Understanding the Association Between Consumption of Ultra-Processed Foods and Cognitive Decline

January 8, 2026 •

4 min read

According to a 2022 study in Brazil involving nearly 11,000 adults, those who consumed the most ultra-processed foods showed a 28% faster rate of global cognitive decline over an 8-year period. This research highlights the significant association between consumption of ultra-processed foods and cognitive decline, raising serious public health concerns.

Quick Summary

Higher consumption of ultra-processed foods, which are rich in unhealthy fats, sugar, and additives, is linked to a faster rate of cognitive decline and higher dementia risk. Key mechanisms involve chronic inflammation, gut-brain axis disruption, and poor nutrient intake. Reducing intake is recommended for better brain health.

Key Points

Significant Association: High intake of ultra-processed foods (UPFs) is consistently linked to an increased risk and accelerated rate of cognitive decline and dementia.
Faster Decline Rate: Studies show that consuming more than 20% of daily calories from UPFs can lead to a 28% faster rate of cognitive decline.
Inflammation and Gut Health: UPFs promote chronic inflammation and disrupt the gut microbiome, both of which negatively impact brain health.
Nutrient Displacement: The convenience of UPFs often replaces nutrient-dense whole foods, leading to a diet lacking essential vitamins, minerals, and fiber critical for brain function.
Genetic Risk Amplification: The negative effects of UPF consumption may be amplified in individuals with genetic predispositions for certain neurodegenerative conditions, such as APOE4 carriers.
Mitigating Strategies: Replacing a small percentage of UPFs with whole foods can significantly lower cognitive decline and dementia risk.

The Expanding Body of Evidence Linking UPFs to Cognitive Decline

Ultra-processed foods (UPFs) have become a dominant part of modern diets, comprising more than 50% of the daily caloric intake in many developed countries. Defined by the NOVA classification system, UPFs are industrial formulations often containing food substances (like oils, fats, sugars, and starches) and additives (including artificial flavors, colorings, and emulsifiers) with little to no whole food content. Unlike processed foods such as canned vegetables or cheese, UPFs undergo extensive and complex processing. A growing number of large-scale, long-term studies have now solidified the link between high UPF consumption and negative cognitive outcomes.

Scientific Studies Highlight the Risk

Several significant observational studies have demonstrated a clear correlation between UPF intake and accelerated cognitive decline. For example, the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) followed participants aged 35 to 74 over several years and found that higher UPF consumption was associated with a faster rate of decline in global cognition and executive function. The study found that individuals with UPF intake exceeding 19.9% of their daily calories experienced significantly accelerated cognitive decline.

Another study, published in Neurology, looked at over 72,000 adults over the age of 55 and found a 25% higher risk for dementia in those eating the highest amounts of UPFs compared to those who ate the least. The researchers in that study estimated that replacing just 10% of UPF intake with unprocessed or minimally processed foods could lower dementia risk by 19%. A meta-analysis of observational studies, published in Practical Neurology, further confirmed this association, finding high UPF intake was significantly associated with an increased risk of dementia.

Biological Mechanisms at Play

The association between high UPF consumption and cognitive decline is not simply a correlation but is explained by several key biological mechanisms. These include:

Chronic Inflammation: The high content of refined sugars, unhealthy fats, and additives in UPFs can trigger systemic inflammation throughout the body, including the brain. Chronic low-grade inflammation is a well-known risk factor for neurodegenerative diseases.
Gut-Brain Axis Disruption: UPFs often lack the fiber and nutrients necessary to support a healthy gut microbiome. An imbalance in gut bacteria can disrupt the gut-brain axis, a crucial communication pathway between the digestive system and the central nervous system. This disruption can influence neurotransmitter production and fuel neuroinflammation.
Blood Sugar Fluctuation: The high glycemic index of many UPFs causes rapid spikes and crashes in blood glucose. Frequent fluctuations can contribute to metabolic problems, increasing the risk of conditions like Type 2 diabetes, which is a known risk factor for cognitive decline.
Neurotoxic Additives: Some additives and nanoparticles commonly found in UPFs, such as certain emulsifiers and sweeteners, have been shown to potentially cross the blood-brain barrier. In animal studies, these substances have been linked to memory and learning impairments.

