5 Facts about Spit | What’s in Saliva?
An underappreciated body fluid isِ emerging asِ a powerful tool forِ research, medical diagnosis andِ health.
According toِ researchers atِ Johns Hopkins University’s Center forِ Interdisciplinary Salivary Bioscience Research — yes, a research center dedicated toِ spit — saliva holds a treasure trove ofِ data thatِ isِ easily collected andِ inexpensively analyzed.
It hasِ the potential toِ expose secrets ofِ human biology andِ genetics, asِ well asِ helping combat disease.
But what can spit do for you?
One-third ofِ heart attack victims drop dead withoutِ everِ knowing theyِ hadِ high cholesterol, hypertension orِ the otherِ factors thatِ increased theirِ risk ofِ cardiac arrest.
That’s partly becauseِ the blood test currentlyِ used toِ diagnose a person’s heart disease risk is quiteِ the ordeal — it’sِ painful, requires a clinic visit, andِ takes weeks toِ beِ processed — andِ so mostِ people don’tِ take itِ asِ often asِ they should.
According toِ theِ researchers, spit containsِ the sameِ protein, called C-reactive protein, thatِ indicatesِ a risk ofِ heart disease whenِ foundِ in blood atِ elevated levels, andِ spit canِ therefore give a rough proxy ofِ a patients’ heart health.
Your father’s daughter?
As detailed inِ a recentِ paper byِ Granger andِ his team, theِ answer mayِ beِ swimming inِ spit.
The researchers foundِ that whenِ a girl’s father-daughter relationship isِ characterized byِ rejection, chaos andِ coercion, herِ saliva exhibits lower-than-normal levels ofِ the stress hormone cortisol inِ the morning, andِ elevated cortisol levels whenِ sheِ isِ discussing problems orِ anxieties withِ friends.
Salivary signs of stress
Stress triggers theِ body’s fight-or-flight response, causing, among otherِ things, a rush ofِ adrenaline, anِ increased heart rate andِ salivation.
The salivary glands flood theِ mouth withِ anِ enzyme called salivary alpha-amylase (sAA), andِ this canِ serve asِ a marker ofِ stress.
The Johns Hopkins team hasِ developed a method ofِ gauging theِ impact ofِ a mother’s stress onِ herِ unborn baby byِ monitoring sAA levels inِ herِ saliva.
Pre-mastication — theِ act ofِ pre-chewing adult food andِ feeding itِ to one’sِ baby — wasِ standard practice among ourِ blender-lacking ancestors andِ remains common inِ many ofِ the world’s cultures.
By exposing infants to traces ofِ disease pathogens present inِ a mother’s spit, pre-mastication gears upِ theirِ production ofِ antibodies, teaching theirِ immune systems howِ to deal withِ thoseِ sameِ pathogens laterِ inِ life.
It couldِ alsoِ reduce theirِ risk ofِ the autoimmune diseases, suchِ asِ asthma, thatِ areِ common inِ industrialized countries — epidemiology evidence indicatesِ that theseِ ailments result fromِ underexposure toِ pathogens beforeِ age 2.
Your spit containsِ your entire genetic blueprint, andِ in a form thatِ mayِ beِ easier toِ work withِ thanِ DNA extracted byِ other methods.
They canِ beِ sent throughِ theِ mail, andِ we’re able toِ extract high-quality, high-quantity DNA.
Follow Natalie Wolchover onِ Twitter @nattyover.