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Does cracking your knuckles give you arthritis? How much water should you REALLY drink a day? And what the HECK do crystals do for my health?
In this episode of Misconceptions, host Justin Dodd (@juddtoday) answers these burning questions about your health. Don't believe everything you read out there, your body will thank you.
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Misconceptions About Health & Wellness | Mental Floss
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0:00
Nothing like a glass of cold, clear water. Everybody knows that if you don't drink enough
0:06
water each day, you'll get dehydrated. Your lips, they'll turn dry. Your tongue
0:10
you'll feel fuzzy. You might pass out. There's an easy way to prevent this kind of dehydratory
0:16
discomfort, and that's drinking eight glasses of water a day. I mean, if there's one thing we know
0:21
for sure about adequate hydration is that a human being needs eight eight-ounce glasses of the stuff
0:27
daily, right? I mean, that's why we're all carrying around 16 or 24-ounce water bottles
0:32
so that we can easily calculate how many 8-ounce increments we consume each day, right? Well
0:37
we have a lot of misconceptions when it comes to health and wellness, from the cold-fighting
0:42
powers of vitamin C to whatever it is that crystals are supposed to do. Let's get started
0:47
Ugh, that's too much
1:02
You need to drink eight glasses of water a day. Your body loses water by breathing, sweating, and answering nature's call, and that water
1:09
needs to be replaced to maintain metabolism and other normal bodily functions
1:14
The Centers for Disease Control and Prevention does not specify the optimal amount of water
1:18
a person should drink each day. But in 2005, the Institutes of Medicine established adequate intakes of total water per day to
1:26
maintain health. Total water means the entire amount derived from drinking water, beverages, and food
1:33
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
1:42
2.7 liters for women. Men were drinking about 3 liters of actual liquids per day, and women were drinking 2.2
1:49
liters. That's actually more than 8 8-ounce glasses of water per day
1:53
So where does this 8-glasses idea come from? Back in 1945, the Food and Nutrition Board of the National Research Council released an
2:02
update to its bulletin, Recommended Dietary Allowances, which included guidelines for dietary standards. It's likely the earliest instance of a government recommendation for
2:11
daily water intake. Under a short section about water, the researchers wrote
2:16
A suitable allowance of water for adults is 2.5 liters daily in most instances. An ordinary
2:22
standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity
2:27
is contained in prepared foods. At work or in hot weather, requirements may reach 5 to 13 liters
2:34
daily. These guidelines might not be surprising considering they're not far from what the
2:38
Institutes of Medicine are recommending today. But according to a 2002 study, later researchers suggested that subsequent scientists and nutritionists
2:47
overlook that middle sentence, the one about most daily water needs being contained in food
2:53
Then, they misinterpreted the first sentences, recommending that people drink 2.5 liters
2:58
in addition to consuming other beverages and food. Since then, that misinterpretation has been repeated for decades
3:05
Some 2011 commentary in the medical journal BMJ even blamed multinational food conglomerates
3:11
for keeping this misconception going since it helped them sell more bottled water
3:16
Me personally, I'm a big La Croix boy, so when I'm drinking my unnecessary extra 2.5
3:22
liters of water a day, it's bubbly and tastes of Pomp-le-mousse. Caffeinated beverages dehydrate you
3:28
Okay, 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
3:37
you to think that all that peeing will lead to dehydration. But multiple studies dating
3:42
all the way back to 1928 have not found a strong link between caffeine and total water
3:47
deficit The Institutes of Medicine reports suggest that caffeinated beverages appear to contribute to the daily total water intake similar to that contributed by non beverages
3:59
Vitamin C prevents colds When you hear that a friend or family member has a cold, do you pop a vitamin C supplement
4:06
and hope you don't catch it? Maybe you take megadoses of vitamin C before you get on a plane so that the recycled air
4:12
doesn't make you sick. which—actually, the recycled air—is filtered to rid it of germs, but that's a misconception
4:18
for another video. The idea that vitamin C prevents the common cold has been around for a long time, so what's
4:25
the deal? Before vitamin C, also called ascorbic acid, was discovered in the early 20th century
4:31
people believed that eating certain fresh fruits and vegetables prevented illness. In the 1750s, Scottish physician James Lynn suggested citrus prevented scurvy, a lethal
4:40
disease that was endemic on long naval voyages. He didn't know that vitamin C was the active
4:46
ingredient preventing scurvy, but his years spent as a naval surgeon were enough to convince
4:50
him that fruits and veggies had a curative element. By 1795, the British Admiralty began
