18 Caffeine Health Benefits and Side Effects
Caffeine is the world’s most widely consumed psychoactive drug. It boosts physical and psychological performance and may decrease the risk of type 2 diabetes, Parkinson’s disease, Alzheimer’s disease, and much more. However, there are significant drawbacks to think about. Read on to learn the caffeine benefits, side effects, and interactions.
What is Caffeine?
For normal individuals, coffee or tea is the main source of caffeine. Coffea arabica and Coffea canephora (Robusta) are two types of plants that make coffee beans. The Camellia sinensis leaves are traditionally used for black, white, green, and white teas.
Although coffee and tea both contain caffeine, they can have different impacts on our health. This could possibly be due to their various amounts of caffeine, polyphenols, or alternative components.
Caffeine is absorbed around the world because of its beneficial effects on energy, physical and psychological performance, endurance, and mood. A lot of individuals praise its ability to keep them awake and focused on their jobs. Still, its prolonged use includes certain drawbacks worth attention.
- Boosts physical and psychological performance
- Relieves soreness and pain
- Protects the liver
- Helps prevent Parkinson’s and Alzheimer’s
- Helps prevent diabetes and kidney stones
- May encourage weight loss
- May cause tolerance and dependence
- Withdrawal can be exceedingly unpleasant
- May worsen anxiety and insomnia
- Increases blood pressure and heart rate
- May contribute to glaucoma at elevated doses
How does this Work?
Since caffeine’s structure is like adenosine, it can block adenosine receptors (mainly A1 and A2A). It raises the activation of the sympathetic (fight-or-flight) nervous system, which leads to stimulatory effects.
Consumers may feel more energized and alert as a result of caffeine blocking A1 receptors. This also causes heart-pounding impacts.
Caffeine binds to phosphodiesterase receptors and blocks phosphodiesterase action. As less phosphodiesterase receptor molecules become accessible, cAMP can’t bind to the receptors and it accumulates in the cells. This creates effects like vasodilation (widening of blood vessels), and fat oxidation (breakdown).
Caffeine Health Benefits
Caffeine is a part of distinct FDA-approved drugs for migraine headaches, together with acetaminophen, aspirin, sumatriptan, diclofenac, and others.
Based on its proven efficacy, caffeine can also be FDA-approved for easy (tension) headaches and also the prevention of postoperative headaches.
Paradoxically, headache is one of the most common symptoms of caffeine withdrawal, which can be a limit for its long term use.
2) Attention and Alertness
Multiple clinical evaluations have confirmed the potential of caffeine to improve mental alertness in low-to-moderate dosages (40-300 mg). The effects were more conspicuous in non-regular consumers and through sleep deprivation.
In a study of 36 participants, caffeine was shown dose-dependent effects on alertness and attention. When individuals who usually do not drink caffeinated goods have large doses of caffeine, then they had higher growth in brain functioning. Regular and tolerant users might still feel exactly the same consequences but to a smaller scope.
A lack of sleep can cause delays in response times. In an analysis of 20 sleep-deprived participants, a total daily dose of 800 mg of caffeine helped improve reaction speed and precision.
In 1 study, twelve young adults either had adequate sleep (9 hours) or a lack-of-sleep (4 hours). 100 milligrams of caffeine improved both classes’ coordination, judgment, memory, and response time through a driving task.
But some reviews have shown the tolerance for its stimulant effects, abuse potential, and possible toxicity that comes with higher doses.
3) Physical Performance
A comprehensive clinical review outlined 21 meta-analyses on caffeine and physical performance. A massive body of evidence indicates that”caffeine ingestion improves exercise performance in a wide selection of exercise tasks.” It revealed beneficial effects on:
- Muscle endurance
- Muscle strength
- Aerobic endurance
- Anaerobic power
Caffeine particularly helps anaerobic exercises like jumping or sprinting. This effect may arise from its anti-fatigue results and by improving endurance, physical strength, and power output.
When caffeine waits for fatigue, the body’s muscles may contract more forcefully. Folks may exercise more and eventually increase their training volume or overall work. Aerobic exercise such as running, jogging, cardio workout, swimming, and cycling may benefit the most from improved training volume.
4) Parkinson’s Disease
Caffeine is neuroprotective and may prevent nerve cell degeneration, which occurs in Parkinson’s.
Furthermore, by inhibiting adenosine receptors, it enhances mobility and motor functions in Parkinson’s patients.
In a study of 61 Parkinson’s patients, 100 milligrams of caffeine twice per day for 3 weeks decreased motion slowness (bradykinesia). But, it had no other effects on Parkinson’s symptoms.
