Like most bodily functions, saliva production is one you probably don’t think much about — well, until a food commercial comes on that turns your mouth into a drool factory.
Besides protecting the mouth from trauma during eating, swallowing and speaking, saliva is essential for maintaining oral hygiene by limiting the growth of germs in your mouth. It provides the proteins and minerals needed for protection, as well as the antimicrobial substances necessary to fight bacteria.
“It’s also the unsung hero of digestion,” Dr. Brooke Glessing, medical director of endoscopy at University Hospitals Cleveland Medical Center in Ohio, told HuffPost. “Saliva contains digestive enzymes, including amylase, that starts breaking down simple sugars and starch, and lipase, which starts fat digestion.”
Since saliva’s mostly made up of water, it’s usually clear-coloured and thin in viscosity. “However, underlying health issues can affect both the amount of saliva produced and contents of the saliva, which can result in changes to what it looks and feels like,” Glessing said.
It’s not unusual for saliva to change in consistency, taste and color throughout the day (and depending on what you’re eating), but if there are specific changes that seem to be sticking around, then you should check in with your doctor in case they’re due to an underlying health issue that needs to be addressed.
“Dehydration, autoimmune diseases and infections can all affect the consistency and amount of saliva produced by our salivary glands,” said Dr. Chris Thompson, a board-certified otolaryngologist with Providence Mission Hospital in Orange County, California.
The following saliva changes might warrant a medical consult.
You’re running low on spit.
Xerostomia, or dry mouth, is very common and can happen for quite a few reasons — usually, it’s a sign of dehydration or a side effect of certain medications.
“A number of commonly used medications affect saliva production and secretion and lead to dry mouth,” Glessing said. “These include blood pressure medications, diuretics, antidepressants, antihistamines, as well as some pain and anxiety medications.”
Too little saliva and dry mouth can also be caused by an autoimmune condition called Sjogren’s syndrome. “It’s a chronic multisystem inflammatory disorder that affects the lacrimal and salivary glands,” Glessing said, resulting in dry eyes and mouth, respectively.
Diabetes is another common medical condition associated with dry mouth. “It’s thought that increased glucose (sugar) causes an imbalance in the saliva make-up, and the diabetes itself causes a reduction in salivary gland function,” Glessing said.
You’ve become a drool fiend.
On the flip side, excess saliva could be a sneaky sign of acid reflux or gastroesophageal reflux disease (GERD) called “water brash,” according to the International Foundation for Gastrointestinal Disorders. It’s a sudden rush of saliva that strikes when stomach acid and saliva are regurgitated up into your mouth.
It can also be a side effect of being pregnant, known as ptyalism gravidarum. Why it happens is unclear, but it’s thought to be linked to hormonal changes, such as hCG production (a hormone produced by the placenta) and high estrogen levels. The perma-nausea that can strike during pregnancy is another possible trigger.
But the most common reason for the feeling of too much saliva is a decrease in the swallowing (or clearance) of a normal amount of saliva.
“Many factors may lead to swallowing difficulty, but this typically doesn’t mean the saliva glands are producing too much fluid,” said Dr. Abie Mendelsohn, a laryngologist at the Los Angeles Center for Ear, Nose, Throat and Allergy. Usually, it’s an issue seen in people with neurologic diseases. It’s always best to check with a doctor if something is different or off.
There’s blood in your saliva.
Bloody saliva’s usually the result of an injury to the mouth or gumline — say, from getting too aggressive with your toothbrush. Poor dental hygiene and gingivitis (gum inflammation) are the most common causes of blood in the saliva. Runners-up: canker sores and oral ulcers.
“Oral ulcers may be incidental, but could be caused by other more systemic illnesses, such as Crohn’s disease or coeliac disease,” Glessing said. “Diets low in vitamin B12, folic acid, iron or zinc may also lead to mucosal injury in the mouth and blood in the saliva.”
It tastes sour or metallic.
Saliva that tastes sour or metallic can be a sign of acid reflux or GERD, which causes stomach acid to flow back up into your throat, creating a bitter or sour taste once it mixes with your spit.
Sour or metallic tastes are especially common when you’re pregnant, Glessing said, thanks to the hormonal shifts combined with the perpetual nausea and vomiting. (Fortunately, your taste buds will likely go back toward normal after the first trimester, according to the Cleveland Clinic.)
Another culprit is hay fever. On top of the itchy eyes, runny nose and sneezing, the inflamed nasal passages and problems smelling food can trigger a metallic taste in your mouth.
“Vitamin B12 deficiency is also a common cause of metallic taste due to its effect on the central nervous system,” Glessing said.
On the more serious side of the spectrum, people with kidney and liver problems can experience a metallic taste in their mouth “due to the accumulation of waste materials in the blood and body secretions, including saliva,” Glessing added.
There’s a perma-sweet taste in your mouth
Sweet-tasting saliva can be a sign of uncontrolled diabetes, where high blood sugar levels cause an uptick in glucose being secreted in your spit.
Bacterial or viral infections of the upper respiratory tract may leave a sweet taste in your mouth by interfering with the way your brain reacts to sweet, bitter, sour and salty tastes, Glessing said. The infection itself can also cause saliva to have more glucose in it than normal, though this usually goes away once the infection is treated.
Damaged sensory taste nerves can leave you with a constant sweet taste in your mouth as well — say, because of a past COVID-19 infection, stroke or seizure heightening or impairing your sense of taste.
Your saliva’s become white and sticky.
If your saliva’s consistency is on the tacky side and it looks like you dipped your tongue in white paint, it could be a one-two punch of dehydration and dry mouth: Debris, bacteria and dead cells get stuck between the bumps on your tongue, giving the appearance of a white coating, according to the Mayo Clinic.
Or, it could be an oral infection. The candida albicans fungus can cause thrush — a yeast overgrowth in your mouth, Thompson said.
People with diabetes are especially vulnerable, since sugars in your saliva can lead to yeast growth. Certain medications, like antibiotics and inhaled corticosteroids, can also disrupt the balance of microorganisms in your body and increase your risk of thrush.
It’s thick and stringy.
“Changes in consistency, to where your saliva becomes thick and stringy, is usually due to an imbalance of the water and other constituents of the saliva,” Glessing said.
This could indicate that you’re a mouth breather — say, as a result of a stuffy nose, deviated septum or obstructive sleep apnea. The drying effect of breathing through your mouth at night can cause what’s left of your saliva the next morning to feel especially gooey.