10 Scientific Benefits of Kissing

warrengoldswain, iStock /Getty Images Plus
warrengoldswain, iStock /Getty Images Plus

Kissing may be the most primal way we express affection with other humans. We kiss babies on their adorable chubby faces, friends on the cheeks, and lovers on the lips to demonstrate of our feelings and desire for closeness. Kissing may be one of the earliest evolutionary mechanisms for social bonding. While there are plenty of obvious pleasures of smooching, there are also some remarkable health benefits, backed by science. 

1. Kissing releases feel-good hormones.

Kissing activates the brain’s reward system, releasing neurotransmitters like oxytocin, "the love hormone," and vasopressin, which bonds mothers with babies and romantic partners to each other. It also releases endogenous opioids, dopamine, and other helpful neurohormones to keep our moods balanced.

2. Those feel-good hormones have healing abilities.

According to a 2005 study in Neuroendocrinology Letters, "[L]ove, pleasure, and lust have a stress-reducing and health-promoting potential, since they carry the ability to heal or facilitate beneficial motivation and behavior." In other words, by reducing your stress hormones, your body can better focus on healing any physiological processes that are exacerbated by stress, and help contribute to more positive mental health and behavior.

3. Kissing makes you more alert.

Kissing often stimulates the release of adrenaline and noradrenaline. Not only do these chemicals make you feel excited by increasing your heart rate, they make you more alert, as your body prepares for action … of any kind.

4. Kissing can reduce your stress levels.

According to affection exchange theory, as mentioned in a 2009 study in the Western Journal of Communication [PDF], physical exchanges of affection, including kissing, "buffer the individual against the physiological effects of stress." The researchers found that expressed affection, of which kissing is a prime example, was directly related to lowering the stress hormone cortisol throughout the day.

5. Reducing your stress could lower your cholesterol levels.

The same study authors theorize that if affectionate behavior reduces stress, "then it is logical to predict that it will also effect improvements on physiological parameters that are exacerbated by stress" such as cholesterol. Cholesterol has a number of essential physiological functions, they write, "including maintaining membrane fluidity, producing bile, and contributing to the metabolism of fat-soluble vitamins." It’s also "largely responsible" for the production of steroid hormones, such as cortisol, aldosterone, progesterone, the estrogens, and testosterone.

6. Kissing can reduce your allergy symptoms.

Allergic responses can be aggravated by stress. Since kissing reduces stress by sending those feel-good hormones mentioned earlier to the brain, as well as alleviating cortisol, a 2003 Japanese study in Physiology and Behavior explored the relationship between the stress-lowering activity of kissing on allergic reactions. Ninety participants were evenly divided into three groups: 30 with atopic dermatitis, 30 with allergic rhinitis, and 30 in a control group. In the study, the subjects, whom the authors noted "do not kiss habitually," kissed for 30 minutes with their partner in a private room while listening to soft music. They found that at the end of their smooch sessions, the participants experienced significant relief from skin wheals (hives) and plasma neurotrophin levels (a sign of allergic reaction) associated with Japanese cedar pollen and house dust mites. In 2015, this study won an Ig Nobel prize.

7. Kissing might boost your immunity.

When you kiss someone on the lips you exchange bacteria. This can either make you sick, or it can help boost your immunity by exposing you to new germs that strengthen your immune system's ability to fight these bacteria. A 2014 study in the journal Microbiome found that couples who kissed frequently were more likely to share the same microbiota in their saliva and on the surface of the tongue. How frequently? At least nine times per day.

8. A kiss a day might keep the dentist away.

The act of kissing stimulates your salivary glands to produce saliva, the fluid that moistens the mouth to make swallowing easier. Saliva also helps remove cavity-causing particles that stick in your teeth after eating. So while it might be a stretch to say kissing prevents cavities, it can’t hurt.