In 1 study, out of 430 healthy subjects, those who consumed caffeinated coffee had a lower risk of developing Parkinson’s disease. It even reduced the risk in those genetically predisposed to develop the illness.
Additionally, in a study of 29,000 participants, both habitual coffee and tea drinkers had a lower risk for Parkinson’s.
5) Dementia and Alzheimer’s Disease
In a long-term analysis of 1,400 people, drinking 3 to 5 cups of java every day at midlife could decrease dementia or Alzheimer’s disease (AD) risk by about 65% during their elderly years.
In one review, coffee had a positive impact on brain function. Moderate caffeinated coffee consumption decreased the risk of dementia and AD later in life. But, carbonated tea had no consequences.
In mice, caffeine suppressed amyloid-beta generation. Amyloid-beta contributes to brain inflammation and the onset of Alzheimer’s disease.
6) Liver Disease
Caffeine is associated with a lower risk of liver fibrosis (scar tissue in the liver). In a study of 306 patients with a fatty liver disorder, individuals who drank caffeinated coffee had less severe liver scarring than the ones who didn’t drink caffeinated coffee.
In a cross-sectional study of 910 veterans with chronic hepatitis C, a minimum of 100 mg of caffeine every day reduced the odds of liver tissue fractures.
In addition, in a survey of 177 liver biopsy patients, caffeine consumption was correlated with less severe liver tissue scarring. 2 cups of coffee daily helped reduce the severity of tissue scarring.
An analysis of 274 cirrhosis cases and 458 healthy individuals found that caffeinated coffee avoided liver cirrhosis (chronic liver damage). However, ingestion from sources other than java (such as energy or tea drinks) didn’t demonstrate the same advantages.
According to a review of 20 studies with 7,238 participants, caffeine may marginally but significantly improve the efficacy of acetaminophen, ibuprofen, and other painkillers.
8) Weight reduction
Many supplements are encouraged to stimulate weight loss, but none of them has been endorsed by strong clinical evidence and accepted by the health authorities. A healthy, calorie-controlled diet and increased physical activity remain the only proven strategies for weight control.
A combination of ephedrine and caffeine enhanced fat burning and weight reduction and reduced blood lipids in five trials of over 500 participants.
Nevertheless, pure ephedrine and Ephedra-based goods are prohibited by the FDA due to their high abuse potential and negative effects on heart health.
Caffeine remained a popular ingredient in over-the-counter fat burning supplements. It may boost energy use and enhance metabolic rate, which can help stop weight gain.
A meta-analysis published in 2019 included 13 clinical trials of 606 participants. The authors concluded that”caffeine intake may encourage weight, BMI and body weight reduction”.
By breaking down stored fat, caffeine reveals possible gains in weight reduction management. In a study of 2,100 participants, the ones who drank 2 to 4 cups of caffeinated coffee a day were more successful at shedding weight than individuals who did not.
In a study of 95 healthy young adults, moderate doses of caffeine (200 mg) increased memory performance. Even though the results were not important, high to moderate caffeine users had increased memory recall compared to low users.
In a different study, 140 young adults participated in 2 experiments. The participants that have caffeinated coffee in the morning had significantly superior performances on a memory recall test in the early morning, but not in the late day.
One review concluded that caffeine was inconsistent in its effects on memory. It was very beneficial in improving memory during easy jobs, but not complicated ones.
According to a review of clinical studies, caffeine can help to open the airways and relieve asthma symptoms such as coughing, coughing, and breathlessness.
The result is similar to theophylline, a frequent asthma drug. Theophylline and caffeine are very similar in structure, but caffeine effects are short-lived and last only around 4 hours.
11) Cancer Prevention
Mouth and Throat Cancer
A 26-year observational study analyzed nearly 1 million people to examine the association between ingestion and oral/pharyngeal (mouth and throat) cancer.
There has been an association between high caffeinated coffee intake and decreased risk of oral cancer. Individuals who consumed 4 to 6 cups of caffeinated coffee daily had up to two times lower cancer rates.
Within an observational trial of 489,706 men, there was an inverse association between caffeinated coffee and colon cancer rates.
On the other hand, there was no link between caffeine and rectal cancer risk in a study of 120,000 physicians.
In a study of 450,000 subjects, caffeinated coffee drinkers had a lower risk of developing melanoma (skin cancer) than people who did not drink caffeine.
A meta-analysis of research with non-melanoma skin cancer also found the protective effects of coffee and caffeine. Their regular intakes were associated with 14% and 18% lower cancer rates, respectively.
