Ahh, nothing like a glass of cold, clear water. Everybody knows that if you don’t drink
enough water each day, you’ll get dehydrated. Your lips will turn dry, your tongue will
feel fuzzy, and you might pass out.
There’s an easy way to prevent this kind of dehydratory discomfort—and that’s drinking
8 glasses of water a day. I mean, if there’s one thing we know for sure about adequate
hydration, it’s that a human being needs eight 8-ounce glasses of the stuff daily.
Right? I mean, that’s why we’re carrying around 16- to 24-ounce water bottles? So we
can easily calculate how many 8-ounce increments we consume each day, right?
Well, we have a lot of misconceptions when it comes to health and wellness, from the
cold-fighting powers of Vitamin C to whatever it is that crystals are supposed to do. Let’s
get started.
It's too much.
Your body loses water by breathing, sweating, and answering nature’s call, and that water
needs to be replaced to maintain metabolism and other normal bodily functions.
The Centers for Disease Control and Prevention does not specify the optimal amount of water
a person should drink each day. But in 2005, the Institutes of Medicine established “adequate
intakes” of total water per day to maintain health. “Total water” means the entire
amount derived from drinking water, beverages, and food—and yes, that includes caffeinated
drinks like coffee, tea, and soda.
Based on survey data, the adequate intake for young adults is 3.7 liters for men and
2.7 liters for women. Men were drinking about 3 liters of actual liquids per day, and women
were drinking 2.2 liters. That’s actually more than eight 8-ounce glasses of water per
day.
So where does this “8 glasses” idea come from?
Back in 1945, the Food and Nutrition Board of the National Research Council released
an update to its bulletin Recommended Dietary Allowances, which included guidelines for
dietary standards. It’s likely the earliest instance of a government recommendation for
daily water intake. Under a short section about water, the researchers wrote:
These guidelines might not be surprising, considering they’re not far from what the
Institutes of Medicine are recommending today.
But according to a 2002 study, later researchers suggested that subsequent scientists
and nutritionists overlooked the middle sentence—the one about most daily water needs being contained
in food. Then, they misinterpreted the first sentence as recommending that people drink
2.5 liters in addition to consuming other beverages and food. Since then, that misinterpretation
has been repeated for decades. One 2011 commentary in the medical journal BMJ even blamed multinational
food conglomerates for keeping this misconception going, since it helped them to sell more bottled water.
Me personally, I’m a big La Croix Boy so when I’m drinking my unnecessary extra 2.5 liters of water,
it’s bubbly, and tastes of pamplemousse.
OK, but going back to caffeine—don’t caffeinated beverages dehydrate you? Caffeine does have
a diuretic effect—meaning it makes you pee more—and that might lead you to think that
all that peeing will lead to dehydration. But multiple studies, dating all the way back
to 1928, have not found a strong link between caffeine and total water deficit. The Institutes
of Medicine report suggests that “caffeinated beverages appear to contribute to the daily
total water intake, similar to that contributed by noncaffeinated beverages.”
When you hear that a friend or family member has a cold, do you pop a Vitamin C supplement
and hope you don’t catch it? Maybe you take megadoses of Vitamin C before you get on a
plane so the recycled air doesn’t make you sick (actually, the recycled air is filtered
to rid it of germs, but that’s a misconception for another video). The idea that Vitamin
C prevents the common cold has been around for a long time, so what’s the deal?
Before Vitamin C—also called ascorbic acid—was discovered in the early 20th century, people
believed that eating certain fresh fruits and vegetables prevented illness.
In the 1750s, Scottish physician James Lind suggested citrus prevented scurvy, a lethal
disease that was endemic on long naval voyages. He didn’t know that Vitamin C was the active
ingredient preventing scurvy, but his years spent as a naval surgeon were enough to convince
him that fruits and veggies had a curative element. By 1795, the British Admiralty began
issuing rations of lemon juice. Later that’d get switched to lime juice, whence British
sailors got the nickname ‘limeys.”
So there was a strong case for consuming lime, lemon, and other fruits for good health by
the early 20th century, but the mechanism behind it was still unknown. Researchers struggled
to pinpoint the molecules or chemicals responsible. In 1930, a Hungarian biochemist named Albert
Szent-Györgyi and a colleague conducted an experiment on guinea pigs, which—like humans—cannot
produce Vitamin C within their bodies as most animals can. Szent-Györgyi fed one group
of guinea pigs boiled foods, and another group ate food with the addition of what was then
known as hexuronic acid, a molecule that he had discovered during his earlier study of
biological combustion.
