Will Saliva make food go bad

Will Saliva make food go bad

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My mom was telling me that if I put the unfinished bowl of milk and cereal back to the fridge, the saliva that has been stuck to the spoon gets passed to the milk. The saliva in milk will make milk go bad faster than if there were no saliva inside. Is that true? If so, how comes? It would be great if there are scientific evidences or references to back it up.

I have found a Quora post having some people saying that it will make the food go bad faster. I was not able to find any other references

Packaging that knows when food is going bad

Packaging that alerts consumers to food which is starting to go bad is being developed by researchers at the University of Strathclyde in Glasgow.

The project aims to improve food safety and cut unnecessary food waste by developing a new type of indicator, made of 'intelligent plastics' which give a warning, by changing colour, of when food is about to lose its freshness because it has broken or damaged packaging, has exceeded its 'best before' date or has been poorly refrigerated.

An estimated 8.3 million tonnes of household food- most of which could have been eaten- is wasted in the UK each year.

The indicator is to be used as part of a form of food packaging known as modified atmosphere packaging, which keeps food in specially-created conditions that prolong its shelf life.

Freshness indicators typically take the form of labels inserted in a package but these come at a significant cost. Strathclyde researchers are looking to create a new type of indicator which is an integral part of the packaging, and so is far less expensive. The project has received £325,000 in support from the Scottish Enterprise Proof of Concept Programme.

Professor Andrew Mills, who is currently leading the Strathclyde project, said: "At the moment, we throw out far too much food, which is environmentally and economically damaging.

"Modified atmosphere packaging is being used increasingly to contain the growth of organisms which spoil food but the costs of the labels currently used with it are substantial. We are aiming to eliminate this cost with new plastics for the packaging industry.

"We hope that this will reduce the risk of people eating food which is no longer fit for consumption and help prevent unnecessary waste of food. We also hope it will have a direct and positive impact on the meat and seafood industries."

By giving a clear and unambiguous sign that food is beginning to perish, the indicators being developed at Strathclyde could resolve potential confusion about the different significances of 'best before' dates and 'sell-by' dates. They could also help to highlight the need for food to be stored in refrigerators which are properly sealed.

Lisa Branter, acting head of the Proof of Concept Programme, said: "Through the Proof of Concept Programme, we are creating the opportunities to build high value, commercially viable spin-out companies from ground-breaking research ideas. What we want to achieve are more companies of scale created as a result of the Programme, and this project is a great example of an idea which offers real business opportunities."

Story Source:

Materials provided by University of Strathclyde. Note: Content may be edited for style and length.

Dry Mouth? Don't Delay Treatment

Three glands (salivary glands) produce saliva, which drains through tubes (salivary ducts) to irrigate the mouth. When the glands do not make enough saliva, the mouth becomes dry.

Almost everyone’s mouth is dry sometimes. But if you feel like you have cotton in your mouth constantly, it may be time for treatment.

Dry mouth, known medically as xerostomia, occurs when you don’t have enough saliva, or spit, in your mouth.

Feeling stressed can trigger dry mouth temporarily. But a persistently dry mouth may signal an underlying disease or condition, so it’s important to see your doctor, says the Food and Drug Administration (FDA), which regulates products that relieve dry mouth.

And because dry mouth can lead to tooth decay, you should see your dentist, too, says John V. Kelsey, D.D.S., of FDA’s Division of Dermatology and Dental Products.

Dry mouth may make it difficult to speak, chew, and swallow, and may alter the taste of your food. It can also cause a sore throat, hoarseness, and bad breath.

Dry mouth can affect people of any age, but older people are especially vulnerable. “It’s not a normal consequence of aging,” says Kelsey. “Older people may take multiple medications that can cause dry mouth.”

According to the Surgeon General's Report on Oral Health in America, dry mouth is a side effect of more than 400 prescription and over-the-counter drugs, such as antidepressants, antihistamines, muscle relaxants, and high blood pressure medicines.

Other causes of dry mouth include:

  • cancer treatments, such as chemotherapy and radiation of the head or neck
  • hormone changes, such as those that occur during pregnancy or menopause
  • health problems, such as HIV/AIDS, diabetes, and Sjögren’s syndrome, a disease in which a person’s immune system attacks the body’s tissues, including moisture-producing glands
  • snoring or breathing open-mouthed

The Role of Saliva

Saliva is produced by three major glands in the mouth (salivary glands) and plays a key role in

  • chewing, swallowing, and digesting food
  • preventing infection in the mouth by controlling bacteria
  • preventing tooth decay

“Saliva is mostly water, but it also contains enzymes and lubricants,” says Kelsey. “The enzymes help digest food and the lubricants make speaking, chewing, and swallowing more comfortable.”

Saliva helps control bacteria, which cling to the surface of teeth. They feed on sugar in the food we eat and break down and use (metabolize) the sugar to grow.

“A by-product of the metabolized sugar is acid, which starts to eat away at a tooth’s surface,” says Kelsey. Saliva neutralizes the acid and helps wash away food particles. If there is not enough saliva, cavities may occur.

Dry Mouth Treatments

Your doctor or dentist may recommend oral rinses and moisturizers, or prescribe an artificial saliva.

Also called saliva substitutes, artificial salivas are regulated by FDA as medical devices. “Unlike drugs, artificial salivas have no chemical action,” says Susan Runner, D.D.S., chief of FDA’s dental devices branch. “Their action is mechanical. They moisten and lubricate the mouth but do not stimulate the salivary glands to make saliva.”

While not a cure, artificial salivas can provide short-term relief of the symptoms of dry mouth. “They can also help minimize discomfort after an oral procedure,” says Runner.

Artificial salivas come in a variety of forms, including rinses, sprays, swabs, gels, and tablets that dissolve in the mouth. Some are available by prescription only others can be bought over-the-counter.

FDA has also approved several prescription drugs to relieve dry mouth caused by certain medical treatments or conditions, such as Sjögren's syndrome and radiation for head or neck cancer.

