Caffeine is one of the best ways to start the day, as it energizes us in the morning. Caffeine benefits include boosting the central nervous system and preventing drowsiness. Drinking a steaming cup of coffee or tea stimulates our senses and is good for our health. Caffeine has psychoactive properties and is a common ingredient in beverages, chocolates, and even decaffeinated products. It contains antioxidants, flavonoids, and polyphenols, so it does much more for the body. Interested in learning how it works? Read on to learn about the benefits of caffeine, dosage, potential side effects, and common myths.
In This Article
How Caffeine Works
Caffeine has an immediate effect and gets absorbed into the blood in just 15 minutes. It is a psychoactive drug, meaning it can influence the brain and nervous system’s function. Caffeine activates different neuronal pathways by altering the release of neurotransmitters (signaling molecules released by the neurons). Consuming caffeine blocks adenosine (an inhibitory neurotransmitter that makes you feel tired and promotes sleep) to reduce fatigue and keep you alert (1), (2).
Coffee, tea, carbonated, and energy drinks contain high amounts of caffeine. Scroll down to find out the amount of caffeine content in different beverages.
What Drinks Contain Caffeine?
Here is the list of the most common sources of caffeine (3):
Sources Of Caffeine
Caffeine Content (per 8 ounces)
Plain brewed coffee
In addition, dark chocolate contains 5,035 mg of caffeine. Consuming caffeine has several benefits. Check them out.
Health Benefits Of Caffeine
1. Improves Brain Function
Caffeine is a central nervous system stimulant and can increase energy metabolism in the brain (4). It reduces cognitive decline, increases alertness, improves brain function, minimizes the risk of depression, and helps to focus and concentrate (5), (6), (7). Caffeine enhances long-term memory, and its regular consumption in limited amounts can reduce the risk of stroke, dementia, Alzheimer’s disease, and Parkinson’s disease (8), (9), (10), (11), (12).
2. May Help With Weight Loss
Caffeine intake may support weight loss, reduce BMI and body fat, and help manage optimal body weight (13), (14). A study conducted by Maastricht University, Netherlands, found that high caffeine intake promoted weight loss through fat oxidation and thermogenesis (15). In addition, it can prevent weight regain and be used as an alternative treatment for weight loss (16). Another study conducted on 18,417 men and 39,740 women found that increased caffeine intake may reduce long-term weight gain (17).
3. Enhances Exercise Performance
Caffeine supplements (about 2-9 mg per day) can enhance exercise performance (18),(19). In addition, it is used as an ergogenic aid that enhances endurance and performance during prolonged exercise. A study conducted by the University of Birmingham, United Kingdom, found that consuming 5mg/kg caffeine one hour before exercise could improve exercise performance(20), (21).
Caffeine increases blood flow to active muscles, thereby increasing oxygen delivery. This allows your body to burn fat at a faster rate while exercising. Caffeine can also increase endurance and help prevent muscle cramping.
4. Improves Heart Health
Consuming caffeinated beverages like coffee is associated with a decreased risk of cardiovascular diseases (22), (23). A study conducted by the University of Singapore and National University Health System, Singapore, has found that coffee can lower the risk of stroke and heart failure (24). Moderate coffee consumption lowers the risk of coronary heart disease in women (25).
5. Prevents Diabetes
A study evaluated the link between coffee and the risk of type 2 diabetes. Researchers found that drinking more than a cup of coffee lowered the risk of type 2 diabetes (26 ). With every 200 mg per day of caffeine intake, the risk of diabetes drops by 12-14%. A review published in the Journal of Traditional and Complementary Medicine suggests that coffee consumption lowers the risk of type 2 diabetes (27),(28).
6. Protects Against Cancer
Caffeine has anticarcinogenic properties and can help protect against certain cancers, including colon, oral, prostate, breast, and skin cancers. It increases large bowel mobility and can effectively inhibit the risk of colorectal cancer (29), (30).
