Sep 252013

British scientists recently reported finding signs of the gum-disease bacterium toothbrush (P. gingivalis) in the brains of Alzheimer’s patients. The new study is being widely reported as adding to a growing body of evidence linking periodontal (gum) disease to an increased risk for Alzheimer’s disease.

However, such data needs to be considered very carefully.

In fact, what the study found was that substances on the surface of the bacterium (lipopolysaccharides) were present in the brain tissue of four out of 10 recently deceased people who had Alzheimer’s. It was found in zero out of 10 age-matched patients who did not have Alzheimer’s. The bacteria itself was not found in the brain tissue of any people.

The theory behind linking gum disease with Alzheimer’s is that the presence of gum bacteria lipopolysaccharides in the brain may cause inflammation. This in turn could trigger a biological cascade that may be linked to the brain changes associated with Alzheimer’s disease.

We already know that P. gingivalis is commonly found in chronic periodontal (gum) disease, and, if there is significant dental disease, it can enter the bloodstream through such everyday activities as eating, brushing teeth and invasive dental treatments. While in the bloodstream, the bacteria can settle on heart valves and damage them. Hence, patients with mitral valve prolapse and other heart anomalies often take an antibiotic before dental procedures to prevent the bacteria from depositing within the heart. However, no bacteria have been reported in the brains of patients with gum disease, as the brain is an immunologically, well-protected organ, more so than any other.

It is important for readers to know that these types of studies show an association between gum disease and Alzheimer’s disease, but do not prove causation. For example:

  • The number of subjects is extremely small to make a definitive conclusion, and the finding could have occurred simply by statistical chance.
  • Only four out of 10 subjects with Alzheimer’s had such changes, not 10 out of 10. If the gum disease was causative, one would expect more than just a minority of patients exhibiting the lipopolysaccharides.
  • Finally, what if very early stage dementia caused people to actually brush their teeth less often, or altered their dietary intake? They would be at risk of developing gum disease. But the gum disease would have resulted from the early dementia, not vice versa.

It is also important to note that previous studies have shown links between gum disease and other illnesses, including heart disease and certain forms of cancer; these findings are not specific to Alzheimer’s.

The study is important and should be followed up with larger sample sizes, but given the above limitations, the study does not show that “brushing teeth reduces the risk of dementia” or that “gum disease can lead to dementia.”

Thanks for reading.

Michael S. Rafii, M.D., Ph.D.

Director, Memory Disorders Clinic
Associate Medical Core Director, Alzheimer’s Disease Cooperative Study
University of California San Diego

This post originally appeared in Alzheimer’s Insights, an ADCS Blog.

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  6 Responses to “Is Alzheimer’s Really Linked to Poor Dental Health?”

  1. Great article! Thanks for sharing and I am looking forward to more information the subject. I've seen my share of Alzheimer's patients as a practicing general dentist in Mebane, NC, and those of them with their share of gingivitis and periodontal disease. I'm sure as time goes on we'll be learning more and more the role or oral bacteria in systemic health.

    Thanks again,
    Eric Steinbicker, DDS

  2. Dear Doctors.

    I was wondering if you could tell me how can I find out if I do have the bacteria lipopolysaccharides in my gums? My mom have Alzheimer's for 9 years now. She no longer doesn anything by herself, she doesn't eat alone, walk alone, drink alone or even hardly talk. My aunt, dad's sister also have an Alzheimer's disease for 7 1/2 years now. I have experience some lost of memory, along with "all" other symptoms. I need to know what are the tests I can do to be sure if I have it or not? What are my chances if I discover early as 49 years old, as I have it now?

    Thank you very much.


  3. Thank you for sharing. The best practise is not to draw ANY hasty conclusions about such findings as this, without further comprehensive study. I would even not encourage posting news like this because all they cause is confusion. Neurological diseases, such as Alzheimer's and Supranuclear Paralysis (PSP), Parkinson's – they all share something in common; assumptions, publications of unfinished studies, drawing too-early-conclusions and assuming something. Many of the known factors are the same withing all of these diseases, whereas a wide spectrum of hypotesis and suggestions shadow the major part of the rest. It might be lack of education, poor dental health and so on that is thrown to the public as something that might have something to do with a disease. On the otherhand, what we know for sure is the lack of evidence and certainity for that wide spectrum of other affecting or possibly affecting factors which may or may not contribute to the development of any of the mentioned diseases within a single individual. What I consider grazy is how posting hasty conclusions or suspicions based on some whatever findings made that have no medical proof if at the time of writing if it actually does contribute to the disease or just "suggests to", and then when posted put the disclaimer that "study does not show that “brushing teeth reduces the risk of dementia” or that “gum disease can lead to dementia.” SO all what this does is cause unnecessary scatter and disturbance and further confusion. Plus that it may even increase the sales like in this case for toothpaste and toothbrush manufacturing companies. Soon they will add a statement into their paste for advertisement to increase sales "Daily use of our toothpaste and daily regular toothcare may lower your chances in developing Alzheimer's". This to me suggests that in order to cover the lack of advance in the medical science we are being provided these faint assumptions and hasty conclusions in order to cause distraction from the poor performance. Let's not forget the wide spectrum of other possible factors contributing in developing these neurological diseases; just one word actually: "Environmental Factors". There you go. Now you can basically put almost ANYthing under that title. This is simply because the spectrum of EFs is so wide that there is no chance ever to find out which specific factors contribute to what in the rise of the disease, because there might be combinations amount of X that may be needed or the environmental factors X plus the other factors Y e.g. poor dental health or lack of high education and then Z inherited genes and..and…and…you name it. As many as you want in as many combinations as you want. This is why there IS NO CURE. There is NO drug that can prevent these diseases for occurring. There is NO drug that can save a person once diagnosed. All we HAVE is this posting of time after time more amazing NEWS that really do NOT HELP. All they DO is cause MORE CONFUSION. You draw your own conclusion WHY they want to distract us with throwing these FINDINGS to our faces now and then.

  4. Firstly, how old is this information? There's no date on the article that I can see. My wife was diagnosed with Early Onset Alzheimer's six years ago at the age of 56 and now entering into what appears to be the latter stages of the disease. The maze of information I've had to engage for researching this nightmare nefarious attack is quite daunting. And to now find this information with respect to the disease being possibly tied to dental health is quite alarming. My wife decided to have braces put on at the late age of 40 and still has what appears to be a permanent retainer inside her lower mouth. This is quite concerning, for a couple of reasons; 1) the possibility of slow leaking metal contamination being the ultimate culprit and now 2) this new information about the possible connection to gum disease and any caregiver can testify to the sheer nightmare experience of trying to maintain proper oral hygiene with an Alzheimer's patient. Anyhow, I'm thankful for the information and will not log into the bevy of info I've collected over the years.

  5. DUDE! I am so excited right now after reading this! Thaaaaankkk you!

  6. Thank you for sharing this one. I read other blogs and articles too regarding Alzheimers/Dementia to Dental Health. They say it is due to the Alzheimers/Dementia bacteria in the brain of the patients. I also read some stating that the drugs for Alzheimers/Dementia can cure tooth problem.

    On my opinion, possible cause of the dental health issues of patients with Alzheimers/Dementia is due to neglected Oral care. They neglect the oral care possibly due to their Alzheimers/Dementia condition.

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