University at Buffalo researcher examines role of little-studied IgM in Sjögren&rsquos syndrome

By Marcene Robinson

Release Date: January 13, 2016

BUFFALO, N.Y. &ndash For years, researchers believed IgM, a protective type of antibody, played an insignificant role in Sjögren&rsquos syndrome.

However, new research, led by University at Buffalo oral biology researcher Jill Kramer, aims to re-examine whether this seemingly harmless antibody is pathogenic, or capable of causing disease.

The results may lead to a better understanding of IgM&rsquos effect on Sjögren&rsquos syndrome &ndash an incurable autoimmune disorder that affects more than 1 million Americans, 90 percent of whom are women &ndash and other autoimmune diseases, such as lupus and rheumatoid arthritis.

The research, &ldquoAnalysis of the Source and Significance of IgM in Sjögren&rsquos syndrome,&rdquo is one of several studies funded through a $16 million Clinical and Translational Science Award provided to UB from the National Institutes of Health to quicken the delivery of new drugs, diagnostics and medical devices to patients.

&ldquoThe best patient care goes hand-in-hand with clinical research,&rdquo says Timothy Murphy, MD, principal investigator, SUNY Distinguished Professor of Medicine, and senior associate dean for clinical and translational research in the Jacobs School of Medicine and Biomedical Sciences.

&ldquoDr. Kramer&rsquos study will use novel approaches to identify the type of autoantibodies responsible for Sjögren&rsquos syndrome and is critical in guiding the development of better therapies for this disease.&rdquo

Sjögren&rsquos syndrome is an autoimmune disorder in which the body&rsquos white blood cells attack healthy cells that produce saliva and tears. The disorder is characterized by dryness of the eyes and mouth, placing patients at a high risk for tooth decay and other oral health complications.

&ldquoPatients with Sjögren&rsquos syndrome are more prone to dental problems, and often experience difficulty in talking and swallowing food,&rdquo says Kramer, DDS, PhD, assistant professor in the Department of Oral Biology in the UB School of Dental Medicine. &ldquoIt is important we understand why the disease occurs and develop new ways to prevent the immune system from attacking healthy tissues.&rdquo

Using mice that lack the ability to produce their own antibodies, Kramer will administer IgM from mice with Sjögren&rsquos syndrome and examine whether the rodents develop symptoms related to the disease, a sign that the class of antibody may be pathogenic. A separate set of mice will receive IgG, another type of antibody that is harmful in many autoimmune diseases, including Sjögren&rsquos syndrome.

While IgG is produced primarily to attack bacteria and other pathogens, IgM functions as the body&rsquos garbage man, helping to clean up cellular debris and reduce inflammation before a stronger response with IgG is triggered, says Kramer.

Because of IgG&rsquos harmful nature in autoimmunity, more Sjögren&rsquos syndrome-related research exists on this antibody class than its weaker counterpart. But after recent studies found that those diagnosed with the disorder produce a high amount of IgM, Kramer speculated that the antibody plays a greater role than previously thought.

By testing how IgM effects salivary function in mice, Kramer can learn whether the antibody is harmful or released as part of a protective measure, which could aid the development of medicine and other treatments.

Additional contributors to the project include co-investigator Daniel Gaile, PhD, assistant professor in the Department of Biostatistics in the School of Public Health and Health Professions, and Liam McCabe, a research technician in the School of Dental Medicine.

Salivary stones - How to detect, treat, and prevent

Formation of salivary stones, a condition medically called Sialolithiasis, occurs when bacterial staph infections, chronic dehydration or excessive amounts of calcium exist in the body that inhibit salivary gland functioning. When saliva becomes abnormally thick, (due to disorders such as Sjogren's syndrome, upper respiratory diseases that irritate or swell nasal passages and ingestion of medications that dry moist oral and nasal tissues) calcification of saliva precipitates within salivary ducts and glands that enlarge and eventually block saliva flow.

Most salivary stones affect glands lying at the bottom of the mouth called the submandibular glands. However, stones can also impair functioning of the parotid glands and the sublingual glands found underneath the tongue.

Symptoms of Salivary Stones

People suffering from salivary stones may not experience any symptoms until the stones grow large enough to block ducts. When this occurs, saliva released by the gland has nowhere to go and backs up in the gland, causing swelling, pain and sometimes a low grade fever. In addition, any activity that increases salivary production such as eating or smelling something cooking can exacerbate swelling and pain.

Other symptoms may include:

  1. Saliva that tastes odd, gritty or bitter
  2. Severe halitosis caused by dry mouth and infected salivary glands
  3. Difficulty opening and closing the mouth

If not treated in a timely manner, salivary stone obstruction may lead to a serious bacterial infection that requires intravenous administration of antibiotics and/or surgical drainage of blocked glands. Moreover, conditions conducive to salivary stone formation such as dry mouth, chronic sinusitis and allergies promote the rapid development of anaerobic bacteria. These microorganisms are primarily responsible for halitosis, tooth decay, gum disease and even tonsil stones.

Tonsil stones should not be confused with saliva stones. While tonsil stones and saliva stones resemble each other in composition, tonsil stones form within the fissures of the tonsils and do not generally cause medical issues if left untreated. The main problem produced by tonsil stones is serious halitosis that can be extremely embarrassing to the person suffering from them.

Detection and Removal of Salivary Stones

Physicians detect salivary stones via CT scans, X-rays or ultrasounds in addition to performing a physical examination on patients suspected of having salivary stones. Removal may be as easy as deliberately stimulating saliva flow (sucking on a lemon or orange slice, for example) while a physician manually massages the affected gland in order to pass the stone spontaneously. Alternately, larger stones may need minor surgery to fully extricate them. This involves an oral surgeon making a small incision near the affected duct and removing stones responsible for obstructing saliva flow.

