You no longer need to fear that injection. Saliva from your mouth can now be
used effectively for diagnostic purposes.
One of the most common body fluids used for diagnostic purposes is blood. However, the act of jabbing a needle into the body to extract blood frightens many. And then there is the problem of cross infection. Is there an alternative to blood? Pathologists are finding it in everyone's mouth - the saliva.
The medicinal value of saliva has been known for some time. It acts as a buffer to keep the mouth slightly alkaline and prevent the growth of bacteria. A wound in the cheek or gum heals much faster and without a scar, unlike on the skin. That is because saliva has a protein called vascular endothelial growth factor, which promotes formation of new blood vessels.
Now the saliva is revealing its diagnostic potentials also. It contains a number of telltale markers, which can foretell the health status of an individual from microbial infection to cancer. One of the most investigated markers is the hormones - particularly the steroid hormones such as estrogen, progesterone, testosterone, cartisol, DHEA's.
These hormones, secreted by different glands in the body, play a vital role in our physical, mental, and emotional health. Since some of them have mutually opposing influences on the body, a delicate balance is essential for health. Any disturbance in this balance portends trouble. For example, an excess of estrogen in middle-aged women can be indicative of endometriosis- a condition in which uterine tissue migrates into other parts of the body such as womb, pelvis colon causing pain during menstruation.
Similarly 'estrogen dominance' may also cause uterine fibroids in which the uterus grows unchecked, resulting in heavy bleeding and painful periods or polysystic ovaries - a condition in which numerous cysts develop in the ovaries. Generally these are benign and shrink or even disappear when hormonal imbalance is corrected.
Estrogen dominance can also block the action of thyroid hormones and lead to hypothyroidism with symptoms like feeling cold all the time, weight gain or unable to lose weight, sleep disturbance, fatigue, mood swings, depression, etc. While a normal level of estradiol, but subnormal level of progesterone, may lead to infertility in women, low levels of both may indicate other complications such as loss of bone density and osteoporosis.
In men low testosterone level may be associated with excessive fatigue, loss of libido and mental lethargy. And the list goes on.
A tiny portion of the hormones circulating in the blood enters the salivary gland through the capillaries and appears in the saliva. The amount of a hormone in saliva is measured by a highly sensitive procedure known as radioimmuno assay. Determination of the hormone profile in saliva, in conjunction with the symptoms can pinpoint the problem.
Saliva assays can also test for stress related hormones such as cartisol and DHEA in both children and adults.
How reliable are the saliva tests? Many laboratory studies have shown good correlation between levels of steroid hormones in blood and in saliva. In fact, the hormone levels in saliva, unlike in the blood, indicate the free or bioavailable hormones, the one that actually works at the cellular level. It also reflects more accurately the uptake of topical hormone supplementation through skin creams and gels.
Another important aspect of saliva testing is the stability of the sample. Unlike blood or serum samples, which need to be maintained at low temperatures, saliva samples can be stored at room temperature. The hormones remain stable for at least one week Hormonal profile is not the only diagnostic information one can get from saliva. It is known to contain antibodies to the HIV and to those viral and bacterial culprits that cause respiratory diseases in children. Scientists at the National Institute of Dental and Cranifacial Research, USA, have reported measuring elevated levels of four distinct cancer associated "messenger RNA" molecules in saliva.
They have been able to distinguish with 91 per cent accuracy between healthy people and those diagnosed with oral squamous cell carcinoma and hope to push this limit further. They are also experimenting to see if saliva contains a wider range of messenger RNA profiles for diagnosing not only different cancers, but also other diseases.
If they succeed, no more needle jabs, just a vial full of saliva will do.