4. Delpino FM, Figueiredo LM, Flores TR, et al. Intake of ultra-processed foods and sleep-related outcomes: a systematic review and meta-analysis. Nutrition. 2023;106:111908. doi:1016/j.nut.2022.111908
5. Lane MM, Gamage E, Travica N, et al. Ultra-processed food consumption and mental health: a systematic review and meta-analysis of observational studies. Nutrients. 2022;14(13):2568. doi:3390/nu14132568
6. Vitale M, Costabile G, Testa R, et al. Ultra-processed foods and human health: a systematic review and meta-analysis of prospective cohort studies. Adv Nutr. 2024;15(1):100121. doi:1016/j.advnut.2023.09.009
7. Chang K, Gunter MJ, Rauber F, et al. Ultra-processed food consumption, cancer risk and cancer mortality: a large-scale prospective analysis within the UK Biobank. EClinicalMedicine. 2023;56:101840. doi:1016/j.eclinm.2023.101840
8. Zhao Y, Chen W, Li J, et al. Ultra-processed food consumption and mortality: three cohort studies in the United States and United Kingdom. Am J Prev Med. 2024;66(2):315-323. doi:1016/j.amepre.2023.09.005
9. Henney AE, Gillespie CS, Alam U, Hydes TJ, Mackay CE, Cuthbertson DJ. High intake of ultra-processed food is associated with dementia in adults: a systematic review and meta-analysis of observational studies. J Neurol. 2024;271(1):198-210. doi:1007/s00415-023-12033-1
10.  Claudino PA, Bueno NB, Piloneto S, et al. Consumption of ultra-processed foods and risk for Alzheimer’s disease: a systematic review. Front Nutr. 2024;10:1288749. 2024:10:1288749. doi:3389/fnut.2023.1288749
11.  Zhang H, Greenwood DC, Risch HA, Bunce D, Hardie LJ, Cade JE. Meat consumption and risk of incident dementia: cohort study of 493,888 UK Biobank participants. Am J Clin Nutr. 2021;114(1):175-184. doi:1093/ajcn/nqab028
12.  Samuelsson J, Najar J, Wallengren O, et al. Interactions between dietary patterns and genetic factors in relation to incident dementia among 70-year-olds. Eur J Nutr. 2022;61(2):871-884. doi:1007/s00394-021-02688-9
13.  Li H, Li S, Yang H, et al. Association of ultraprocessed food consumption with risk of dementia: a prospective cohort study. Neurology. 2022;99(10):e1056-e1066. doi:1212/WNL.0000000000200871
14.  Wu TT, Zou YL, Xu KD, et al. Insomnia and multiple health outcomes: umbrella review of meta-analyses of prospective cohort studies. Public Health. 2023;215:66-74. doi:1016/j.puhe.2022.11.021
15.  Falck RS, Davis JC, Best JR, Crockett RA, Liu-Ambrose T. Impact of exercise training on physical and cognitive function among older adults: a systematic review and meta-analysis. Neurobiol Aging. 2019;79:119-130. doi:1016/j.neurobiolaging.2019.03.007
16.  Gunnarsson LG, Bodin L. Occupational exposures and neurodegenerative diseases—a systematic literature review and meta-analyses. Int J Environ Res Public Health. 2019;16(3):337. doi:3390/ijerph16030337
17.  Poulose SM, Miller MG, Scott T, Shukitt-Hale B. Nutritional factors affecting adult neurogenesis and cognitive function. Adv Nutr. 2017;8(6):804-811. doi:3945/an.117.016261
18.  Di Majo D, Cacciabaudo F, Accardi G, et al. Ketogenic and modified Mediterranean diet as a tool to counteract neuroinflammation in multiple sclerosis: nutritional suggestions. Nutrients. 2022;14(12):2384. doi:3390/nu14122384