Side effects may occur when surgery is performed to remove salivary stones. Eventual, extensive scarring of salivary ducts could result in partial or complete failure of the salivary gland to function normally, causing a chronic condition of dry mouth due to lack of sufficient saliva amounts. If the gland affected by saliva stones is the submandibular gland and surgery is needed to remove stones, there is a possibility that two important facial nerves could be injured during the procedure. Damage to the hypoglossal nerve could numb portions of the tongue while damage to the primary facial nerve may induce partial or complete paralysis of the face.

For people who continuously suffer chronic reformations of salivary stones or suffer irreparable damage to one or more salivary glands, physicians will usually recommend removal of the disabled gland to eliminate the potential for serious bacterial infections.

Preventing Formation of Salivary Stones

Unless someone has a disorder or disease specific to salivary glands, maintaining a sufficient flow of saliva is the best way to prevent the formation of salivary stones. Proper mouth hydration is also vital to preventing tooth decay, gum disease and halitosis, since anaerobic bacteria are directly responsible for these problems. Anaerobic bacteria thrive in dry, airless, stagnant oral conditions by consuming mouth debris, mucus and dead tissue that saliva normally washes away. A chronically dry mouth is highly conducive to anaerobic bacterial growth, which is also a factor contributing to the formation of salivary stones.

To keep the mouth sufficiently hydrated, clean-smelling and free of destructive oral bacteria, TheraBreath's powerfully effective line of toothpastes, rinses, gargles, mints and chewing gum provides your mouth with ingredients that naturally promote saliva flow, inhibits saliva stone formation and kills anaerobic bacteria. Bacteriologist, dentist and creator of TheraBreath, Dr. Harold Katz, has included a special ingredient he had patented called OXYD-8. Click here to view a complete line of TheraBreath® products.

OXYD-8 is an oxygenating compound that not only stimulates saliva flow but also converts gases comprising bad breath odor into odorless, tasteless molecules that leave your breath fresh and your teeth feeling clean. Additionally, maintaining a consistently moist mouth helps prevent saliva from becoming thick and glutinous, a condition that directly contributes to blockage of salivary gland ducts by salivary stones.

Regular use of TheraBreath's specially formulated oxygenating oral hygiene products containing OXYD-8 can effectively prevent the development of potentially serious oral diseases caused by a chronically dry mouth such as salivary stones, gum disease, cavities and substantial tooth loss.


Bacteria need moisture, oxygen and the proper temperature range in order to multiply. Dehydration is the process of removing moisture from foods, thereby slowing or stopping the growth of spoilage bacteria. To dehydrate food properly, you need low humidity and a source of heat. You can use a conventional oven set to warm with the door open or an actual food dehydrator. The food needs to be heated to about 140 F. Dry, circulating air helps draw moisture out of the food. Dehydration also makes foods lighter, smaller and easier to store and transport.

Cool Jobs: Saliva offers a spitting image of our health

Lots of saliva helps contestants get good distance at Purdue University’s annual cricket-spitting contest in West Lafayette, Ind.

Rebecca McElhoe/Purdue University

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Purdue University has again canceled its annual cricket-spitting contest. It’s not safe yet, due to the coronavirus pandemic. If it resumes in 2022, though, insects again will be far from the only thing flying through the air. Lots of spit will spray out, too.

“Getting saliva on the cricket makes it more aerodynamic,” notes Thomas Turpin. He’s the retired insect scientist who started the contest 25 years ago at Purdue’s campus in West Lafayette, Ind. The goal: Spit a partially frozen cricket as far as you can.

No one at Purdue has analyzed the cricket contestants’ spit. But it’s probably more watery than the saliva in your mouth when you rest or drool, says Lissa Davis. It also would have flowed faster from the saliva glands. It might host a different mix of proteins as well. Davis is a graduate student at the university’s SPIT Lab. Food scientist Cordelia Running heads this lab, whose acronym stands for Saliva, Perception, Ingestion and Tongue.

Even psychology can affect how much spit your mouth makes. Several years ago, Running and a colleague learned that people spat out more of a test liquid if they thought it was an extract of rabbit hair instead of tea. That’s not necessarily the case for cricket spitting. “But if people were grossed out by having a cricket in their mouth, they might have tried harder to spit it out,” Davis says.

Saliva seeps and swishes around our mouths all the time. Most of us don’t give it much thought. But a growing cadre of scientists sees saliva as a font for important research. Their recent findings have been shedding light on how saliva is made, how it interacts with our sense of taste and how it can help diagnose when things go wrong inside us.

Drool is saliva that drips outside the mouth. It’s mostly water, but also has a variety of other chemicals. Saliva protects our teeth, guards against infection, helps with healing and more. Kuramyndra/iStock/Getty Images Plus

What’s in saliva?

The average adult produces about a liter (1.1 quarts) of saliva per day. Over a lifetime, that “compares to about the size of a tank truck,” says Stefan Ruhl. We’re talking about some 26,500 liters (7,000 gallons), a volume that would fit into a typical U.S. milk tanker trailer.) Ruhl is a dentist and oral biologist who works at the University at Buffalo in New York.

Saliva production is highest during the day, especially at mealtimes. About 99 percent of that goo is water. The rest is mostly proteins and salts. Most of our spit comes from three major pairs of salivary glands: one pair under the tongue, another pair beneath the jaw and a third pair near the back of the jaw and in front of the ears. Many minor glands secrete saliva, too. Tissues lining our mouth and the plasma in our blood add tiny amounts of material to all that saliva. The plasma gets in where teeth jut out at the gums, Ruhl explains.

Arrows in this CT-scan image point to normal-looking parotid glands. They’re one of our three major pairs of saliva glands. They sit near the back of the jaw and close to the ears. R. Rastogi et al/Indian Journal of Radiology and Imaging 2012 (CC BY-NC-SA 3.0)

He and others recently showed where the saliva glands get some of the major proteins they put into human saliva. This work offers clues to the role of certain genes. After all, genes tell cells which proteins to make and when. Details about their roles are coded into parts of our DNA. This study also paves the way for more investigations into how saliva evolved in humans and other species.