An overview of 9 observational research found 43% reduced levels of liver cancer associated with the ingestion of two cups of caffeinated coffee daily.
It’s worth mentioning that the above results come from observational studies. Furthermore, other beneficial coffee ingredients may have contributed to the results. Well-designed clinical trials are required to assess the potential anticancer effects of caffeine.
12) Type 2 Diabetes Prevention
In an observational study of almost 90,000 healthy girls, moderate caffeinated coffee consumption lowered the risk of type 2 diabetes in middle-aged and younger women.
Another evaluation of 8 trials also showed that drinking caffeinated coffee is associated with a reduced risk of type 2 diabetes.
13) Kidney Stones
In a 20-year analysis of 217,883 healthy participants, high caffeine intake was associated with reduced rates of kidney stones.
Caffeine increases urinary excretion of calcium, which might cause kidney stone formation. At the exact same time, the higher intake of caffeine diluted urine and reduced kidney stone’s risk.
No legitimate clinical evidence supports the use of caffeine for some of the conditions within this part. Below is an overview of up-to-date animal research, cell-based research, or low carb clinical trials which should spark an additional investigation. But, you shouldn’t interpret them as supportive of any health advantage.
14) Mood and Mental Health
In a large cohort study of 43,599 men and 164,825 women, individuals who consumed brewed coffee had a lower rate of suicide. This might be due to caffeine’s ability to increase dopamine.
However, higher amounts (600 mg) can increase tension and anxiety, which can negatively affect mood.
The effects of caffeine on depression are also conflicting: You can find studies demonstrating both increased and decreased rates related to caffeine ingestion.
The explanation for conflicting results may lie in caffeine’s abuse tolerance and potential to both adverse and beneficial effects. Further research is warranted.
15) Skin Protection
The protective effects against skin cancer probably stem from caffeine antioxidant properties that protect skin cells against UV radiation from sunlight exposure. Additionally, it is used in cosmetic products to prevent fat accumulation and cellulite formation.
In a report of 40 dermatitis sufferers, a topical cream containing 30% caffeine helped decrease redness, itchiness, scaling, and oozing.
More studies are needed to evaluate the skin-friendly effects of caffeine.
16) Erectile Dysfunction
An observational analysis of 3,700 men showed that people who drank 2 to 3 cups of caffeinated coffee daily had a lower chance of erectile dysfunction. While healthy, overweight, and men with high blood pressure experienced these benefits, caffeine did not help diabetic men.
In a prospective analysis of 6,500 women, individuals who consumed the maximum caffeine had the cheapest reported prevalence of tinnitus (ringing in the ears).
In a prospective study of 89,000 women, caffeinated coffee (although not tea) was associated with a lesser risk of gout.
Controlled clinical trials are needed to evaluate the above-mentioned benefits of caffeine found in observational research.
According to the available clinical signs, caffeine supplementation may not assist with:
- Atrial fibrillation (irregular heartbeat)
- ADHD in kids
Effects on Inflammation
In a study of 47 habitual coffee drinkers, drinking caffeinated coffee is associated with a decrease in inflammation mark (IL-18).
Additionally, in a different analysis of 1,390 healthy girls and women who have type 2 diabetes, those who drank caffeinated coffee had lower inflammatory markers (E-selectin and CRP) levels.
Nonetheless, in a study of blood cells from 8 healthy individuals, 165 milligrams of caffeine supplementation decreased inflammation markers (IL-6, IL-8, PGE2, PGA2, PGD2, etc.) in certain blood samples while it improved them in other people.
In a study of 33 athletes, caffeine supplementation caused higher levels of inflammatory cytokines (IL-6 and IL-10) after exercise. It improved the body’s inflammatory response to exercise.
Caffeine increases inflammation in response to psychological stress. In a study of 85 healthy areas, habitual caffeinated coffee, but not java, consumption was associated with increased blood vessel inflammation.
Further clinical research should throw more light on the contradictory effects of caffeine.
Limitations and Caveats
Although caffeine appears to get promising health benefits, most of the studies only showed relationships between its consumption and health improvement (causal research is lacking).
Additionally, since many research utilized java because of their source of caffeine, it is likely that other substances contributed to its effects.
Caffeine Side Effects
When utilized in adequate amounts, caffeine is likely safe for healthy individuals. However, insensitive people, it can cause some unpleasant side effects such as:
- Increased urination
- Muscle twitching
- The rambling flow of thought and speech
But most of caffeine side effects tend to decrease with prolonged ingestion and endurance.
