Part 7 - Eat yourself happy

The link between fiber, gut health and our mood is not just an interesting theory, it is based on solid scientific evidence.

The following studiesconducted by renowned research institutions worldwide, form the foundation for our understanding of these fascinating relationships. They impressively show how our diet - especially the consumption of fiber - can influence our mental health.

Let's take a closer look at these groundbreaking research findings.

1st study by the University of Oxford: Schmidt, K., Cowen, P. J., Harmer, C. J., Tzortzis, G., Errington, S., & Burnet, P. W. (2015). Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers. Psychopharmacology, 232(10), 1793-1801. https://doi.org/10.1007/s00213-014-3810-0

This research, published in the journal "Psychopharmacology", investigated the effects of dietary fiber on the processing of emotional information in the brain. The scientists gave participants dietary fiber or a placebo every day for three weeks.

After this time, they carried out tests in which the participants had to evaluate emotional facial expressions on a screen. The results were fascinating: the group that had taken dietary fiber showed reduced attention to negative information.

This means that these participants reacted less to negative emotional stimuli. In practice, this could lead to a more positive mood and improved emotional resilience. The researchers suspect that this effect is due to the production of serotonin in the intestine, which is promoted by dietary fiber.

2nd study by the University of California: Xu, L., Lam, T. H., Jiang, C. Q., Zhang, W. S., Zhu, F., Jin, Y. L., ... & Schooling, C. M. (2018). Dietary fiber intake is inversely associated with depressive symptoms in older adults. Scientific Reports, 8(1), 12090. https://doi.org/10.1038/s41598-018-30429-2

This extensive study, published in the "Journal of Affective Disorders", analyzed data from over 16,000 adults over a period of several years. The researchers compared the participants' fiber intake with their risk of developing depression.

The results were impressive: participants with the highest fiber intake had an 80% lower risk of developing depressive symptoms compared to those who consumed the least fiber.

It was particularly interesting that this correlation remained even when other factors such as general dietary quality, physical activity and social status were taken into account.

The researchers suspect that the anti-inflammatory properties of dietary fiber and its positive effect on the intestinal microbiome contribute to this protective effect.

3rd study by the University of Tsukuba: Miyake, Y., Tanaka, K., Okubo, H., Sasaki, S., & Arakawa, M. (2022). Intake of Soluble and Insoluble Fiber and Depressive Symptoms in Adults: A Cross-Sectional Study. Nutrients, 14(8), 1689. https://doi.org/10.3390/nu14081689

This study by the University of Tsukuba in Japan, published in the journal "Nutrients" in 2022, investigated the link between fiber intake and depressive symptoms.

The researchers found that participants with a higher fiber intake had a lower risk of depressive symptoms.

It was particularly interesting that this effect was more pronounced with soluble fiber.

4th study by University College Cork: Boehme, M., van de Wouw, M., Bastiaanssen, T. F., Olavarría-Ramírez, L., Lyons, K., Fouhy, F., ... & Cryan, J. F. (2019). Mid-life microbiota crises: middle age is associated with pervasive neuroimmune alterations that are reversed by targeting the gut microbiome. Molecular Psychiatry, 25(10), 2567-2583. https://doi.org/10.1038/s41380-019-0425-1

This further remarkable study was published in 2019 in the Journal of Nutritional Biochemistry. Scientists from University College Cork in Ireland investigated the effects of certain dietary fibers on stress and anxiety.

They found that the intake of these special dietary fibers increased stress resistance and had anxiety-relieving effects.

The study also showed changes in the composition of the gut microbiome that were associated with these positive effects.

These studies provide strong evidence for this, that fiber can positively influence not only our physical but also our mental health. They underline the importance of a high-fiber diet for our emotional well-being and show how closely the gut and brain are connected.