Saliva’s water and other chemicals have many roles. For one, saliva acts like a gatekeeper. “It keeps the bad stuff out,” Ruhl says, and “lets the good stuff in.” Some chemicals in our spit help with healing and protect against infection. And by acting like a buffer, or shield, saliva protects teeth from too much acidity.

Saliva also provides a moist home for our mouths’ microbiome (MY-kroh-BY-ohm). That’s the group of bacteria and other organisms that live there. Most are harmless, although some bacteria do cause cavities and other problems. In fact, good microbes can crowd out more dangerous ones, such as fungi, Ruhl notes.

Finally, saliva helps us eat. As our mouths water, saliva not only softens and shapes food into wads but also helps us swallow them. That’s thanks to mucins (MYOO-sins), Ruhl says. These long strings of amino acids have sugars jutting out from them, like bristles sticking out from a bottle brush or mascara brush. Mucins reduce friction, making food slippery enough for us to swallow. Mucins also help keep in moisture. That keeps tissues in our mouths from drying out.

Then there’s amylase (AM-ih-lace), an enzyme in saliva. It helps break down the starches we eat. Starches start out as long chains whose links consist of sugars. Amylase helps cut those chains into pieces. Without this, Ruhl explains, “you would chew on a piece of bread, but you would not taste the sweetness.” That enzyme may also send signals down to the gut, he notes, telling it to get ready for incoming starches that will need to be digested.

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Chocolate milk and more

Research at Purdue’s SPIT Lab looks more closely at how saliva affects our taste experience. Saliva “mixes with food when you eat it,” Davis points out. Chemicals in that saliva may react with our meal. Research about these interactions could help scientists figure out ways to help people choose healthier foods.

Explainer: Taste and flavor are not the same

For example, many people avoid vegetables that taste bitter. That’s especially true for young children, Davis says. Some poisonous plants are bitter, she notes, so we may have evolved receptors in the mouth to alert us to bitter compounds so that we can avoid potential poisons. Genetics could play a role as well.

One group of chemicals that activates our tongues’ bitter-taste receptors are polyphenols (PAHL-ee-FEE-nuhls). They’re in broccoli, spinach and some other vegetables. They also show up in beer, wine, coffee and chocolate. SPIT Lab researchers want to know how saliva may affect the way we perceive foods rich in these compounds. They wondered if there might be ways to change those taste sensations over time.

In one study, people drank different beverages for much of a month. During one week they drank three glasses each day of almond-based chocolate milk. Another week the drink was made with cow’s milk. On a third week, they drank no chocolate milk at all. After each week, these people provided samples of their saliva. An analysis showed significant changes in the relative share of 96 proteins in that spit.

Red and green fluorescence in this microscopy image show the presence of different proteins in a saliva gland. The cells’ nuclei show up as grey. A greenish hue marks membrane cells around areas that collect saliva from the cells that secrete it. Alison May

This suggests our bodies change the recipe of proteins in our saliva in response to what we regularly eat or drink. Says Davis, “It would make sense that your body would kind of adjust to make that sensation more pleasant for you.”

Together with SPIT Lab researcher Ciera Crawford, Running shared these findings last October in Physiology & Behavior.

Their data don’t show how much the protein changes might alter what foods taste like. In fact, people reported little change during the study in their sense of the milk’s flavor. However, many people already liked chocolate milk. In contrast, Davis had trouble recruiting volunteers for a related study. Those people would have been drinking “bad versions of tea” for a month.

SPIT Lab researchers hope to focus more closely on the role of certain proteins in saliva. Also, Davis adds, “not every vegetable is inherently bitter.” She hopes to zero in on how saliva may interact with other types of compounds in foods, including ones with “an element of gross.”

Spit can even help diagnose disease

Sure, we’ve all heard of saliva tests to sample for DNA, and even sometimes COVID-19. But such tests are now expanding into brain injuries, such as concussion. Its symptoms can include headaches, nausea, double vision and dizziness. A patient may also have problems with memory, concentration or sleep. Sometimes symptoms do not show up right away. What’s more, children and teens don’t always report symptoms accurately. Better detection could help with treatment and make sure patients get time to heal.

Simpler, easier COVID-19 test developed with kids in mind

Steven Hicks is a pediatrician at Pennsylvania State College of Medicine in Hershey. He notes that when a concussion occurs, levels of certain signaling molecules in the nervous system may change. Known as micro-RNAs, or miRNAs, they tell cells to make or stop making proteins for different jobs. Hicks was part of a team that analyzed some of these miRNAs that are released into saliva by cranial nerves in the head.

This study analyzed saliva from 538 people. Most were under 25 years old. The researchers knew which people had sustained a concussion. They used data from the first 400 or so to create a computer model. It helped the team know which types of miRNA were more likely to be in the saliva of patients who had sustained a concussion.

The computer model then used machine learning to look for four telltale miRNAs. “We tested that model in a whole different set of 150 adolescents,” Hicks says. The results compared well with doctors’ diagnoses made without the model.

Saliva tests probably won’t replace current concussion analyses in children and adults, Hicks says. These include brain scans, blood tests and watching for symptoms. The team’s test could, however, help as an additional screening tool. It might also help diagnose concussions in people who are unconscious.

The team described its findings last October in the International Journal of Molecular Sciences.

Parents have told Hicks they really appreciate when he doesn’t have to stick needles in their kids’ arms. Several years ago he wanted to do a study on autism. This family of disorders affects how the brain develops. Only one parent would let Hicks’ team draw a child’s blood for research. So the team looked into saliva as an alternative.

Genetic factors seem to play a large role in autism. Studies also suggest that the gut’s microbiome could be involved. Hicks and others used saliva to test the mouth’s microbiome. They found that this community of microbes in 346 young children with autism differed from that in children without autism. If such oral testing could lead to earlier diagnoses, affected children can get help sooner. Hicks’ group reported its findings three years ago in Autism Research.

