How Ultra-processed Foods Affects Gut-Brain Axis

A recent study investigated the link between ultra-processed food consumption and gut-brain axis dysfunction.

What is the Gut-Brain Axis?

The gut-brain axis is a bidirectional communication system between the gastrointestinal tract and the central nervous system, which influences various aspects of our health, such as metabolism, immunity, mood and cognition.

What are Ultra-processed Foods?

Ultra-processed foods are those that undergo several industrial processes and contain additives, such as

  • sugar,
  • salt,
  • fat,
  • preservatives and
  • flavor enhancers.

Examples of ultra-processed foods are

  • soft drinks,
  • chips,
  • candy,
  • instant noodles,
  • frozen meals and
  • fast food.

The study, published in the journal Nutrients, analyzed the dietary habits and gut microbiota composition of 132 adults from Spain. The researchers found that higher consumption of ultra-processed foods was associated with lower diversity and richness of the gut microbiota, which are indicators of a healthy gut.

Moreover, they found that ultra-processed food consumption was correlated with higher levels of inflammatory markers and lower levels of short-chain fatty acids (SCFAs) in the feces.

What are SCFAs?

SCFAs are short-chain fatty acids that are beneficial metabolites produced by the gut bacteria that have anti-inflammatory and neuroprotective effects.

The researchers also assessed the participants’ cognitive function, mood and mental health using various tests and questionnaires.

They found that higher consumption of ultra-processed foods was associated with poorer cognitive performance, especially in memory and executive functions.

Additionally, they found that ultra-processed food consumption was linked to higher levels of anxiety, depression and stress.

The study suggests that

  • eating too much ultra-processed food may have negative consequences for our gut microbiota and our brain health.
  • ultra-processed food may disrupt the gut-brain axis by altering the composition and function of the gut bacteria, which in turn may affect the production of neurotransmitters and neurotrophic factors that regulate brain function and behavior.
  • ultra-processed food may induce inflammation and oxidative stress in both the gut and the brain, which may impair neuronal function and plasticity.


The authors conclude that their findings support the hypothesis that ultra-processed food consumption may be a risk factor for developing neuropsychiatric disorders, such as depression, anxiety and cognitive impairment.

They recommend reducing the intake of ultra-processed food and increasing the consumption of whole foods, such as fruits, vegetables, nuts, seeds, legumes and whole grains, which are rich in fiber, antioxidants and phytochemicals that can benefit both the gut and the brain.

Download the article about the research Written by Bhavana Kunkalikar in

Bhavana Kunkalikar is a medical writer based in Goa, India. – An AZoNetwork Site




Song, Z., Song, R., Liu, Y., Wu, Z., & Zhang, X. (2023). Effects of ultra-processed foods on the microbiota-gut-brain axis: The bread-and-butter issue. Food Research International, 167, 112730.