Scientists believe they've found the secret behind Alzheimer's disease: your gums.
Researchers from the firm Cortexyme say their latest study reveals that chronic gum disease is the cause of the deadly disease. They identified a specific bacteria called P. gingivalis as the culprit.
"Bacteria involved in gum disease and other illnesses have been found after death in the brains of people who had Alzheimer's, but until now, it hasn't been clear whether these bacteria caused the disease or simply got in via brain damage caused by the condition," New Scientist reports.
Researchers discovered that P. gingivalis can invade the brain and inflame brain regions affected by Alzheimer's. Cortexyme found that the bacteria fed on human tissue in 96 percent of the Alzheimer's brain samples they examined.
The team found that the bacteria destroys "tau" protein in a way that allows it to kill neurons, which causes dementia. People who experienced worse cognitive decline had higher levels of P. gingivalis and its enzymes in their brain.
P. gingivalis was also found in the spinal fluid of living people with Alzheimer's, suggesting that doctors may now be able to diagnose the disease by testing spinal fluid.
"When the team gave P. gingivalis gum disease to mice, it led to brain infection, amyloid production, tangles of tau protein, and neural damage in the regions and nerves normally affected by Alzheimer's," New Scientist reports.
The firm confirmed what many scientists suspected but had yet to prove – gum disease can actually destroy your brain.
"When science converges from multiple independent laboratories like this, it is very compelling," Casey Lynch of Cortexyme told the paper. "Alzheimer's strikes people who accumulate gingipains and damage in the brain fast enough to develop symptoms during their lifetimes. We believe this is a universal hypothesis of pathogenesis."
The results of the study are concerning, considering gum disease affects half of all adults age 30 and higher, according to the Centers for Disease Control and Prevention.
The good news is scientists say they already know how to fight Alzheimer's.
Cortexyme developed molecules that block enzymes secreted by P. gingivalis. After giving some to lab mice, it lowered brain inflammation, reduced infections, and even saved damaged neurons. The medication has passed initial safety tests on people and even seemed to improve patients with Alzheimer's.
The firm will launch a larger trial of the drug later this year and plans to test if they can even stop gum disease.