Levels of uric acid in saliva samples can indicate a teen’s percentage of body fat, Brazilian researchers find. Their work could help identify teens at risk for diseases linked to excessive body fat. Paula Midori Castelo/UNIFESP

Other recent studies suggest saliva can help screen for marijuana use or help diagnose type 1 diabetes. And Brazilian scientists showed how uric acid in saliva can help estimate the build-up of body fat in teens. Our bodies produce the acid as it digests certain foods. That study appeared in the February 2020 Nutrition Research.

Saliva can even help scientists gauge anxiety, notes Nattinee Jantaratnotai. She works at Mahidol University in Bangkok, Thailand. There, she studies the effects of medicines and other compounds. Levels of the enzyme amylase rise during periods of stress, she says. The same goes for cortisol, a hormone behind the body’s fight-or-flight reaction. So “we can use amylase and cortisol as representatives of stress,” she says. And in contrast to drawing blood, “saliva collection is non-invasive and convenient.”

She and others measured levels of both those chemicals in the saliva of dental patients. They also took people’s blood pressure and pulse. Stress levels were lower overall when people were exposed to the scent of roasted coffee while their teeth were being cleaned. This was in contrast to when dental patients were breathing unscented air. And it didn’t seem to matter if these people normally drank coffee or not. The researchers think the result was due to chemicals in the coffee’s aroma. However, they point out, it was not a double-blind study because people knew when they smelled the coffee.

Scientists have only begun to delve into what most of saliva’s many ingredients do. A “really challenging” aspect of spit science, Davis admits, is that “everything seems to matter.” So much of what we do and experience can affect what goes on in our mouths,” she says, and “potentially influence what’s in saliva.”

That’s why studying this body fluid is nothing to spit at.

Power Words

activate: (in biology) To turn on, as with a gene or chemical reaction.

amino acids: Simple molecules that occur naturally in plant and animal tissues and that are the basic building blocks of proteins.

amylase: An enzyme that breaks starches down into the sugars from which they had been made.

annual: Adjective for something that happens every year. (in botany) A plant that lives only one year, so it usually has a showy flower and produces many seeds.

anxiety: A nervous reaction to events causing excessive uneasiness and apprehension. People with anxiety may even develop panic attacks.

autism: (also known as autism spectrum disorders ) A set of developmental disorders that interfere with how certain parts of the brain develop. Affected regions of the brain control how people behave, interact and communicate with others and the world around them. Autism disorders can range from very mild to very severe. And even a fairly mild form can limit an individual’s ability to interact socially or communicate effectively.

average: (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.

behavior: The way something, often a person or other organism, acts towards others, or conducts itself.

biologist: A scientist involved in the study of living things.

blood pressure: The force exerted against vessel walls by blood moving through the body. Usually this pressure refers to blood moving specifically through the body’s arteries. That pressure allows blood to circulate to our heads and keeps the fluid moving so that it can deliver oxygen to all tissues. Blood pressure can vary based on physical activity and the body’s position. High blood pressure can put someone at risk for heart attacks or stroke. Low blood pressure may leave people dizzy, or faint, as the pressure becomes too low to supply enough blood to the brain.

brain scan: A technique to view structures inside the brain, typically with X-rays or a magnetic resonance imaging (or MRI) machine. With MRI technology — especially the type known as functional MRI (or fMRI) — the activity of different brain regions can be viewed during an event, such as viewing pictures, computing sums or listening to music.

cell: The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

colleague: Someone who works with another a co-worker or team member.

compound: (often used as a synonym for chemical) A compound is a substance formed when two or more chemical elements unite (bond) in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O.

computer model: A program that runs on a computer that creates a model, or simulation, of a real-world feature, phenomenon or event.

concentration: (in chemistry) A measurement of how much of one substance has been dissolved into another.

concussion: Temporary unconsciousness, or headache, dizziness or forgetfulness due to a severe blow to the head.

coronavirus: A family of viruses named for the crown-like spikes on their surface (corona means “crown” in Latin). Coronaviruses cause the common cold. The family also includes viruses that cause far more serious infections, including SARS.

cortisol: Also known as hydrocortisone, this is a hormone produced by the adrenal glands. It can serve as the body’s main warning that it is under stress. It helps regulate a wide range of body functions, including how we process the energy in food, create memories and control inflammation.

cranial nerves: A set of 12 pairs of nerves in mammals that connects the brain directly to muscles and organs of the head and torso.

dental: (adj.) Meaning related to teeth.

develop: (in biology) To grow as an organism from conception through adulthood, often undergoing changes in chemistry, size, mental maturity or sometimes even shape. grasslands are cut down and replaced with structures or landscaped yards and parks.

diabetes: A disease where the body either makes too little of the hormone insulin (known as type 1 disease) or ignores the presence of too much insulin when it is present (known as type 2 diabetes).

diagnose: To analyze clues or symptoms in the search for their cause. The conclusion usually results in a diagnosis — identification of the causal problem or disease.

digest: (noun: digestion) To break down food into simple compounds that the body can absorb and use for growth. Some sewage-treatment plants harness microbes to digest — or degrade — wastes so that the breakdown products can be recycled for use elsewhere in the environment.

disorder: (in medicine) A condition where the body does not work appropriately, leading to what might be viewed as an illness. This term can sometimes be used interchangeably with disease.

