Exploration of the Gut–Brain Axis through Metabolomics Identiﬁes Serum Propionic Acid Associated with Higher Cognitive Decline in Older Persons

Nutrients, 2022 · DOI: 10.3390/nu14214688 · Published: November 5, 2022

Simple Explanation

This study explores the connection between gut bacteria byproducts and cognitive decline in older adults. Researchers measured various metabolites in blood samples from a large group of older people. They found that higher levels of propionic acid, a short-chain fatty acid, were associated with a greater risk of cognitive decline over a 12-year period. Further analysis suggests that this link might be partly explained by hypercholesterolemia and diabetes, indicating a potential pathway involving metabolic health.

Study Duration

12 years

Participants

838 older persons (discovery n = 418; validation n = 420)

Evidence Level

Not specified

Key Findings

1
Higher serum levels of propionic acid were associated with increased odds of cognitive decline.
2
Propionic acid strongly correlated with blood glucose and with intakes of meat and cheese, but not fiber.
3
Additional analyses suggested mediation by hypercholesterolemia and diabetes.

Research Summary

The gut microbiome is involved in nutrient metabolism and produces metabolites that, via the gut–brain axis, signal to the brain and inﬂuence cognition. Higher serum levels of propionic acid, a short-chain fatty acid, were associated with increased odds of cognitive decline The adverse impact of propionic acid on metabolism and cognition deserves further investigation.

Practical Implications

Dietary Considerations

The study suggests a possible link between processed foods containing propionic acid as a preservative and cognitive decline, warranting further investigation into dietary sources of propionic acid.

Metabolic Health

The mediating role of hypercholesterolemia and diabetes highlights the importance of managing metabolic health as a potential strategy to mitigate the adverse impact of propionic acid on cognitive aging.

Further Research

The adverse impact of propionic acid on metabolism and cognition deserves further investigation to elucidate the underlying mechanisms and potential therapeutic targets.

Study Limitations

1
The sample size could still be insufficient to ensure adequate statistical power.
2
Serum samples were analyzed at the study baseline only; therefore, we could not examine longitudinal changes in the serum metabolome during the course of cognitive decline.
3
The metabolite panel was large, it did not cover all metabolites of the gut–brain axis

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