There’s a New Link Between Gut Health and Alzheimer’s Disease

Scientists have discovered a potential link between gut health and Alzheimer's disease. A study published in Nature Communications identified a molecule named imidazole propionate (ImP), produced by certain gut bacteria, as a possible connection between the microbiome and Alzheimer's disease. The researchers delved into this chain of events, starting from the gut to the brain.

ImP is generated by some bacteria that metabolize the amino acid histidine, and a portion of this molecule enters the bloodstream, eventually reaching the brain. Once inside the brain, ImP can compromise the blood-brain barrier, allowing it to enter the brain and interact with neurons. The two primary components of Alzheimer's disease—amyloid beta and tau proteins—are influenced by ImP.

The study found that ImP could exacerbate the accumulation of amyloid beta plaques and increase tau modification through phosphorylation. The researchers tested this chain of events in humans and mice, analyzing ImP levels in the blood of 1,196 cognitively healthy adults. Those with higher ImP levels scored worse on cognitive tests and exhibited higher levels of altered tau proteins and a protein linked to neuronal damage.

Furthermore, when ImP was administered to genetically modified mice prone to Alzheimer's disease, the signs of the disease worsened. Although several bacteria can produce ImP, they are not abundant in most individuals. The concentration of ImP that reaches the bloodstream depends on various factors, such as age, sex, genetics, diet, and microbiome composition.

While eliminating ImP-producing bacteria might seem like a viable solution, the researchers caution that this approach might be complex. Instead, they suggest targeting ImP itself or the bacteria responsible for its production, akin to how statins are used to lower cholesterol and reduce cardiovascular risk.