Caffeine is one of the most popular and commonly used drugs in the world and is consumed by up to 90% of the global population in some form or another. Despite caffeine’s frequent use, however, many people don’t really know how caffeine affects their health or even how much they are taking in on a daily basis.
The average person person consumes about 200 mg (about two, 8 oz. cups of coffee) per day. To help you determine how much caffeine you intake, some of the most common sources of caffeine are listed below with the average amount of caffeine they contain.
- brewed coffee (8 oz): 85 mg
- instant coffee (8 oz): 75 mg
- brewed or instant coffee (8 oz): 3 mg
- single shot of espresso (2 oz): 80 mg
- black tea (8 oz): 40 mg
- decaf black tea (8 oz): 4 mg
- green tea (8 oz): 40 mg
- dark, semi-sweet chocolate (1 oz): 20 mg
Now that we understand more about how much caffeine we’re consuming, let’s talk about what it does to our bodies.
One of the most commonly known facts about caffeine is that it has addictive qualities. Recognizing caffeine’s effects on the body can help us better understand why. Caffeine is a stimulant that affects the central nervous system. It causes increased neuron firing in the brain, which tricks the pituitary gland into thinking there is an emergency and causes the adrenal glands to release adrenaline. Caffeine also increases dopamine (the neurotransmitter that is affected by highly addictive drugs) levels in the brain, which may be what causes it’s addictive properties.
While regular caffeine use can cause a mild physical dependence, it certainly doesn’t threaten your physical, social, and economic health the way highly addictive drugs do. However, if you regularly consume caffeine and stop doing so abruptly, it is likely you will experience some withdrawal symptoms. These will often last a day or more, especially if you consume more than two cups of coffee a day, and may include: headache, fatigue, irritability, anxiety, mild depression, and difficulty concentrating.
While caffeine withdrawal may make you uncomfortable for a few days, the symptoms are nowhere near as severe as those experienced when withdrawing from alcohol and other street drugs, which is why most experts don’t consider caffeine addiction serious or especially harmful. However, if you need your morning cup of coffee to avoid headaches and irritability this may be a sign you should cut back. This doesn’t mean you have to quit drinking coffee, soda, or tea entirely though. Switching to decaf coffee and soda and herbal teas are good ways to enjoy your favorite beverages without getting too much caffeine.
Though caffeine addiction is not extremely dangerous, excessive caffeine consumption can have consequences. High doses of caffeine can cause headaches. Caffeine can also cause you to feel jittery, skittish, excitable, or anxious. Too much caffeine may make it difficult to concentrate and may exacerbate feeling of stress. While these effects are mild, certain caffeinated beverages may pose more serious health risks.
For example, the acid in coffee can upset the stomach and irritate ulcers. And many coffee and energy drinks have a lot of sugar and calories, which can contribute to conditions such as obesity and type 2 diabetes. In order to enjoy your caffeine fix safely, it is best to moderate your intake of sugary coffee and energy drinks. It also helps to be informed about how all the calories from flavored syrups, whipped cream, and milk add up. So, if you frequent Starbucks, make sure to check out nutritional information for your favorite drinks online. Try asking for skim milk, light syrups, less pumps of syrup, and no whipped cream to reduce sugar and calories.
Though caffeine itself can cause some mild discomfort, studies show that caffeine consumption does not lead to any serious health risks. The truth is, moderate amounts of caffeine, meaning 300 mg (about 3 cups of coffee) or less, have been proven to have no negative health effects on most healthy adults. High levels of caffeine intake (consumption of 744 mg per day or more), can cause increased calcium and magnesium loss in urine. But, this does not increase your risk of bone loss, if you are getting enough calcium on a daily basis. The calcium loss from drinking one cup of coffee can be offset by adding just 2 tablespoons of milk. Elderly people should limit their intake of caffeine, however, as their metabolisms may be more sensitive to its effects. Additionally, some research has shown links between calcium intake and the risk of hip fracture in older individuals.
For those who are sensitive to caffeine, it is normal for consumption to cause a minor, temporary rise in blood pressure and heart rate. But, many studies show there is no definite link between caffeine intake and high cholesterol, irregular heart rhythms, or increased risk of heart or cardiovascular disease. There is little research to determine whether caffeine increases the risk of stroke for people who have high blood pressure, however, so if you do have high blood pressure it is best to discuss with your doctor how much caffeine is safe for you.
Furthermore, a number of studies have shown that there is no relationship between cancer and caffeine. And some studies even indicate that caffeine may help prevent certain types of cancer, and other serious health conditions. A study conducted in Mexico and published in The Journal of Physical Chemistry B, found that caffeine, an antioxidant, actually helps fight damaging free radicals (molecules in the body that can lead to disease because they attack and harm healthy cells), especially those associated with Alzheimer’s and heart disease. Another study published in Neurology‘s online edition, showed that people who regularly use caffeine are less likely to develop Parkinson’s disease. This study also showed that caffeine can modestly improve the severity of symptoms, such as amount of stiffness and speed of movement, for people who already have Parkinson’s disease. Also, limited evidence has also shown that caffeine may reduce the risk of liver disease, colorectal cancer, type 2 diabetes, and dementia.
Many studies also show that low amounts of caffeine (one cup of coffee a day) are not actually harmful to women who are trying to get pregnant, as was once believed. These studies show that drinking one cup of coffee a day or less has no link to difficulties with conception, miscarriage, birth defects, premature birth, or low birth weight. However, the March of Dimes does recommend that pregnant women drink less than 200 mg of caffeine a day because limited studies have shown that women who consume high levels of caffeine have a higher rate of miscarriage.
Studies also show that caffeine does not actually cause dehydration. While it does act as a mild diuretic, the fluid you consume while drinking a caffeinated beverage cancels out the fluid lost during urination. Caffeine is also often linked to insomnia, which is also not entirely accurate. Since caffeine is processed by the body very quickly, 8-10 hours after consuming caffeine the liver has already eliminated 75% of it. This means, for most people having a cup of coffee or two in the morning isn’t going to keep them from falling asleep later that evening.
However, caffeine consumed later in the day can affect sleep. For most people, avoiding caffeinated foods and beverages at least 6 hours before bedtime will ensure that sleep is not disrupted. Some people may be more sensitive though, depending on their regular caffeine intake and metabolism. In general, while caffeine will not cause insomnia, it is best not to drink excessive amounts of caffeine if you tend to have trouble sleeping.
Ultimately, studies prove that caffeine does not cause any real health risks and could even potentially have certain important health benefits. However, due to caffeine’s mildly addictive qualities and potential exacerbation of certain age and health related conditions, as with any “drug,” when it comes to caffeine, moderation is key.