Comparison of Food Types and Their Impact on Cognitive Health

To better understand the contrast, comparing ultra-processed foods with whole or minimally processed foods illustrates why the latter is superior for brain health.


Feature	Ultra-Processed Foods (UPFs)	Whole/Minimally Processed Foods
Nutrient Density	Low in essential vitamins, minerals, and fiber. High in sugar, salt, and unhealthy fats.	High in essential nutrients, fiber, antioxidants, and healthy fats. Supports optimal brain function.
Inflammatory Impact	Promote chronic inflammation, linked to neurodegeneration.	Contain anti-inflammatory compounds that protect brain cells from damage.
Effect on Gut Microbiome	Can disrupt gut bacteria balance, negatively impacting the gut-brain axis.	Support a healthy, diverse gut microbiome vital for brain health.
Metabolic Effects	Cause rapid blood sugar spikes, increasing risk of diabetes and related cognitive issues.	Promote stable blood sugar levels due to fiber content.
Processing & Additives	Contain industrial ingredients and chemical additives with potential neurotoxic effects.	Contain no additives, preservatives, or artificial ingredients.

Strategies for Reducing UPF Consumption

To improve cognitive health, reducing or eliminating UPF intake is a key dietary goal. Small, sustainable changes can yield significant long-term benefits.

Start Gradually: Begin by substituting one or two UPF items in your daily routine with a healthier alternative. For instance, swap a sugary breakfast cereal for a bowl of oatmeal topped with fresh berries.

Read Food Labels: Pay attention to the ingredient list. UPFs often have long lists of ingredients, including additives, preservatives, and names you don’t recognize. In general, a shorter ingredient list is better.

Cook More at Home: Preparing your own meals from scratch using whole ingredients gives you complete control over what you consume. Making homemade versions of snacks like bread, dressings, or baked goods is an excellent strategy.

Embrace Whole Foods: Focus your diet on unprocessed and minimally processed foods like fruits, vegetables, whole grains, nuts, seeds, and lean proteins. Shopping the perimeter of the grocery store is a great way to prioritize these foods.

Stay Hydrated: Replace sugar-sweetened beverages with water. Dehydration can impair cognitive function, and sugary drinks are a major source of UPFs.

Visit Harvard Health Publishing to learn more about the link between diet and cognitive function.

Conclusion

The evidence linking higher consumption of ultra-processed foods with accelerated cognitive decline and increased dementia risk is substantial and growing. The detrimental effects are rooted in the inflammatory nature of these foods, their negative impact on the gut microbiome, and the presence of harmful additives. By displacing whole foods, UPFs contribute to a nutrient-deficient diet that fails to support a healthy brain. Fortunately, adopting healthier eating patterns rich in whole, minimally processed foods can help mitigate these risks and support long-term cognitive health, making mindful dietary choices a powerful tool for protecting brain function as we age.

Frequently Asked Questions

Ultra-processed foods are industrial formulations made mostly or entirely from substances extracted from foods, like fats, sugars, starches, and protein isolates, often containing additives. Examples include packaged snacks, sodas, instant noodles, and frozen meals.

UPFs can cause cognitive decline through several mechanisms, including promoting chronic inflammation, disrupting the gut-brain axis, causing blood sugar fluctuations, and introducing potentially neurotoxic additives.

Most current evidence comes from large observational and cohort studies showing a strong association, but cannot prove direct causality. However, the consistent findings and identified biological mechanisms suggest a high probability of a causal link.

Processed foods (e.g., canned vegetables, cheese) have undergone basic processing but retain most natural characteristics. Ultra-processed foods are extensively processed industrial formulations with added chemicals, flavorings, and little or no whole food content.

While it may not reverse all damage, adopting a healthy diet rich in whole foods, like the MIND or Mediterranean diet, is associated with better cognitive function and can help reduce the risk of further decline. Small changes can have a significant impact over time.

While the impact of all additives is not fully understood, some, like certain emulsifiers and sweeteners, have been linked to negative effects on the gut microbiome and potentially the brain. The cumulative effect of many additives is a concern for long-term health.

Start by making small substitutions, such as swapping sugary cereal for oatmeal, using homemade sauces instead of store-bought ones, and replacing packaged snacks with fruits or nuts. Focusing on cooking at home with whole ingredients is also very effective.