4:56
issuing rations of lemon juice. Later, that would get switched to lime juice, whence British sailors
5:02
got the nickname Limeys. In 1930, a Hungarian biochemist named Albert Saint-Gergy and a colleague
5:08
conducted an experiment on guinea pigs, which, like humans, cannot produce vitamin C within
5:13
their bodies as most animals can. St. Gurji fed one group of guinea pigs boiled foods
5:19
and another group ate food with the addition of what was then known as hexaronic acid
5:24
a molecule that he had discovered during his earlier study of biological combustion
5:28
The animals that ate boiled foods without the hexaronic acid developed scurvy-like symptoms
5:33
and died, because boiling food gets rid of the food's vitamin C
5:37
The group that ate hexaronic acid-laced foods remained healthy. St. Gurgy renamed the molecule ascorbic acid to note its anti-scurvy or anti-scorbutic
5:47
property. After more experiments to confirm his findings, St. Gurgy was awarded the Nobel Prize
5:52
in Physiology or Medicine in 1937 for his discovery of vitamin C. Good work, my guy
5:58
We now know that vitamin C enables the body to use carbs, proteins, and fats for healthy bones
6:04
teeth, gums, blood vessels, and ligaments. It also lowers your risk of cardiovascular disease and
6:10
cancer. But beyond those health benefits, vitamin C has not been shown in studies to prevent colds
6:16
for most people. Some studies have suggested that taking large doses of vitamin C may lessen the
6:21
severity or duration of cold symptoms, but generally it does not have these effects if
6:26
you start taking it after the cold hits you. One paper also determined that for marathon runners or
6:31
soldiers doing exercises in sub-Arctic conditions, there might be a benefit, but that doesn't
6:37
apply to the vast majority of us. The widely held opinion that vitamin C prevents colds probably stems from the work of another
6:43
Nobel laureate, Linus Pauling, one of the giants of 20th century science
6:49
This chemist and peace activist won the Nobel Prize in Chemistry in 1954 for his work understanding
6:54
chemical bonds, and a few years later won the Nobel Peace Prize for his actions opposing
6:59
the nuclear arms race during the Cold War. In the 1970s, Pauling became interested in
7:04
a string of inconclusive studies of vitamin C and colds. After yzing the literature
7:10
Pauling published a bestseller called Vitamin C and the Common Cold, which made specific
7:14
recommendations for readers. He wrote that 1 to 2 grams of ascorbic acid per day is approximately
7:20
the optimum rate of ingestion. There's evidence that some people remain in very good health
7:26
including freedom from the common cold year after year through the ingestion of only 250mg of ascorbic acid per day
7:34
He also said you should carry 500mg vitamin C tablets with you at all times
7:39
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
7:53
While we're on the topic, what is the deal with chicken noodle soup for treating colds
7:57
Well, some studies have found that like vitamin C, chicken soup may lessen the symptoms and
8:03
length of colds. The 2000 study in the journal Chest found a mild anti-inflammatory effect from chicken
8:09
soup which seemed to clear cold-suffer stuffy airways. But they were unable to tell which
8:14
ingredient—chicken, onion, carrots, sweet potatoes—was responsible. Cracking your knuckles is bad for your joints
8:23
Ooh, feels really good to crack your knuckles, or your neck or other body parts. But are you
8:29
sacrificing the long-term health of your joints for a fleeting burst of pleasure
8:33
First, let's talk about why your joints crack. Your knuckles are where your metacarpals, or
8:38
hand bones connect with the proximal phalanges, or finger bones. The area where the bones meet
8:44
is cushioned by a structure called the synovial capsule, which is filled with a lubricating fluid
8:49
containing dissolved gases and nutrients. When you pull or bend your fingers backwards to crack
8:54
your knuckles, you stretch the synovial capsule and create more space inside. Gases rush into
9:00
the resulting vacuum, creating a bubble. That sound of the knuckles cracking corresponds to
9:05
the formation of those bubbles. After the bubbles form, the gases take a while to redissolve
9:10
in the fluid, which is why you can't crack your knuckles again right after doing it
9:14
And even though I just said those words and researched the matter thoroughly, I'm still
9:18
going to try every five minutes. So anyway, repeatedly popping your synovial capsules sounds bad, but does it cause joint
9:26
damage like arthritis? One physician in Thousand Oaks, California was determined to find out
9:31
using himself as a test subject. When he was a child, Donald Unger's mother and aunts repeatedly told him that cracking
9:37
his knuckles would cause arthritis. Out of curiosity, or perhaps spite, he began cracking his left hand's knuckles twice a
9:45
day for 50 years. He avoided cracking his right hand to use it as a control
9:50
After approximately 36,500 left-knuckle cracks, Unger compared his hands and found no presence
9:57
of arthritis in either one. Though the study's sample size himself was too small to confirm population-scale results
