According to scientists at the FDA, caffeine can be part of a healthy diet for most people, but too much caffeine may pose a danger to your health. Depending on factors such as body weight, medications you may take, and individual sensitivity, “too much” can vary from person to person. Caffeine is a natural chemical with stimulant effects. It is found in coffee, tea, cola, cocoa, guarana, yerba mate, and over 60 other products.
Caffeine works by stimulating the central nervous system, heart, muscles, and the centers that control blood pressure. Caffeine can raise blood pressure, but might not have this effect in people who use it all the time. Caffeine can also act like a “water pill” that increases urine flow.
People most commonly use caffeine for mental alertness, headache, migraine, athletic performance, memory, and obesity. It is also used for asthma, gallbladder disease, ADHD, low blood pressure, depression, and many other conditions, but there is no good scientific evidence to support most of these other uses.
Caffeine products sold in very concentrated or pure forms are a health concern. People can easily take doses that are much too high by mistake. It’s illegal in the US for these products to be sold to consumers in bulk. Taking caffeine, within limits, is allowed by the National Collegiate Athletic Association (NCAA). Urine concentrations over 15 mcg/mL are prohibited.
How much caffeine is in the regular coffee beans?
Coffee is the biggest dietary source of caffeine. You can expect to get around 95 mg of caffeine from an average cup of coffee. However, this amount varies between different coffee drinks and can range from almost zero to over 500 mg.
What Factors Affect Caffeine Content?
The caffeine content of coffee depends on many factors, such as:
Type of coffee bean:
There are many varieties of coffee beans available, which may naturally contain different amounts of caffeine.
Lighter roasts have more caffeine than darker roasts, although the darker roasts have a deeper flavor.
Type of coffee:
The caffeine content can vary significantly between regularly brewed coffee, espresso, instant coffee and decaf coffee.
“One cup of coffee” can range anywhere from 30–700 ml (1–24 oz), greatly affecting the total caffeine content.
How Much Caffeine Is in a Cup of Coffee?
The main determinant of caffeine content is the type of coffee you are drinking.
Brewing is the most common way to make coffee in the US and Europe. Also known as regular coffee, brewed coffee is made by pouring hot or boiling water over ground coffee beans, usually contained in a filter. One cup of brewed coffee (8 oz) contains about 70–140 mg of caffeine or about 95 mg on average.
Espresso is made by forcing a small amount of hot water, or steam, through finely ground coffee beans. Although espresso has more caffeine per volume than regular coffee, it usually contains less per serving, since espresso servings tend to be small. One shot of espresso is generally about 30–50 ml (1–1.75 oz), and contains about 63 mg of caffeine. A double shot of espresso therefore contains roughly 125 mg of caffeine.
Many popular espresso coffee drinks are made from espresso shots mixed with varying types and amounts of milk. These include lattes, cappuccinos, macchiatos and Americanos. Since the milk does not contain any additional caffeine, these drinks contain the same amount of caffeine as straight espresso. A single (small) contains about 63 mg of caffeine on average, and double (large) contains about 125 mg.
Instant coffee is made from brewed coffee that has been freeze-dried or spray-dried. It is generally in large, dry pieces, which dissolve in water. To prepare instant coffee, simply mix one or two teaspoons of dried coffee with hot water. There is no need for any brewing. Instant coffee usually contains less caffeine than regular coffee, with one cup containing roughly 30–90 mg.
Decaf Coffee drinks
Although the name may be deceiving, decaf coffee is not entirely caffeine free. It may contain varying amounts of caffeine, ranging from 0–7 mg per cup, with the average cup containing 3 mg. However, some varieties may contain even higher amounts of caffeine, depending on the type of coffee, method of decaffeination and cup size.
Are Caffeinated Beverages Really Bad For You?
Each day, billions of people rely on caffeine to wake up, or to get through that night shift or an afternoon slump. In fact, this natural stimulant is one of the most commonly used ingredients in the world. Caffeine is often talked about for its negative effects on sleep and anxiety. However, studies also report that it has various health benefits.
May improve mood and brain function
Caffeine has the ability to block the brain-signaling molecule adenosine. This causes a relative increase in other signaling molecules, such as dopamine and norepinephrine. This change in brain messaging is thought to benefit your mood and brain function.
One review reports that after participants ingested 37.5–450 mg of caffeine, they had improved alertness, short-term recall, and reaction time. In addition, a study linked drinking 2–3 cups of caffeinated coffee (providing about 200–300 mg caffeine) per day to a 45% lower risk of suicide.
May boost metabolism and fat burning
Because of its ability to stimulate the central nervous system, caffeine may increase metabolism by up to 11% and fat burning by up to 13%. Practically speaking, consuming 300 mg of caffeine per day may allow you to burn an extra 79 calories daily. This amount may seem small, but it’s similar to the calorie excess responsible for the average yearly weight gain of 2.2 pounds (1 kg) in Americans.
However, a 12-year study on caffeine and weight gain noted that the participants who drank the most coffee were, on average, only 0.8–1.1 pounds (0.4–0.5 kg) lighter at the end of the study
May enhance exercise performance
When it comes to exercise, caffeine may increase the use of fat as fuel. This is beneficial because it can help the glucose stored in muscles last longer, potentially delaying the time it takes your muscles to reach exhaustion. Caffeine may also improve muscle contractions and increase tolerance to fatigue. Researchers observed that doses of 2.3 mg per pound (5 mg per kg) of body weight improved endurance performance by up to 5% when consumed 1 hour before exercise.
May protect against heart disease and diabetes
Despite what you may have heard, caffeine doesn’t raise the risk of heart. In fact, evidence shows a 16–18% lower risk of heart disease in men and women who drink between 1–4 cups of coffee daily (providing approximately 100–400 mg of caffeine) Other studies show that drinking 2–4 cups of coffee or green tea per day is linked to a 14–20% lower risk of stroke.
One thing to keep in mind is that caffeine may slightly raise blood pressure in some people. However, this effect is generally small (3–4 mmHg) and tends to fade for most individuals when they consume coffee regularly
How addictive is caffeine consumption?
Most adults in the U.S. use caffeine, whether in coffee, soda, energy drinks, or chocolate. Many are also familiar with the effects of suddenly drinking less coffee than usual: tiredness, headaches, insomnia, and other symptoms. And many people talk about being “addicted” to their morning coffee or energy drink! But is caffeine truly addictive? It’s all about the dopamine
The world’s caffeine obsession can be described as a “dependency” (because when you have less of it, you go through a mild “withdrawal,” with the symptoms listed above), but it is not an addiction. It is true that—like many drugs—caffeine enhances dopamine signaling in the brain.
Dopamine is a chemical that helps control movement, motivation, and emotions, so enhanced dopamine signaling makes a person feel more awake and alert. Because caffeine produces that alert feeling, it’s classified as a stimulant. But wait—some prescription drugs and the dangerous drug methamphetamine (“meth”) and MDMA (ecstasy or Molly) are also types of stimulants.
So what’s the difference?
While caffeine produces a small rise in dopamine, it does not cause the large surge that unbalances the reward circuits in the brain and is necessary for an addiction. So even though the word “addiction” is often used casually, caffeine is not addictive (scientifically speaking).
Many packaged foods, including beverages and dietary supplements containing caffeine, voluntarily provide information on the label as to how much caffeine they contain. Consumers should take care when consuming for the first time a new packaged food containing added caffeine if the amount of caffeine in the food is not declared on the label. A moderate caffeine consumption is never bad.