Caffeine is a psychostimulant drug. Since its effects vary among individuals, people alter their needs in accordance with their level of tolerance. By way of instance, if you always drink a cup of java in the morning, going a day or two with no regular fix is tough for the body and mind.
Caffeine withdrawal can be a serious reaction of the body to the lack of this stimulant, with symptoms such as:
- Lack of attention
- Digestive issues
Those who take caffeine routinely, in any form, may build up a tolerance to different health effects, both beneficial and adverse.
The side effects of excessive caffeine ingestion include greater heart rate (tachycardia), restlessness, and nervousness. Should you’re feeling nervous and stressed, you should avoid it as well as glucose and other stimulants.
In a large cohort study of secondary school children, there was a positive correlation between caffeine and anxiety. High consumption of caffeine worsened stress, anxiety, and depression symptoms.
It is a well-known truth that caffeine can help with wakefulness. While this is a benefit for some people, it’s a problem for many who have sleep-related problems. Magnesium might interrupt the body’s natural hormone levels and wake-and-sleep cycles which encourage restful sleep.
If you suffer from insomnia, then you should just have carbonated beverages before noon or eliminate them completely.
4) Reduced Insulin Sensitivity
In a study of 12 male participants, high levels of caffeine reduced their insulin reactions.
In another study, high caffeinated coffee consumption temporarily diminished insulin sensitivity. A larger release of neurotransmitters (catecholamines) and free fatty acids, higher insulin secretion, or maybe less insulin clearance in the liver might have caused this decrease in insensitivity.
However, for many healthy people, caffeine should have no substantial impact on blood glucose levels.
5) Increased Blood Pressure
This effect is dependent on two factors: if the user generally drinks caffeine and if they have a family history of hypertension (elevated blood pressure).
A meta-analysis of 16 research showed that 410 milligrams of caffeine every day elevated the risk for high blood pressure, even in healthy people. However, the ingestion of caffeine through coffee only had a little influence on blood pressure.
New users might experience higher spikes in blood pressure, but the consequences subside soon after (about 4 days). However, individuals with hypertension or those at risk should consume it with care.
6) Increased Cholesterol
In a study of 30 adults, caffeine has been associated with substantial growth in total blood cholesterol and LDL (bad) cholesterol.
Long-term consumption of caffeinated coffee may alter fat distribution within the body and lead to atherosclerosis in some cases.
Insulin increases the blood level of adrenaline. This hormone can raise blood pressure, contractility of the heart, and heart rate (tachycardia). The result is more pronounced in those who don’t frequently consume it or at those who take high doses.
8) Blood Clotting
Caffeine blocks adenosine A2a receptors and causes blood vessels to constrict.
In a study of 33 healthy subjects, a high dosage of caffeine enhanced blood platelet count and clotting, whilst exercise improved this effect even more. Luckily, this response may be desensitized after prolonged use.
In mice, when it binds to A2a receptors, caffeine may induce blood clotting.
9) Glaucoma (In High Doses)
In a cohort study of more than 120,000 healthy patients, the participants whose total caffeine consumption was significantly more than 500 mg daily had greater glaucoma rates (elevated pressure in the eye) than people who consumed less than 125 mg daily.
In a different cohort analysis of 3,600 patients, habitual caffeinated coffee drinking has been associated with high eye pressure and nausea.
Caffeine Drug and Substance Interactions
In a study of seven participants, fluvoxamine, an SSRI used to treat OCD and depression, inhibited CYP1A2, which is the most important enzyme which breaks down caffeine. Taking Fluvoxamine and caffeine together may impair caffeine elimination, possibly causing adverse effects.
Propranolol is a beta-blocker that can help treat cardiovascular disease, higher blood pressure, and chest pain (angina). Anti-anxiety effects of beta-blockers can be reduced by a high dosage of caffeine, as caffeine raises anxiety. Caffeine may interact with propranolol, raising blood pressure.
Athletes normally use creatine to boost their exercise performance, including strength and endurance. However, caffeine consumption can lessen the creatine’s effectiveness. In a variety of studies, concurrent use of caffeine and creatine caused stomach issues and dehydration.
Combining caffeine and alcohol is very common from the nightlife because a lot of people add energy drinks to their alcoholic drinks.
Both caffeine and alcohol block adenosine receptors. The receptors assist mediate both their unwanted effects, such as sleepiness, lack of muscular coordination, and nervousness. So when you combine them, they block the A1 receptors and can prevent you from detecting the side effects.
Also, when caffeine blocks A2A receptors, it can bring about the addictive effects of alcohol.