Saliva diagnosis, biomarkers: Spit mirrors health better than blood; saliva tests gaining momentum; could predict diseases well in advance; accurately diagnose health issues
By Syed Akbar Hyderabad: Spit has always been considered something derogatory and insulting, but nowIndian scientists and doctors have reopened the 2000-year-old secret about this wonderfulfluid. Spit or saliva is more than a chemical secretion in the mouth. It is a reflectionof one’s health – both mental and physical, city researchers point out. The importance of saliva in diagnosis of diseases was extensively dealt with in ancientIndian medical records as old as 2000 years. Sushruta Samhita had made several referencesto saliva in diagnosis and treatment of certain diseases including oral cancers. But, for almost two millennia the importance of saliva in diagnosis and treatment ofdiseases was under wraps. Digging into old Indian medical records, doctors andresearchers in the country have rediscovered the significance of saliva as a non-invasiveand painless diagnostic tool. Of late, many Indian scientists have taken up research on saliva and developed biomarkersfor a plethora of diseases. Saliva is both predictive and diagnostic in nature – it notonly predicts well in advance whether a particular individual is pre-indisposed to aparticular disease, but also tells doctors what disease an individual is suffering from. If the fast-paced research on saliva is any indication, saliva will soon emerge as themost preferred diagnostic tool for diseases and disorders. Though they may not altogetherreplace the blood tests, saliva tests will come handy for small children and the elderly.Moreover, unlike blood tests which have to be largely carried out in a laboratory, salivatests can be done in the privacy of one’s home or office, researchers point out. Doctors at the city-based Nizam’s Institute of Medical Sciences have already successfullyutilised both these (predictive and diagnostic) properties of saliva. They helped in thedevelopment of biomarkers for diabetes. Researchers elsewhere have found out that salivais capable of informing whether or not a woman is pregnant. All that a woman, who wantsto test her pregnancy, has to do is to spit on a special strip. The medicated strip willinform her if she is carrying. The NIMS-aided glycoproteomase tests can be conducted athome. A diabetic needs just to spit on the glycoproteomase strip and within no time, he or she will be able to know glucose control in the blood. Ancient medical records have equated saliva with blood. Modern doctors hundreds of yearslater, point out that saliva is indeed a better diagnostic tool than blood. Says Dr PVRao, head of the department of diabetology, Nizam’s Institute of Medical Sciences,“saliva mirrors blood. In fact, the diagnostic results obtained from saliva are betterthan those obtained from the blood. Saliva tests are painless and non-invasive. There’sno need for painful needle pricks for blood tests. In case of diabetics, dozens of blood tests are conducted every year. Saliva glycoproteomase tests may replace blood tests fordiabetes”. Doctors at NIMS took up the research on saliva as it is almost reflection of what lies in the blood. Study of saliva will inform doctors about the changes or otherwise in the blood. Saliva tests are convenient, handy and easyto carry out. Saliva can be stored for longer periods unlike the blood. According to senior oral pathologist and microbiologist Dr Manjul Tiwari, diagnosis andprevention of diseases using human saliva is about to be explored as more and morelaboratories and medical practitioners get ready for this new technology. “Unlike bloodtesting, saliva analysis looks at the cellular level, and therefore, saliva is truly arepresentative of what is clinically relevant,” he points out. Blood analysis, on the other hand, looks at compounds as they travel through the bloodserum. Saliva analysis will predict, diagnose, or prevent many health problems anddiseases. “Molecules freely travel through the cells and into saliva ducts and it isthese small molecules that can be assayed in saliva,” Dr Tiwari said. Researchers point out that saliva tests will help in identifying health issues relatingto heart, skin, cancers, and infertility. Diseases like diabetes can be predicted atleast 10 years in advance through saliva tests. Cholesterol, sleep disorders, sleepdisorders, baldness in men, allergies can also be identified through spit analysis. “Other areas where saliva diagnostics will of great help include oral carcinoma, salivarygland disorders/diseases, some benign and malignant tumors, dental caries and disordersor diseases due to drugs. In India, saliva tests are yet to take off on a large scale.Hospitals in a few areas are using saliva as a diagnostic kit and in many cases it ismuch more effective than blood,” he said. According to Dr Rao, a number of proteins have been identified in human saliva. Most ofthe proteins identified in saliva are also present in blood. Saliva diagnostics arefaster and cheaper than blood tests. The diabetes tests using saliva samples will beavailable for the common man in the next few months. “It works like thermometer. Put the saliva glycoproteomase strip in the mouth and theresult is displayed within a few seconds. Unlike blood sugar tests where blood samplingis done before and after meals, saliva test can be done only once. This saves time andmoney for diabetics,” he adds. Stating that while saliva tests won’t replace blood tests for all diagnosticapplications, Dr Tiwari argues that in future they could prove to be a potentially“life-saving alternative to detect diseases where early diagnosis is critical, such ascertain cancers”. “If we could read the stories of diagnostic information present within saliva, then theabundance of information waiting to be found could be comparable to a vast vault ofinformation such as the internet,” Dr Tiwari adds.
----------------------- Facts about saliva diagnostics ----------------------
* A diabetic patient with uncontrolled blood sugar undergoes 100 blood tests a year on anaverage. Sugar control in the body can be found out through saliva tests. Saliva test ispainless, easy and more reliable than a blood test. Just spit on a strip and the resultis out in no time. * Saliva test is convenient for young children and the elderly and those who do not wantto be pricked by a needle. * Saliva analysis will reveal well in advance whether an individual is likely to developa particular disease at a later stage in life. Biomarkers for a number of diseases arebeing developed. * Saliva will inform whether a woman is pregnant. Progesterone levels in saliva aremeasured to confirm pregnancy. * Saliva tests will indicate about an impending heart problem. They will tell us thelevel of cholesterol in the blood. * Though saliva tests have assumed importance of late, spit was used as a diagnostic toolby doctors in ancient India, China, Greece and Rome. In olden days the smell andthickness of saliva was measured to identify diseases including cancers. * Saliva gives a better picture of the physiology of the body than blood. * Presently, swine flu or novel human influenza H1N1 is diagnosed through saliva orthroat swab. Even tuberculosis is diagnosed through spit. * Development of saliva biomarkers for diseases will help in better surveillance ofhealth.