Because coffee has a naturally high concentration of caffeine, its health effects have been studied in depth. One 8 ounce cup of coffee has between 100 and 200 milligrams of caffeine, with the average being around 135. Per ounce, coffee has the single highest caffeine concentration of any naturally made beverage (excluding certain energy drinks). What’s more, since disclosure about caffeine content isn’t required by the United States government, it’s often a challenge to figure out just how much caffeine you’re consuming. According to most studies, the average American consumes between 200 and 400 milligrams of caffeine per day – about 2 to 3 cups of coffee. In this article, we’ll go in depth to figure out just what that caffeine consumption’s effects on health are.
Caffeine’s Immediate Effects
Every time you take a sip of coffee, caffeine molecules enter the bloodstream, and eventually the brain. Because of its chemical structure, it fits in the brain’s adenosine receptors, effectively dampening their function. While you might think that brain sensor dampening would have a sedative effect, the blocking of these receptors actually does just the opposite. As the caffeine molecules go two work, several effects are immediately noticeable.
Just a few moments after caffeine consumption, its effects begin. The first thing the caffeine consumer will notice is an almost immediate “wake up” feeling. This is the caffeine reacting with those adenosine receptors in the brain, mimicking natural sources of energy. As this happens, heart rate increases, attentiveness increases, brain activity increases, and blood flow typically rises moderately. These immediate effects are a big reason why caffeine and coffee are so popularly consumed, especially in the morning. They serve to increase the average person’s alertness significantly, helping them feel “fresh” and ready for the day. But along with these intended effects come some unintended side effects. Most notable is caffeine’s action as a diuretic, which is basically just an increase in urine flow and decrease in retained water in the body. As many coffee drinkers know, the urge to use the bathroom typically comes pretty quickly once caffeine is consumed.
Caffeine Over-cunsumption
At one point or another, almost every coffee drinker has experienced the results of having one cup too many. Also known as caffeine intoxication or overdose, over-consumption of caffeine essentially ramps up its intended effects to uncomfortable levels..Generally, it happens to people with either a low tolerance for caffeine or those who consume more than 600 milligrams in a day.
To know whether you’ve overdone it with the coffee, there are several symptoms to look for. First and foremost are the psychological effects. Going overboard on caffeine will, for a time, make you more anxious, irritable, and restless. The heart, meanwhile, will race almost as if the caffeine drinker is engaging in intense aerobic exercise. In some relatively rare cases, the heart will even beat with an abnormal rhythm. In the muscles, an overdose of caffeine typically results in over-activity. Twitching and trembling of the extremities – especially the hands and fingers – is very common. Other symptoms to keep an eye out for include dizziness, headache, ringing ears, and blurry vision. As uncomfortable as a caffeine overdose might be, there’s no need for the average coffee drinker to worry. It would take 80 to 100 cups of coffee consumed pretty much as fast as possible for caffeine to be potentially lethal in humans.
Chronic Caffeine Effects
In addition to the first tier of side effects, there is a second subset of health consequences that coffee consumption can have. Specifically, they usually become apparent in people who drink lots of coffee every day. These effects most often are limited to dehydration, insomnia, and headaches. All three result from the significant stimulant and diuretic qualities of caffeine. As the body becomes used to caffeine exposure, though, these effects often diminish over time.
With enough consistent caffeine consumption, a dependence may develop. Like many other drugs, caffeine is considered to be an addictive substance by the medical community. If you’ve ever had a headache or felt generally uncomfortable because you haven’t had your coffee, then you know what caffeine dependence feels like. Caffeine addiction is much milder physically than many other drugs – but it is enough to keep people drinking coffee almost automatically day in and day out. Of course, along with dependence comes withdrawal in the absence of the substance. As mentioned before, those who are dependent on caffeine may experience mild symptoms like headache and anxiety. They result from the fact that caffeine tends to constrict blood vessels. When those vessels are no longer constricted as caffeine leaves the body, more blood goes to the head – resulting in increased pressure and discomfort. The “crash”, often dreaded by caffeine users, is in reference to these withdrawal effects.
Caffeine and the Brain
With all the direct brain receptor processes that caffeine involves itself in, it is worth noting the substance’s overall neurological effects. A scientific study recently concluded that about a cup of coffee’s worth of caffeine, because of its nature as a stimulant, actually increases brain function. Specifically, it puts the part of the brain that works to store and retrieve memories in overdrive. Another related study showed that subjects who took in moderate amounts of caffeine performed better on standard memory tests than their non-caffeinated counterparts. But, like the physiological and bodily effects of caffeine, this increased brain function is short lived. In fact, the “crash” that comes later would likely neutralize any enhanced productivity and focus from that morning cup of coffee.
Coffee and Weight Loss
Because of the way coffee and its main active ingredient operate in the body, many people consider weight loss to be an added benefit of the drug. But why would this substance affect your weight? The answer lies in the fact that caffeine is a stimulant. By simple, natural bodily processes, caffeine can actually affect your metabolism. Basic bodily maintenance functions – things like breathing and blood circulation – require energy to perform. Caffeine increases the volume and intensity of these functions, requiring more energy. Additionally, evidence has shown that at the cellular level, caffeine increases the prevalence of a process called thermogenesis. In essence, this means that cells produce heat from energy sources as opposed to energy that the body can store as fat.