DNA: (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

double-blind study: A study in which neither the participants nor their doctors (or other people administering the study) know who is receiving a potentially therapeutic treatment.

element: A building block of some larger structure.

extract: (v.) To separate one chemical (or component of something) from a complex mix. (noun) A substance, often in concentrated form, that has been removed from its natural source.

factor: Something that plays a role in a particular condition or event a contributor.

flavor: The particular mix of sensations that help people recognize something that has passed through the mouth. This is based largely on how a food or drink is sensed by cells in the mouth. It also can be influenced, to some extent, by its smell, look or texture.

friction: The resistance that one surface or object encounters when moving over or through another material (such as a fluid or a gas). Friction generally causes a heating, which can damage a surface of some material as it rubs against another.

gauge: A device to measure the size or volume of something. For instance, tide gauges track the ever-changing height of coastal water levels throughout the day. Or any system or event that can be used to estimate the size or magnitude of something else. (v. to gauge) The act of measuring or estimating the size of something.

gene: (adj. genetic) A segment of DNA that codes, or holds instructions, for a cell’s production of a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

genetic: Having to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

gland: A cell, a group of cells or an organ that produces and discharges a substance (or “secretion”) for use elsewhere in the body or in a body cavity, or for elimination from the body.

gut: An informal term for the gastrointestinal tract, especially the intestines.

hormone: (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body.

host: (v.) The act of providing a home or environment for something.

infection: A disease that can spread from one organism to another. It’s usually caused by some type of germ.

insect: A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.

link: A connection between two people or things.

machine learning: A technique in computer science that allows computers to learn from examples or experience. Machine learning is the basis of some forms of artificial intelligence (AI). For instance, a machine-learning system might compare X-rays of lung tissue in people with cancer and then compare these to whether and how long a patient survived after being given a particular treatment. In future, that AI system might be able to look at a new patient’s lung scans and predict how well they will respond to a treatment.

marijuana: A mind-altering drug. It is made from the leaves (and sometimes stems or seeds) of the Cannabis sativa plant. This drug also goes by the colloquial terms pot and weed.

microbe: Short for microorganism. A living thing that is too small to see with the unaided eye, including bacteria, some fungi and many other organisms such as amoebas. Most consist of a single cell.

microbiome: The scientific term for the entirety of the microorganisms — bacteria, viruses, fungi and more — that take up permanent residence within the body of a human or other animal.

microRNA, or miRNA: A type of messenger chemical that helps cells do a job. It tells cells to make or stop making proteins.

model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.

nausea: The feeling of being sick to one's stomach, as though one could vomit.

nerve: A long, delicate fiber that transmits signals across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

nervous system: The network of nerve cells and fibers that transmits signals between parts of the body.

oral: An adjective that refers to things in or affecting the mouth.

organism: Any living thing, from elephants and plants to bacteria and other types of single-celled life.

pandemic: An epidemic that affects a large proportion of the population across a country or the world.

pediatrician: A doctor who works in the field of medicine that has to do with children and especially child health.

perception: The state of being aware of something — or the process of becoming aware of something — through use of the senses.

physiology: The branch of biology that deals with the everyday functions of living organisms and how their parts function. Scientists who work in this field are known as physiologists.

plasma: (in medicine) The colorless fluid part of blood.

protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues they also do the work inside of cells. Among the better-known, stand-alone proteins are the hemoglobin (in blood) and the antibodies (also in blood) that attempt to fight infections. Medicines frequently work by latching onto proteins.

psychology: (adj. psychological ) The study of the human mind, especially in relation to actions and behavior. To do this, some perform research using animals. Scientists and mental-health professionals who work in this field are known as psychologists.

receptor: (in biology) A molecule in cells that serves as a docking station for another molecule. That second molecule can turn on some special activity by the cell.

salivary glands: These organs make saliva that moves through ducts into the mouth. Saliva helps animals swallow and chew their food.

salt: A compound made by combining an acid with a base (in a reaction that also creates water). The ocean contains many different salts — collectively called “sea salt.” Common table salt is a made of sodium and chlorine.

screening: A health test that is done early, before any symptoms are present. That can help find disease when it is easiest to treat. Screenings can include blood tests (such as for HIV, diabetes or high cholesterol), X-rays or scans (such as mammograms for breast cancer).

secrete: (noun: secretion) The natural release of some liquid substance — such as hormones, an oil or saliva — often by an organ of the body.

signaling molecule: A substance created by an organism and released into the environment. In organisms that use quorum sensing, signaling molecules are used to broadcast an individual’s presence to similar organisms nearby.

species: A group of similar organisms capable of producing offspring that can survive and reproduce.

starch: A soft white chemical made by all green plants. It’s a relatively long molecule made from linking together a lot of smaller, identical building blocks — all of them glucose, a simple sugar. Plants and animals use glucose as an energy source. Plants store that glucose, in the form of starch, as a reserve supply of energy. Animals that consume starch can break down the starch into glucose molecules to extract the useful energy.

stress: (in biology) A factor — such as unusual temperatures, movements, moisture or pollution — that affects the health of a species or ecosystem. (in psychology) A mental, physical, emotional or behavioral reaction to an event or circumstance (stressor) that disturbs a person or animal’s usual state of being or places increased demands on a person or animal psychological stress can be either positive or negative.

symptom: A physical or mental indicator generally regarded to be characteristic of a disease. Sometimes a single symptom — especially a general one, such as fever or pain — can be a sign of any of many different types of injury or disease.

taste: One of the basic properties the body uses to sense its environment, especially foods, using receptors (taste buds) on the tongue (and some other organs).

tissue: Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.


Journal: P. Pachimsawat, K. Tangprasert and N. Jantaratnotai. The calming effect of roasted coffee aroma in patients undergoing dental procedures. Scientific Reports. Vol. 11, January 14, 2021. doi: 10.1038/s41598-020-80910-0.

Journal: M. Saitou et al. Functional specialization of human salivary glands and origins of proteins intrinsic to human saliva. Cell Reports. Vol. 33, November 17, 2020, p. 108402. doi: 10.1016/j.celrep.2020.108402.

Journal: S. Hicks et al. Saliva microRNA biomarkers of cumulative concussion. International Journal of Molecular Sciences. Vol. 21, October 20, 2020. doi: 10.3390/ijms21207758.

Journal: C. Crawford and C. Running. Addition of chocolate milk to diet corresponds to protein concentration changes in human saliva. Physiology & Behavior. Vol. 225, October 15, 2020, p. 113080. doi: 10.1016/j.physbeh.2020.113080.

Meeting: S. Prasad et al. Rapid response electrochemical biosensor for detecting THC in saliva American Chemical Society. Spring 2020 National Meeting. Submitted for canceled meeting. doi: 10.1021/scimeetings.0c00021.