9. Kissing might help your determine the compatibility of your mate.

Perhaps the way you know you’ve found the one has nothing to do with their eyes, kind words, or the way they romance you, but very subtle cues you pick up through kissing. According to a 2013 study in the Archives of Sexual Behavior, kissing "might facilitate the subconscious appraisal of a potential mate by utilizing pheromonal cues to assess genetic … compatibility, general health, underlying genetic fitness or menstrual cycle phase and fertility." (Note the "might" here—we still haven't found evidence of human pheromones.) In fact, the authors write, in a handful of societies where mouth-to-mouth partner contact is unknown or frowned upon, such as the Mehinaku of Brazil (in fact, only 46 percent of cultures are known to kiss romantically), romantic partners still engage in "kissing traditions of close face-to-face contact involving sniffing, licking or rubbing."

10. Kissing might improve your relationship satisfaction.

The same study authors suggest that romantic kissing, as well as other forms of physical contact, can strengthen feelings of attachment to the person you're kissing, increasing the feeling of relationship satisfaction between romantic partners. And a 2013 study in the Archives of Sexual Behavior found that more frequent kissing was linked to couples’ perceived feelings about the quality of a relationship—namely, the more kissing, the happier they were—which was not the case for more sex.

This story originally ran in 2017.

10 Reusable Gifts for Your Eco-Friendliest Friend

Disposable tea bags can't compete with this pla-tea-pus and his friends.
Disposable tea bags can't compete with this pla-tea-pus and his friends.
DecorChic/Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

By this point, your eco-friendly pal probably has a reusable water bottle that accompanies them everywhere and some sturdy grocery totes that keep their plastic-bag count below par. Here are 10 other sustainable gift ideas that’ll help them in their conservation efforts.

1. Reusable Produce Bags; $13

No more staticky plastic bags.Naturally Sensible/Amazon

The complimentary plastic produce bags in grocery stores aren’t great, but neither is having all your spherical fruits and vegetables roll pell-mell down the checkout conveyor belt. Enter the perfect alternative: mesh bags that are nylon, lightweight, and even machine-washable.

Buy it: Amazon

2. Animal Tea Infusers; $16

Nothing like afternoon tea with your tiny animal friends.DecorChic/Amazon

Saying goodbye to disposable tea bags calls for a quality tea diffuser, and there’s really no reason why it shouldn’t be shaped like an adorable animal. This “ParTEA Pack” includes a hippo, platypus, otter, cat, and owl, which can all hang over the edge of a glass or mug. (In other words, you won’t have to fish them out with your fingers or dirty a spoon when your loose leaf is done steeping.)

Buy it: Amazon

3. Rocketbook Smart Notebook; $25

Typing your notes on a tablet or laptop might save trees, but it doesn’t quite capture the feeling of writing on paper with a regular pen. The Rocketbook, on the other hand, does. After you’re finished filling a page with sketches, musings, or whatever else, you scan it into the Rocketbook app with your smartphone, wipe it clean with the microfiber cloth, and start again. This one also comes with a compatible pen, but any PILOT FriXion pens will do.

Buy it: Amazon

4. Food Huggers; $13

"I'm a hugger!"Food Huggers/Amazon

It’s hard to compete with the convenience of plastic wrap or tin foil when it comes to covering the exposed end of a piece of produce or an open tin can—and keeping those leftovers in food storage containers can take up valuable space in the fridge. This set of five silicone Food Huggers stretch to fit over a wide range of circular goods, from a lidless jar to half a lemon.

Buy it: Amazon

5. Swiffer Mop Pads; $15

For floors that'll shine like the top of the Chrysler Building.Turbo Microfiber/Amazon

Swiffers may be much less unwieldy than regular mops, but the disposable pads present a problem to anyone who likes to keep their trash output to a minimum. These machine-washable pads fasten to the bottom of any Swiffer WetJet, and the thick microfiber will trap dirt and dust instead of pushing it into corners. Each pad lasts for at least 100 uses, so you’d be saving your eco-friendly friend quite a bit of money, too.

Buy it: Amazon

6. SodaStream for Sparkling Water; $69

A fondness for fizzy over flat water doesn’t have to mean buying it bottled. Not only does the SodaStream let you make seltzer at home, but it’s also small enough that it won’t take up too much precious counter space. SodaStream also sells flavor drops to give your home-brewed beverage even more flair—this pack from Amazon ($25) includes mango, orange, raspberry, lemon, and lime.

