Key takeaways

Saliva production, ranging from one to two liters per day, is crucial for digestion, oral health, and can indicate various health conditions.
A decrease in saliva production can lead to dry mouth, affecting digestion and oral health, while an increase may signal pregnancy, medication side effects, or underlying health issues.
The consistency and taste of saliva, such as thick or bitter saliva, can indicate oral infections or acid reflux, necessitating medical consultation.
Saliva testing is gaining traction in healthcare for diagnosing diseases like Alzheimer’s and HIV, and for non-invasive monitoring of conditions like Cushing’s disease and potentially diabetes.

Your spit not only softens your food—emerging research suggests it can help maintain your overall health.

A person produces one to two liters of saliva per day, according to LiveScience. That’s a lot, but for all the chewing, digesting, and drooling we do, it’s a range that actually makes sense.

Saliva had often been overlooked as an indicator of your overall bodily health in the past, but saliva testing is now frequently being used as an efficient, cost-effective alternative to traditional evaluations of your overall bodily health.

Spit it out: Saliva can signal a health problem

There are numerous digestive functions of saliva—like moistening food, breaking it down, and enhancing taste—but the importance of saliva goes beyond digestion. It’s also essential for good oral health. According to the American Dental Association, saliva washes food away from your teeth and gums, which helps to prevent cavities and other oral infections such as strep throat. A lack of it, however, can signify a whole different range of health problems.

Dry mouth

A decrease in the amount of saliva produced, known as dry mouth, can negatively impact digestion and appetite, according to the Mayo Clinic. There are some telltale signs of having dry mouth: not only dryness of the mouth, but also thick or foamy saliva, difficulty chewing and swallowing, irritation of the gums, and tooth decay.

On one side, dry mouth can be caused by poor health and on the other side, dry mouth can be a side effect of taking prescription medications.

Excess saliva

On the flip side, an increase in the amount of saliva, known as hypersalivation or excess saliva, can also signal a problem. It can be a side effect of pregnancy or certain medications. But it can also indicate an underlying oral infection, acid reflux, or a neuromuscular disease like Parkinson’s, according to Colgate.

Thick white saliva

The consistency of your saliva is also useful in identifying an oral infection. Thick saliva or white saliva may be a sign of a fungal infection called thrush, according to Prevention. In these cases, the best solution is to see your doctor. You may need an antifungal prescription.

Bitter taste in the mouth

Bitter saliva can also raise red flags. It’s often a symptom of acid reflux, a condition that causes stomach acid to rise up into your mouth, according to Health.com. Acid reflux increases the acidity of your mouth, and can actually wear away teeth and cause cavities. These bitter tastes often emerge at night, and a doctor can test the pH of your mouth to see if you’re affected.

Saliva as a science

Spit can also be a bellwether for more serious diseases. According to The Washington Post, saliva can tell doctors whether an individual is at risk for Alzheimer’s, even before memory loss occurs.

It may also be used to determine a patient’s risk of HIV infection, according to research from the Johns Hopkins Center for Interdisciplinary Salivary Bioscience Research. Doug Granger, the director of the study, explains that saliva has been used since the 1990s as a viable alternative to blood and urine samples.

In fact, decades-old research published in the New England Journal of Medicine provided evidence that the molecules found in saliva are actually connected to HIV.

And for Cushing’s disease patients, saliva may provide a non-invasive and less costly way to measure cortisol levels as a test to help its diagnosis. There is research underway to measure glucose levels in saliva to help in diabetes management, at least according to research from Purdue University.

At home saliva-testing kits, like 23andMe and Ancestry.com, have taken saliva testing even further. With just a swab and some spit, they offer to decode where your family is from and what diseases you may be at risk of contracting.

In all, oral fluid diagnostics are growing in popularity across the healthcare industry, as dentists and other medical professionals seek to expand and improve preventative medicine.