Oral bacteria in Alzheimer’s brains.

Recently, researchers were amazed to find a seven-fold increase in bacterial counts in the brains of patients with Alzheimer’s disease. Specifically, they found that the increase was mainly due to the presence of oral bacteria, the bugs that make up the microflora of the mouth.  A number of previous studies have shown that poor oral hygiene and loss of teeth are associated with an increased risk of developing Alzheimer’s disease.  This study moves that idea forward by using a new method to measure bacterial load and compared the post-mortem brains of eight patients with Alzheimer’s disease to the brains of six deceased patients without dementia.  In line with the small sample sizes, this was a pilot study and will need to replicated.

The authors suggest that these bacteria may play a role in the inflammatory response that is known to occur in the brains of patients suffering from Alzheimer’s disease.  While the idea that poor oral hygiene may be a risk factor for dementia, alternative explanations for these findings should also be explored.  For instance, the finding might not be due to bacteria causing dementia, but rather could simply reflect the fact that demented patients have greater difficulty maintaining oral hygiene than cognitively normal people.  Still, these findings are yet another reason to use dental floss every night!

If you’d like to read the original research, please click here.


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