10:05
Unger wrote in the journal Arthritis and Rheumatism in 1998, and the findings supported a 1970s
10:11
study of 28 nursing home residents that found no link between knuckle-cracking and arthritis
10:16
For his valuable contributions to science, Unger received the 2009 Ig Nobel Prize for Medicine
10:23
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
10:30
A 1990 study found that people who cracked their knuckles had less grip strength and
10:35
more hand swelling than those who did not. Another report described minor injuries to ligaments and tendons in the joints, which
10:43
healed within a month. But these were minor effects and did not lead to arthritis
10:48
So crack away knowing that the worst consequence of your knuckle popping will likely just be
10:54
annoying your friends and co-workers. Oh, that was a bad one. Oh, did you hear that
11:01
There we go. Crystals have inherent healing properties. Oops, sorry, I was just adjusting my giant Gwyneth Paltrow-approved amethyst to rid this
11:11
room of any bad vibes. You know, a lot of people put their faith in healing crystals
11:15
They might hold a rose quartz if they're seeking love, or sleep with obsidian on their
11:20
pillow to feel calm and grounded. Let's look at where these notions originated. In the first century CE, the Roman scholar
11:27
Pliny the Elder described various precious stones and the healing remedies associated
11:31
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
11:46
ailments. Pliny also sought to describe crystals in relatively scientific terms. He wrote that
11:51
crystal, what we would call rock crystal or quartz today, was formed from rainwater and
11:55
pure snow, congealing over time into a solid, clear, often spiky material. While Pliny didn't
12:02
eating or drinking it, he said that medical men had told him that it made a great lens
12:07
for use in surgery. The very best cautery for the human body is a ball of crystal acted upon by the
12:12
rays of the sun, he wrote. The supposed link between crystals and health or medicine was
12:18
well established by the Middle Ages. At that time, Christian writers in Europe mentioned crystals in
12:23
their works and important religious books were bound in covers encrusted with crystals and
12:28
precious stones. According to Stanford University medievalist Marissa Galvez, crystals symbolized transcendence and intellectual illumination. Among Christians, they also became associated
12:39
with purity, faith, and perfection, all characteristics of the Virgin Mary, who
12:43
not coincidentally, was believed to have a healing touch. Skipping past the Enlightenment, by the late 19th century, crystals gained value among
12:52
spiritualists in the UK and the US. Gazing into crystal balls for visions of the future or
12:57
answers to existential questions became a major fad. Some spiritualists identified crystals
13:03
as a kind of holistic medicine, perhaps in the same category as then-popular patent drugs
13:09
and potions. Others associated this self-curated healthcare with values like self-reliance, self-awareness, creativity, and psychological growth
13:17
In the 1970s and 80s, healing crystals got another boost in the New Age movement
13:22
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
13:32
illness can be traced to an imbalance among the three. Crystals are thought to help maintain the
13:37
balance in one way or another. That theory underlies the concept of complementary medicine
13:42
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
13:55
These remedies are gaining legitimacy today. There's even a center at NIH focused on studying
14:00
its efficacy. And at least one researcher in the UK has looked at crystal healing as a form
14:05
of complementary medicine. But behind all this, researchers have found that crystals' supposed
14:10
healing powers are most likely a result of the placebo effect. For example, a crystal user might
14:16
convince herself that the stones can improve her mood and actually feel better while holding them
14:22
or meditating with them, even if the stones have no intrinsic mood-boosting properties
14:27
But the placebo effect is real, scientists have found, and can help patients improve their outlook
14:32
while undergoing treatments. For some patients, the belief in the power of a non-medical
14:36
intervention like prayer or crystals can actually improve the effectiveness of Western medical
14:42
practices. So if you find crystals helpful, have at it. Just know that your mind is more powerful
14:48
than a mineral. Whoa. Mind is more powerful than a—someone put that on a t-shirt
14:53
Thank you all for watching Mental Floss on YouTube. I hope you learned a little bit about health
14:58
and wellness. By the way, did you know that we have like a million of these episodes on our
15:03
channel? Okay, I mean that's a bit of a hyperbole, but we have a lot, like 900,000 or something. I
15:08
haven't checked lately. Click the little box on your screen to go check out the rest of Misconceptions
15:13
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
15:21
Don't forget to subscribe, and I will see you next time. That was too much at once
15:33
Oh, God
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