Tuesday, July 21, 2015

The Predictive Power of Spit

Research presented at the 2015 Alzheimer's Association International Conference on Sunday suggests that it may be possible to use saliva as a diagnostic tool in predicting Alzheimer's disease.  Alzheimer's causes changes in the body years before any symptoms occur and early diagnosis is key, as it is in other diseases, for early treatment and better outcomes.

While this particular study is preliminary and needs to be reviewed and replicated, the predictive power of spit has already been harnessed for other diseases and conditions.  Saliva tests for HIV have been used by medical professionals since the early 2000s and in 2012 the FDA approved a home testing kit for consumers.  According to the National Institutes of Health there are also saliva tests available for hormonal problems and to screen for substance and alcohol abuse.

Oh, spit! 

(photo: Y. Mikalopas)

In dentistry, the importance of healthy saliva has long been recognized as critical for oral health.  In addition to keeping the mouth moist and aiding in digestion of food, saliva contains a host of substances including immune factors, proteins, bacteria, and minerals.  Saliva tests that examine the type of bacteria in the mouth can be used to suggest treatment options for patients at risk for cavities and gum disease.  There are also tests that look at salivary flow, which can aid in treatment of dry mouth.

Saliva tests that examine protein markers, like the preliminary one for Alzheimer's, could potentially be predictive of systemic diseases like cancer.  A study of head and neck cancers at John Hopkins used saliva and blood testing which reliably found DNA markers in the saliva of patients with these cancers.  Changes and differences in proteins in the saliva have also been found in other patients with cancer, such as women with breast cancer.

There is no downside to saliva testing as a diagnostic tool.  Saliva tests that currently exist are easy to use, non-invasive, reliable and relatively inexpensive.  Imagine a future without the need for invasive procedures like biopsies or uncomfortable screenings like mammograms - where a yearly saliva test, done quickly in a doctor's office or at home, could reliably predict disease and result in early intervention and treatment.  

Sources: Alzheimer's Association International Conference (2015). Researchers Report New Ways to Predict the Development of Alzheimers Disease (Press Release). Retrieved from https://www.alz.org/aaic/releases_2015/Sun-8amET.asp; National Institutes of Health, Fact Sheet, Salivary Diagnostics; Y. Wang, S. Springer, et al. "DNA Shed from Head and Neck Tumors Detected in Blood and Saliva," Hopkinsmedicine.org, 24 June 2015; A. Nieves, W. Fitzgerel-Blue. "Saliva: Of Emerging Importance in the Medical and Dental Worlds," rdhmag.com.

This information is not intended to diagnose or treat any condition. Please see your dental or medical professional for treatment and advice.


  1. What do you think about saliva testing? I welcome your comments.

  2. I think this is great. It in noninvasive, so as you mentioned there is almost no downside. And the results could be compared with other current testing, and further test its validity.

    1. Thanks for your insightful comment. Current saliva tests, such as those used for HIV seem to be very reliable. Hopefully additional research proves saliva testing to be a useful tool for a broad range of conditions.


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