Journal: D. Araujo et al. Salivary uric acid is a predictive marker of body fat percentage in adolescents. Nutrition Research. Vol. 74, February 2020, p. 62. doi: 10.1016/j.nutres.2019.11.007.

Journal: S. Hicks et al. Oral microbiome activity in children with autism spectrum disorder. Autism Research. Vol. 11, September 2018, p. 1286. doi: 10.1002/aur.1972.

Journal: E. Pappa et al. Saliva proteomics analysis offers insights on Type 1 diabetes pathology in a pediatric population. Frontiers in Physiology. Vol. 9, April 26, 2018. doi: 10.3389/fphys.2018.00444.

About Kathiann Kowalski

Kathiann Kowalski reports on all sorts of cutting-edge science. Previously, she practiced law with a large firm. Kathi enjoys hiking, sewing and reading. She also enjoys travel, especially family adventures and beach trips.

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Lack of Saliva Production

A lack of saliva production has many causes, but it always leads to a condition commonly called dry mouth, although doctors sometimes refer to it as xerostomia. Possible causes of dry mouth include salivary gland injury or disease -- such as Sjögren's syndrome -- side effect from taking medication, complication from receiving cancer treatment, extreme dehydration, loss of blood and chronic mouth breathing. Dry mouth leads to many complications such as bad breath, painful swallowing, higher risk of dental infections and gum disease, difficulty talking and poor sense of taste.

What’s Going On When Something Goes Down the Wrong Pipe?

You’re at the ballgame with friends, snacking on peanuts. The bases are loaded, and then, just like that, your favorite player hits a grand slam!

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You rise to your feet to cheer — but some of those peanut crumbles in your mouth catch in your throat. After a coughing fit, you finally feel some relief. But what the heck just happened?

Something got sucked into your breathing tube instead of entering your food tube as it should.

What’s going on when something goes down “the wrong pipe” like that? It’s what doctors call aspiration.

How does aspiration happen?

When foreign material — food, drink, stomach acid, or fumes — enters your windpipe (trachea), it’s known as aspiration.

Normally, a well-coordinated muscle interaction in your lower throat propels food into your food tube (esophagus) and protects your airways. Your vocal cords and epiglottis help keep your airways closed off from food, drink or saliva.

It’s an automatic process, but sometimes something slips through the wrong way, especially when you’re distracted.

How does your body respond?

When you aspirate, your body’s fight-or-flight response triggers an outpouring of adrenaline and boosts your heart rate and blood pressure. A gag or cough reflex will start automatically and often fixes the problem, says Bohdan Pichurko, MD, Cleveland Clinic’s Pulmonary Function Lab Director.

“This is often brief if we promptly expel the aspirated material,” he says. “However, at the other extreme, it may follow eventually with fever and reduced oxygen levels, requiring medical attention for possible pneumonia.”

So how should you respond if your cough alone doesn’t do the trick?

  • Don’t panic.
  • Stop what you’re doing and lie on your belly with a cushion under your hips. This tilts your windpipe slightly downward, which can help expel the foreign material.

When to see a doctor

If you’re still coughing two to four hours after aspiration or if blood appears, call a doctor. Watch for fever, chills, and/or a cough that produces discolored mucus or sharp stabbing chest pain.

“Over 24 hours following aspiration, respiratory infection such as bronchitis or pneumonia may complicate the process,” Dr. Pichurko says. “When healthy, your bronchial tubes are sterile, delicate structures that don’t tolerate the intrusion of abnormal material.”

Repeated episodes of aspiration are sometimes a sign that you have another issue, he says.

Frequent aspiration accompanied by hoarseness may signal a vocal cord disorder. In this case, consult a physician who specializes in the ears, nose and throat for an examination.

Regular coughing that occurs during meals or repeatedly awakens you from sleep may point to a swallowing disorder or muscle coordination issues.

“Talk to your primary physician and he or she will likely arrange an X-ray swallowing study,” Dr. Pichurko says. “In the elderly, this may occur as an early sign of a neurological disorder such as Parkinson’s disease or previous stroke, or in the setting of severe muscle weakness due to an underlying chronic illness.”

Prevention tips

A few tips can help you avoid aspiration:

  1. Don’t talk with your mouth full. Talking keeps your airways open while you swallow, when they should be closed and protected.
  2. Take your time when you eat. Divide your food into small portions, and chew each bite thoroughly.
  3. Avoid heavy (fried and seasoned) foods at least three hours before bedtime. This helps keep your stomach from producing digestive juices that are more likely to prompt acid reflux and backwash into your esophagus, throat and lungs when you lie down.
  4. Take care of your teeth and gums. “With good oralhygiene , you can clear even the occasional aspiration quickly with no complicating infection from bacteria from your mouth or lasting damage to your bronchial tubes and lungs,” Dr. Pichurko says.

And if the batter smacks a home run at that baseball game? Make sure you swallow your peanuts before you start to cheer.

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Why Does Cancer Therapy Make Food Taste Terrible?

People who go through chemotherapy say one of the most frustrating side effects is that even their favorite foods taste awful. Pasta tastes like cardboard, meat tastes metallic. Patients have no desire to eat and end up getting fewer calories and less nutrition when they need it most&mdashto battle the cancer as well as the ravages of the therapy.

Why does chemotherapy ruin food&rsquos appeal? Does radiation therapy, often involved, make matters worse? Scientific American asked Beverly Cowart, director of clinical research at the Monell Chemical Senses Center in Philadelphia, to explain the mechanisms as well as strategies patients can use to make food more desirable.

[An edited transcript of the interview follows.]

Chemotherapy is supposed to work by killing cancer cells. How might that affect taste?
Cancer cells proliferate rapidly, and most chemotherapies target rapidly growing cells. Taste cells turn over rapidly, too stem cells in the base of a taste bud regularly replenish the taste cells. So the chemicals attack the taste cells as well. They either attach to a cell or enter it, then destroy it. As many cells die, taste disappears.