Caffeine contains antioxidants, anti-mutagen, and diterpenes, which may also reduce the risk of oral cancer. It has antiproliferative and antimetastatic properties that help inhibit the growth of prostate cancer cell lines. In addition, the chemoprotective activity of caffeine reduces the risk of nonmelanoma skin cancer (31), (32), (33).
An animal study found that eye drop preparation containing 72 mM caffeine inhibited cataract formation and showed a potential benefit in preventing diabetic cataracts (34). In addition, trigonelline, a bioactive in caffeine, has protective effects against kidney stone formation (35).
Intake of caffeine in limited quantities is safe. But how much should you drink? Find out this in the following section.
How Much Caffeine Is Too Much?
About five cups of coffee (400 mg daily) is considered safe for healthy adults (9). However, pregnant women should limit their caffeine intake to 200 mg per day (36). Excess caffeine intake has several side effects.
What Are The Side Effects Of Caffeine?
- Unstable bladder
- Gastric irritation
- Risk of miscarriage and fetal growth restriction
- Cardiac abnormality
Melissa Mitri, MS, RDN, says, “Some people are more sensitive to caffeine than others, and so it is important to know the signs that your body is not responding well to it.” Excessive caffeine can spike blood pressure, increase arterial stiffness, and increase the risk of chronic headaches (39), (40).
Caffeine consumption before pregnancy increases the risk of miscarriage and may lead to a progressive decrease in fertility levels (41), (42). In addition, caffeine consumption (10 or more cups per day) during lactation can affect the infant, hamper sleep, and make them jittery and fussy (37). It can also interact with over-the-counter and prescription medications (43).
Pregnant women who consume coffee may experience premature birth. This happens due to the high levels of caffeine that are present in coffee. The caffeine content in coffee increases the risk of preterm labor by increasing uterine contractions.
Babies born to mothers who consume coffee during pregnancy have a lower weight than babies born to mothers who do not drink coffee. This is because caffeine causes an increase in blood pressure and heart rate. These changes result in a low oxygen supply to the fetus.
Caffeine has its benefits and recognized risks. But most often, it is misunderstood as a dangerous stimulant. In the next section, we have busted several myths associated with caffeine.
Myths Associated With Caffeine
Myth 1. Caffeine Is Addictive
No. It is not as caffeine cannot stimulate the pathways in your brain that are related to addiction. Some people may experience drowsiness, headaches, lethargy, or fatigue if they suddenly stop consuming caffeine (44). However, these usually last for a day or two. So, if you are trying to ditch caffeine, do it gradually to avoid these symptoms.
Myth 2. Caffeine Increases The Risk Of Heart Disease
It may increase blood pressure in people sensitive to caffeine, but not in healthy adults. Hence, if you have any heart problems or hypertension, please consult your doctor about your caffeine dosage.
Myth 3. Caffeine Is A Diuretic
There is no research to prove this claim. However, caffeine consumption has been associated with increased urine frequency and volume, which causes water and electrolytes loss. However, caffeine is not directly linked to fluid loss.
- Caffeine can block adenosine, a neurotransmitter that makes one feel tired and sleepy.
- Caffeine enhances exercise performance, aids in weight loss, improves brain function, and reduces cancer risk.
- 400 mg of caffeine per day is considered a safe range.
Caffeine, one of the major compounds in coffee, energizes our bodies. This stimulant, in moderation, activates our nervous system and keeps us awake. Caffeine benefits range from better cognitive function to enhanced exercise performance. It may also help manage diabetes and aid weight loss. You can reap these benefits by consuming caffeinated teas, coffees, and energy drinks. However, excess caffeine intake can lead to sleeplessness, gastric irritation, or anxiety. If you experience any adverse effects, limit its use and seek medical advice.
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- Reduction by coffee consumption of prostate cancer risk: Evidence from the Moli-sani cohort and cellular models
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- Effectiveness of topical caffeine in cataract prevention: Studies with galactose cataract
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