Despite these proven instances that support coffee as a catalyst for weight loss, there is also evidence that argues coffee can actually cause weight gain. Specifically, some scientific studies argue that caffeine consumption raises certain stress hormone levels. This, in turn, triggers excess fat storage and weight gain. When it comes down to brass tax, there is simply no conclusive evidence for either side of the coffee and weight loss argument.
Coffee Consumption During Pregnancy
In recent years, health organizations have stressed that excess consumption of caffeine can be dangerous for pregnant women. As opposed to eliminating intake altogether, though, they recommend limiting its consumption. In one study, 431 pregnant women were given up to 300 milligrams of caffeine per day. The outcome was that no correlation between caffeine and birth defects or miscarriages was found. Another study was completely contradictory, finding that consumption of more than 200 milligrams of caffeine per day effectively doubled the risk of miscarriage. The only definitive key, it seems, is the amount of caffeine consumed. Because the substance has been proven to have an ability to reach ovarian fluids, it is strongly recommended by doctors that coffee consumption be limited in general. Most agree that under 200 milligrams of coffee per day– the equivalent of one to two cups – is safe for pregnant women to consume.
Kids and Caffeine
One of the most popular old wives’ tales mothers tell their children is that caffeine will stunt their growth. And though this has proven to be false, there is a genuine cause for concern about kids and caffeine consumption. Though kids typically aren’t coffee drinkers by tradition, “trendy” coffee purveyors are changing that notion. Their marketing has targeted increasingly younger consumers – making the idea of hanging out at the coffee shop especially popular among tweens and teens nationwide. This raises the legitimate question of how coffee and caffeine affect children specifically.
The chief concern for caffeine’s effects on children in particular fall within the psychological areas of study. In one experiment done by the National Institute of Mental Health, tweens and young teenagers who took in elevated amounts of caffeine had a high prevalence of symptoms consistent with hyperactivity. With the incidences of ADHD on a significant upturn, this is a real concern. Altered moods created by caffeine and caffeine withdrawal are also shown to have adverse effects in the classroom. By most accounts, it's recommended to keep kids under 13 on a caffeine-restricted regimen. So, if you’ve got a child who’s quickly becoming a coffee fiend, it might be worth considering making the switch to decaf.
Coffee’s Long Term Health Effects
Of all the health effects of caffeine and coffee, the long term ones are perhaps the least well known. Because these types of longitudinal (long-term) studies are much harder to perform, empirical evidence is severely limited in the matter. There is, however, some information about what coffee consumption’s health effects are in the long term.
With the added stress that caffeine puts on the heart by raising heart rate, it is natural to assume that there may be some cardiovascular consequences of coffee consumption in the long term. But because there are so many lifestyle and genetic variables affecting the heart’s performance, studies often come up inconclusive. Heart disease is without a doubt on the rise in the United States. Most of that rise is accredited to an increase in the prevalence of obesity among Americans, but caffeine may be a contributing factor. The stress hormones that caffeine consumption releases, for example, are thought to take a minor toll on heart health. But, on the other hand, certain medical studies have shown that elderly people who drink coffee regularly might in fact be more resistant to heart disease than those who don’t. What is known is that, unlike soft drinks, coffee does not have any long term effect on heart rhythm or blood pressure – certainly good news for coffee lovers. The overarching theme concerning coffee and heart health, much like coffee and weight loss, is that the jury is still out. While there are possible negative effects on the heart from caffeine consumption, offsetting positive ones are just as likely.
The other oft-studied effect of caffeine consumption on long term health is bone density. Women, especially, have a high risk of bone loss and Osteoporosis as they age. Scientific experiments suggest that women who take in amounts above the high dosage caffeine level of 300 milligrams per day have a higher incidence of bone loss in essential areas – including the spine – than those who don’t. Luckily, many coffee drinkers can offset this disheartening effect relatively easily. Instead of using powdered creamer in their coffee, it is recommended that women start using milk as a coffee creamer around the age of menopause. Because milk is rich in calcium and Vitamin D, it helps maintain bone density despite the presence of caffeine in the body.
The Bottom Line
When taking coffee’s relationship to health into consideration, it is important to remember one simple principle: moderation. Like most everything else, applying a healthy dose of common sense in tandem with that dose of caffeine goes a long way to preserving your long term health. In general, there are just a few things to remember about coffee consumption and health.
The first, dealing with caffeine’s immediate effects, is to pay attention to your body. If your extremities start to shake and your heart gets fluttering, it’s probably a good idea to lay off the coffee for a few hours.
Second, don’t expect caffeine to act as a mental enhancement substance for too long, and definitely don’t use it as such.
Similarly, caffeine should not be treated as a silver bullet for weight loss.
When it comes to the kids, keeping caffeine dosage as low as is reasonably possible is recommended – including yourself if you have one on the way.
Finally, women over 45 should skip the powdered creamer and use real milk to flavor their coffee.
With these relatively simple rules in mind, there’s no reason that coffee shouldn’t have positive – if minor – effects in an already healthy lifestyle.
