Maybe you’re a coffee-shop junkie or
a cold-brew devotee. Or maybe you prefer to keep it old school with a trusty
drip coffeemaker. However you consume it, if you’re among the 59 percent of
Americans who drink coffee, that java buzz after downing a cup is probably
familiar to you.
But chances are, you aren’t aware of
the extent to which this beverage can affect nearly your entire body (from your
eyes to your blood) within minutes post-sip. We took a look at how a cup of
coffee affects the system right after you drink it — and some of what we found
is pretty astounding.
Your
Brain
If you need to buckle down and push through a tight deadline or stay
alert for a long drive, a mug of Joe can be your BFF. “Caffeine is a stimulant,
and some evidence shows that it can increase mental functioning and strengthen
your ability to concentrate,” says Marc Leavey, MD, a primary care specialist
at Mercy Medical Center in Baltimore.
In a nutshell, the brain works by sending out chemicals called
neurotransmitters through synapses — that’s how we are able to think. Caffeine
is a psychoactive compound that modulates these neurotransmitters, allowing
them to operate more efficiently. “As a result, the brain is able to better
process chemical messengers,” Leavey explains to Yahoo Health. “When used in
moderation, coffee gives you an edge.” You’ll begin to feel more mentally alert
after about 30 minutes, and the effects wear off a few hours later.
The key word, of course, is moderation. Too much caffeine can overwhelm
your system and sabotage your concentration, so that instead of feeling amped
up, you’re anxious and jittery.
Your Eyes
Caffeine also triggers your sympathetic nervous system (which regulates
your body’s unconscious activity), activating fight-or-flight mode. “It
stimulates the receptors in your brain that tell your body to rev up and
produce more adrenaline,” explains Nieca Goldberg, MD, cardiologist at NYU
Langone Medical Center. One possible outcome? Sharper vision.
“Research suggests that if you drink coffee, your pupils may dilate very
slightly,” Leavey says. “It’s so subtle that you wouldn’t be able to notice it
just by looking in the mirror, but you may feel that you can see better.”
Your Teeth
You know too much coffee can give your pearly whites a corn-kernel
effect, but there’s also an oral upside to your daily fix. “Coffee contains a
fair amount of polyphenols, micronutrients that have been shown to be effective
in killing oral plaque and bacteria,” says NYC-based dentist Keith Arbeitman.
The catch: As soon as you add milk, sugar, or
maple-gingerbread-Creamsicle-Nutella syrup, those very same benefits backfire.
“It’s a double-edged sword, because once the polyphenols dissolve the layer
of plaque, milk and sugar can easily access areas deep within the teeth,”
Arbeitman explains to Yahoo Health. “This leads to demineralization and
eventual decay.” Basically, as long as you stick to black, you’ll be doing your
teeth a favor. Otherwise, you’re making them even more vulnerable to cavities
than usual.
Those plaque-demolishing polyphenols are also responsible for exposing
your chiclets to discoloration, be it from the coffee itself or food you’re
eating at the same time. (Major offenders are berries, brightly colored candy,
and tomato or curry sauce. Arbeitman’s rule of thumb is that if it will stain
your shirt, it’ll stain your teeth.) “Try drinking from a straw to limit the
amount of time the sugars have to hang around in your mouth,” he suggests. “Or
brush your teeth afterward to correct your oral pH and neutralize residual
sugars.”
Your Heart
If you heart coffee, you should know that the most immediate physical
effects of a hit of java are indeed cardiovascular. “Caffeine increases the
sensitivity of your neural pathways so that the electrical impulses responsible
for triggering your cardiovascular system pass through the body more easily,”
Leavey says. “Consequently, about 15 minutes after drinking a cup, the caffeine
begins to elevate your pulse and blood pressure by an average of 10 to 15
percent.” (The exact amount varies depending on a bunch of factors — including
how much you’ve drunk, whether you’re a regular coffee-drinker, how much food
you’ve eaten, your weight, medications you’re taking, etc.)
According to Leavey, consuming two six-ounce cups a day isn’t hazardous
for most people, but a greater intake can be problematic if you have underlying
issues like heart disease, high blood pressure, or tachycardia
(faster-than-normal heart rate). “It may increase cardiovascular activity to
the extent that it can cause a heart attack,” he says.
Your Stomach
There’s some rationale behind downing an after-dinner espresso. “Caffeine
triggers the receptors in your stomach, boosting gastric secretions by about 10
to 15 percent — a small, but meaningful, increase,” says Leavey. These higher
levels of acid help you digest your meal faster.
The flip side of your G.I. tract’s elevated motility is potential
cramping, acid reflux, or heartburn. “Caffeine relaxes the sphincter, which is a
bundle of muscles located at the base of your esophagus that acts as a gate to
keep food from entering your trachea,” says Goldberg. “As a result, stomach
contents can travel backward into the esophagus.”
Your Bowels
Heads up: Skip this section if you’re eating — we’re gonna get a little
graphic. Hand-in-hand with a quick-acting stomach is lightning-fast bowel
activity … which means you may be struck by a tush-quake.
“Caffeine stimulates your bowels, telling them to work harder and
faster,” Leavey explains. “But fecal matter has to remain in the bowels for a
certain length of time in order to become a solid. If it moves too quickly, it
will emerge still in liquid form.” Irritable Bowel Syndrome (IBS) sufferers are
particularly at risk.
Your Bladder
As every devoted coffee drinker knows, it’s dangerous to gulp your way
through a Grande when you’re stuck in traffic or miles away from a bathroom.
“Coffee acts as a diuretic, influencing the tubules in your kidneys to send
more water through,” Leavey says. “That, in turn, leads to increased urinary
output.”
Interestingly, the diuretic effects exist whether you’re drinking regular
or decaf, so it’s not the caffeine at play. “Coffee contains other stimulating
compounds, including steroid-like molecules that physiologically provoke the
bowels and bladder,” Leavey adds.
Your Blood
Unless you’re indulging in a calorie-laden,
whipped-cream-and-chocolate-sauce-topped frozen coffee drink, you probably
don’t think of coffee as problematic in terms of cholesterol. But studies
suggest otherwise. “Coffee beans contain oils that are shown to increase
cholesterol,” Leavey says. “These oils are sifted out if you drink filtered
coffee, but not in a French press.” The next time you order an unfiltered brew,
check out the surface of your cup — you’ll see globules of fat floating on top.
Source Yahoo Health.
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