The animals that ate boiled foods without the hexauronic acid developed scurvy-like
symptoms and died, because boiling gets rid of the foods’ Vitamin C. The group that
ate hexuronic acid-laced foods remained healthy. Szent-Györgyi renamed the molecule “ascorbic
acid” to note its anti-scurvy (or anti-scorbutic) property.
After more experiments to confirm his findings, Szent-Györgyi was awarded the Nobel Prize
in Physiology or Medicine in 1937 for his discovery of Vitamin C. Good work, my guy.
We know now that Vitamin C enables the body to use carbs, proteins, and fats for healthy
bones, teeth, gums, blood vessels, and ligaments. It lowers your risk of cardiovascular disease
and cancer.
But beyond those health benefits, Vitamin C has not been shown in studies to prevent
colds for most people. Some studies have suggested that taking large doses of Vitamin C may lessen
the severity or duration of cold symptoms, but generally, it doesn’t have these effects
if you start taking it after the cold hits you. One paper also determined that for marathon
runners or soldiers doing exercises in sub-arctic conditions there might be a benefit, but that
doesn’t apply to the vast majority of us.
The widely held opinion that Vitamin C prevents colds probably stems from the work of another
Nobel Laureate—Linus Pauling, one of the giants of 20th-century science. This chemist
and peace activist won the Nobel Prize in Chemistry in 1954 for his work understanding
chemical bonds, and a few years later won the Nobel Peace Prize for his actions opposing
the nuclear arms race during the Cold War. Jeez, I guess if you want a Nobel prize, just
study vitamin C, it’s a fast track to scientific glory apparently.
In the 1970s, Pauling became interested in a string of inconclusive studies of Vitamin
C and colds. After analyzing the literature, Pauling published a bestseller called Vitamin
C and the Common Cold, which made specific recommendations for readers. He wrote that
1 to 2 grams of ascorbic acid per day
He also said you should carry 500-milligram Vitamin C tablets “with you
at all times.”
While the American public rushed out to buy Vitamin C supplements, skeptical researchers
launched more than two dozen studies about these claims, and even today, no study has
shown conclusively that ascorbic acid prevents colds among the general population.
While we’re on the topic, what’s the deal with chicken soup for treating colds? Some
studies have found that, like Vitamin C, chicken soup may lessen the symptoms and length of
colds. A 2000 study in the journal CHEST found a mild anti-inflammatory effect from chicken
soup, which seemed to clear cold sufferer’s stuffy airways. But, they were unable to tell
which ingredient—chicken, onion, sweet potatoes, carrots, et cetera—was responsible.
It feels really good to crack your knuckles, or your neck, or other body parts. But are
you sacrificing the long-term health of your joints for a fleeting burst of pleasure?
First, let’s talk about why your joints crack. Your knuckles are where your metacarpals,
or hand bones, connect with the proximal phalanges, or finger bones. The area where the bones
meet is cushioned by a structure called the synovial capsule, which is filled with a lubricating
fluid containing dissolved gases and nutrients.
When you pull or bend your fingers backward to crack your knuckles, you stretch the synovial
capsule and create more space inside it. Gases rush in to the resulting vacuum, creating
a bubble. That sound of the knuckles cracking corresponds to the formation of those bubbles.
After the bubbles form, the gases take a while to re-dissolve in the fluid, which is why
you can’t crack your knuckles again right after doing it. And even though I just said
those words, and researched thee matter thoroughly… I’m still gonna try every five minutes.
So anyway, repeatedly popping your synovial capsules sounds bad—but does it cause joint
damage like arthritis? One physician in Thousand Oaks, California, was determined to find out,
using himself as a test subject.
When he was a child, Donald Unger’s mother and aunts repeatedly told him that cracking
his knuckles would cause arthritis. Out of curiosity—or perhaps spite—he began cracking
his left hand’s knuckles twice a day for 50 years. He avoided cracking his right hand
to use it as a control. After approximately 36,500 left knuckle cracks, Unger compared
his hands and found no presence of arthritis in either one. Though the study’s sample
size—himself—was too small to confirm population-scale results, Unger wrote in the
journal Arthritis and Rheumatism in 1998, the findings supported a 1970s study of 28
nursing home residents that found no link between knuckle cracking and arthritis.