What about bad tastes, such as metallic or bitter sensations, instead of a lack of taste?
Like most medications the chemicals enter the bloodstream and they get into saliva that way. The saliva brings them to the taste cells and the cells send messages of &ldquometallic&rdquo or &ldquobitter&rdquo to neurons that lead to the brain. It&rsquos strange to think of it this way but we can &ldquotaste&rdquo things in the bloodstream. For example, researchers in Japan injected saccharin into people&rsquos bloodstreams and the people quickly tasted it.

Patients often complain of nausea. That also makes food less appetizing.
Right. Your body is programmed to tie nausea to something you ate. If you eat a specific food and get sick, you will find it hard to eat that food again. Cancer patients who feel nauseous become conditioned to avoid all kinds of foods they may be eating.

What about radiation?
If radiation is being used near the mouth area, such as for oral cancer, it can have an effect. Radiation elsewhere in the body does not. In these cases, even though the radiation is highly targeted, it&rsquos still impossible to avoid hitting salivary glands. The glands get knocked out, and the patient gets chronic dry mouth. For us to taste something, it has to go into solution so it can enter a taste bud&rsquos taste pore saliva is there to dissolve food into solution. Without saliva, it is hard to taste anything.

Does chemotherapy also affect smell, which is central to taste?
The smell system&rsquos receptors also interact with chemicals in the bloodstream, but the cells turn over more slowly than taste cells, so the chemicals might not attack them as much. They regenerate from stem cells, too, but that takes longer and it&rsquos more complicated, because smell cells are actually the ends of neurons, signaling the brain directly. When they regrow they have to mature and they also have to connect to the brain. Overall, smell cells get involved but they seem to be less affected than taste cells.

What are common, good tactics patients can use to help make food more appealing?
Because nausea makes you associate sickness with specific foods, don&rsquot eat the things you regularly eat before a chemotherapy treatment. Eat so-called scapegoat foods&mdashunusual or unusually flavored foods you wouldn&rsquot be likely to eat otherwise. You may end up hating them, but it won&rsquot matter for your other meals.

If the problem is diminished taste, rely on liquid nutrients to create solution that penetrates the taste pores&mdashespecially if you have dry mouth.

In general, eat slowly and chew a lot, to give food more of a chance to enter the few healthy taste buds that are there. Sour flavors tend to come through more readily, so things like lemon can be used to enhance flavor. To enhance smell, jack up the volatile compounds&mdashherbal ingredients and liquid spices.

Does taste return to patients after treatment is done?
With chemotherapy, once the drugs clear from the body the taste system usually returns over time. Recovery from radiation can take longer, even a few months, but there can also be some permanent damage to the salivary glands. Patients sometimes use artificial salivas to help themselves.

>>Also of interest: Tomorrow&rsquos Medicine, a Scientific American eBook>>

Your Saliva Says A Lot About Your Health: Here's What To Look For

Saliva is the key ingredient in food digestion, and helps protect teeth from decay, prevents infection, and makes chewing and swallowing possible. Without saliva we wouldn’t be able to break down food for proper digestion or wash away food and debris afterward.

Saliva is one of the best indicators of health, as it maintains balance in the body, so if something is off there’s a good chance your saliva has changed as a direct reflection. Spit screening can expose an array of biological secrets to doctors with just half of an eyedropper worth of spit. By just screening for a specific protein, doctors have the ability to assess heart disease risk.

When you’re stressed, salivary glands secrete an enzyme into the mouth known as salivary alpha-amylase and doctors can use it to gauge the amount of stress a mother places on her unborn babe. Conversely, if a female’s saliva contains abnormally low cortisol levels in the morning and high levels whenever she discusses stressful events or anxieties, there’s a good chance she doesn’t have a strong relationship with her father. Researchers found the imbalance of cortisol, the stress hormone, indicates emotional sensitivity to stressful situations.

Not only does it harbor 72 different types of bacteria, it’s also one of the most powerful painkillers thanks to the opiorphin it contains. Opiorphin is six times stronger than morphine and helps stop enkephalin pain signals from reaching the brain when the body undergoes an extreme amount of pain to maintain balance, according to the journal of Nature. Saliva is produced around the clock and is affected from every bite of food you take, to every stressful situation you find yourself in. There’s a lot saliva can tell about a person’s health, especially since the salivary glands produce two to four pints of it every day.

Dry mouth, also known as xerostomia, is when you don’t have enough saliva in your mouth, which everyone experiences from time to time. It’ll usually happen if you’re nervous, upset, or under a lot of stress. If you have dry mouth constantly, it can be very uncomfortable and cause difficulties in tasting, chewing, swallowing, and speaking.

A constant dry mouth can be an indication of some serious health problems or disease. If your saliva is thick or stringy, your body might be having a hard time producing saliva, which could be because of prescription and over-the-counter medications, including allergy, pain, and cold meds. They change the amount of water flow in and out of cells, and if left untreated, it can lead to tooth decay, gum disease, and oral yeast infections.

If you have pain or swelling in your neck and trouble swallowing in addition to dry mouth, you may have a salivary stone, also known as sialolithiasis. Saliva is full of calcium, and if it builds up in the salivary ducts, pale, crystallized rocks will form much like kidney stones.

Watch out for bright red and puffy gums, it’s one of the first signs of a bacterial infection or gum disease. Gum disease also indicates diabetes because of the high levels of glucose that accompany high blood sugar levels. Gum disease also increases levels of biological fluids that can induce labor if you’re pregnant. According to the American Academy of Periodontology, gum disease makes pregnant women seven times more likely to deliver their baby prematurely.

That’s not all your saliva can tell you about your health. Stick out your tongue and look in the mirror. If your tongue is a pale color, there’s a good chance you have iron-deficiency anemia, which affects one in five women. We get iron from leafy green vegetables, meat, seafood, and beans. Iron gives you energy and helps maintain your immune system. Without enough, your body can’t make hemoglobin, the pigment in red blood cells that give your tongue a pretty pink-red color.

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