Buy it: Amazon

7. Washable Lint Roller; $13

Roller dirty.iLifeTech/Amazon

There’s a good chance that anyone with a pet (or just an intense dislike for lint) has lint-rolled their way through countless sticky sheets. iLifeTech’s reusable roller boasts “the power of glue,” which doesn’t wear off even after you’ve washed it. Each one also comes with a 3-inch travel-sized version, so you can stay fuzz-free on the go.

Buy it: Amazon

8. Countertop Compost Bin; $23

Like a tiny Tin Man for your table.Epica/Amazon

Even if you keep a compost pile in your own backyard, it doesn’t make sense to dash outside every time you need to dump a food scrap. A countertop compost bin can come in handy, especially if it kills odors and blends in with your decor. This 1.3-gallon pail does both. It’s made of stainless steel—which matches just about everything—and contains an activated-charcoal filter that prevents rancid peels and juices from stinking up your kitchen.

Buy it: Amazon

9. Fabric-Softening Dryer Balls; $17

Also great for learning how to juggle without breaking anything.Smart Sheep

Nobody likes starchy, scratchy clothes, but some people might like blowing through bottles of fabric softener and boxes of dryer sheets even less. Smart Sheep is here to offer a solution: wool dryer balls. Not only do they last for more than 1000 loads, they also dry your laundry faster. And since they don’t contain any chemicals, fragrances, or synthetic materials, they’re a doubly great option for people with allergies and/or sensitive skin.

Buy it: Amazon

10. Rechargeable Batteries; $40

Say goodbye to loose batteries in your junk drawer.eneloop/Amazon

While plenty of devices are rechargeable themselves, others still require batteries to buzz, whir, and change the TV channel—so it’s good to have some rechargeable batteries on hand. In addition to AA batteries, AAA batteries, and a charger, this case from Panasonic comes with tiny canisters that function as C and D batteries when you slip the smaller batteries into them.

Buy it: Amazon

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Scientists Come Closer to Understanding COVID-19 'Cytokine Storms'

Science is closer to understanding what prompts severe COVID-19 illness.
Science is closer to understanding what prompts severe COVID-19 illness.
Photo by Artem Podrez from Pexels

Researchers are one step closer to understanding the mechanisms behind "cytokine storms," an immune system reaction that can cause severe COVID-19 symptoms in patients infected with the coronavirus. In a new paper published in the journal Cell, scientists from St. Jude Children's Research Hospital describe their identification of the specific cytokines, or small proteins, that are produced by the body in an effort to fight the virus but sometimes overreact and wind up causing damage, including inflammation, lung injury, and organ failure.

After examining the many different kinds of cytokines in the body, researchers determined that no single cytokine caused this inflammatory response. Instead, it appears to be a combination of two specific cytokines, dubbed tumor necrosis factor (TNF)-alpha and interferon (INF)-gamma, that work in collusion to cause inflammatory cell death.

By identifying these proteins as the culprit, researchers suggested that administering neutralizing antibodies and disrupting the protein pathways that promote cell death might present a new treatment method for COVID-19.

COVID-19 can prompt a "cytokine storm" that can cause severe symptoms.St. Jude Children's Research Hospital

"Understanding the pathways and mechanism driving this inflammation is critical to develop effective treatment strategies," co-author Thirumala-Devi Kanneganti, vice chair of St. Jude's department of immunology, said in a press release. "This research provides that understanding. We also identified the specific cytokines that activate inflammatory cell death pathways and have considerable potential for treatment of COVID-19 and other highly fatal diseases, including sepsis."

Thus far, this theory has only been tested in mice, which received neutralizing antibodies and were protected from severe COVID-19 symptoms. But in isolating the exact cytokines involved, it will likely be easier to locate an effective treatment, either from an existing drug or one developed specifically for the task. In time, researchers hope clinical trials of select drugs can be another tool in the fight against the virus.

[h/t PennLive]