For his valuable contributions to science, Unger received the 2009 Ig Nobel Prize for
Medicine.
In the years following the start of Unger’s experiment, there have been a handful of studies
examining the possibility of a link between knuckle-cracking and joint damage. A 1990
study found that people who cracked their knuckles had less grip strength and more hand
swelling than those who didn’t. Another report described minor injuries to ligaments
and tendons in the joints, which healed within a month. But these were minor effects,
and didn’t lead to arthritis. So, crack away, knowing that the worst consequence of
your knuckle-popping will likely be annoying your friends and co-workers.
Oh that was a bad one. Oh did you hear that??
There we go.
Oop sorry, was adjusting my giant Gwyneth Paltrow-approved amethyst to rid the room
of any bad vibes. You know, a lot of people put their faith in healing crystals—they
might hold a rose quartz if they’re seeking love, or sleep with obsidian on their pillow
to feel calm and grounded. Let’s look at where these notions originated.
In the 1st century CE, the Roman scholar Pliny the Elder described various precious stones,
and the healing remedies associated with them, in his massive book Natural History. Most
of the remedies involved ingesting the stones in some form along with food or drink. For
example, hematite was “taken with wine for the cure of wounds inflicted by serpents,”
among other ailments.
Pliny also sought to describe crystals in relatively scientific terms. He wrote that
crystal—what we would call rock crystal or quartz today—was formed from rain water
and pure snow, congealing over time into a solid, clear, often spiky mineral. While Pliny
didn’t suggest eating or drinking it (ouch), he said that “medical men'' had told him
that it made a great lens for use in surgery.
The supposed link between crystals and health or medicine was well established by the Middle
Ages. At that time, Christian writers in Europe mentioned crystals in their works, and important
religious books were bound in covers encrusted with crystals and precious stones. According
to Stanford University medievalist Marisa Galvez, crystals symbolized transcendence
and intellectual illumination. Among Christians, they also became associated with purity, faith,
and perfection, all characteristics of the Virgin Mary—who, not coincidentally, was
believed to have a healing touch.
Skipping past the Enlightenment, by the late 19th century, crystals gained value among
spiritualists in the UK and the U.S. Gazing into crystal balls for visions of the future
or answers to existential questions became a major fad. Some spiritualists identified
crystals as a kind of holistic medicine—perhaps in the same category as then-popular patent
drugs and potions. Others associated this self-curated healthcare with values like self-reliance,
self-awareness, creativity, and psychological growth.
In the 1970s and ‘80s, healing crystals got another boost in the New Age movement,
which explored gray areas between science, magic, nature, and the occult. One overarching
New Age belief is that health is a balance of body, mind, and spirit, and that illness
can be traced to an imbalance among the three. Crystals are thought to help maintain the
balance in one way or another.
That theory underlies the concept of complementary medicine, sometimes called alternative medicine—which
also includes acupuncture, music therapy, herbal remedies, prayer, yoga, and other practices
used with or in place of modern Western medicine. These remedies are gaining legitimacy today—there’s
even a center at NIH focused on studying its efficacy. And at least one researcher in the
U.K. has looked at crystal healing as a form of complementary medicine.
But behind all this, researchers have found that crystals’ supposed healing powers are
most likely a result of the placebo effect. For example, a crystal user might convince
herself that the stones can improve her mood, and actually feel better while holding them
or meditating with them, even if the stones have no intrinsic mood-boosting properties.
The placebo effect is real, scientists have found, and can help patients improve their
outlook while undergoing treatments. For some patients, the belief in the power of a non-medical
intervention, like prayer or crystals, can actually improve the effectiveness of Western
medical practices. So if you find crystals helpful, have at it—just know that your
mind is more powerful than a mineral. Your mind is more... Someone put that on a t-shirt.
Thank you all for watching Mental Floss on Youtube, I hope you learned a little bit about
health and wellness. By the way, did you know we have like
a million of these on our channel? Okay that’s a hyperbole but we have a lot. Like, 900,000 or something
I haven't checked lately. Click the little box on your screen to go check out the rest of Misconceptions, or
some of our other shows, like The List Show or Food History. You're
gonna learn so many things and definitely be the smartest person at your next Zoom party.
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It was too much at once. *burp* Oh god...