Do we think coffee benefits we get when drinking it is something good for our brain or bad or neutral? What does the actual caffeine do and what are the risks?
Milos Pokimica
Written By: Milos Pokimica
Medically Reviewed by: Dr. Xiùying Wáng, M.D.
Updated May 29, 2023Do we think caffeine is something good for our brain or bad or neutral? There is much talk about coffee benefits but coffee benefits are also just one side of the coin. Coffee is also associated with some health risks that people usually just ignore. The real question is do we think that coffee benefits outweigh the associated risks?
So far research has no evidence to associate a link between coffee and an increased risk of heart disease or cancer. Some of the studies found decreased overall mortality by the same small amount, and some others found that it does the opposite. If we take an average conclusion from them, it will be approximately very small or no significant effect on longevity.
So are there any risks associated with the coffee benefits we so much desire?
Coffee seems to increase cognitive function and reduce the risk of depression. The potential coffee benefits also include protection against neurodegenerative diseases, improved asthma control, and lower risk of select gastrointestinal diseases. So did we find our amphetamine-like drug free of charge?
Coffee does have a high concentration of antioxidants providing cells protection from oxidative stress and inflammation. It is the bean after all. However, we can get other nontoxic beans to get all of the benefits that coffee bean has, and we should not confuse the coffee benefits as unique. Most antioxidant-rich foods will have the same effect.
When people talk about coffee benefits, they tell half-truths when insinuating that it is the benefit of that bean only and that we would not have similar benefits if we eat another type of bean. For example, cocoa beans have caffeine too but much more beneficial polyphenol antioxidants and much more health benefits so talking about the benefit of coffee is a little misleading.
To get to the truth, we should look into studies of pure caffeine and its effect on the body because that is the reason people drink coffee in the first place. We could get most of the coffee benefits with decaf too. It is caffeine that we need to investigate and not just use misleading science to justify our habit. It is the same story as alcohol, finding some benefits that we can also find in other food items without any unique special ability to just coffee beans so that we can justify our caffeine high.
What does the actual caffeine do?
We can take it in pills for example or in energy drinks. If we look at the chemical structure of caffeine, we will see that it is very similar to adenosine. Adenosine is a chemical in the brain that makes us sleepy. Whenever we are awake adenosine slowly accumulates in our brains. Adenosine binds to the receptors and in time slows our brain activity down. The longer we are awake, the more adenosine accumulates, and the more tired we feel. At some point, we will go to sleep. While sleeping concentration of adenosine declines and in the morning cycle begins again.
Because caffeine is similar to adenosine and acts as an adenosine receptor blocker in the brain, it will cancel natural brain chemistry making us feel more alert.
For individuals that regularly drink coffee in extensive amounts, our brains adjust by developing more adenosine receptors, so it takes more caffeine to elicit the same response. Having more adenosine receptors also means more adenosine makes its way into our brains so if we do not drink coffee, we will be more tired than in our regular normal state. In the morning, we will not be fully alert and during the day we will feel more tired if we did not drink our cup that day. It has a half-life of 6 hours meaning half of it will be gone in 6 hours so after 6 hours you will be feeling half of the effect. A couple of hours later it will be mostly gone, and we will need another cup.
Caffeine also stimulates the body to produce much more adrenaline than needed and that will end up in increased heart rate and anxiety.
Caffeine puts the body in a stressful state of fight and flight response leading to an increase in anxiety. People who are already overstressed and prone to panic attacks and other pro-anxiety conditions can have severe reactions with a tremor in their hands and cold sweats and heart palpitations from caffeine.
Caffeine also prevents dopamine from getting reabsorbed acting like cocaine in some sense leading to good feelings so by now we are in addictive behavior and have withdrawal symptoms. This dopamine effect is what makes coffee so addictive.
The reason why Coca-Cola puts caffeine in Coke is precisely because of this. Developing children’s brains is even more sensitive.
The lethal dose of caffeine is 150mg per kg of body mass. For a 70kg human, it is 14000mg caffeine. A cup of coffee on average has 150mg. This is not enough to kill but there is still one more fact that people tend to know little about. However, it is the one effect that is most important of them all. Adenosine also controls blood flow through the brain.
Caffeine produces cerebral vasoconstriction by antagonizing adenosine receptors.
Caffeine-induced cerebral vasoconstriction is well documented (Diukova et al., 2012). 250 mg of caffeine was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later around. The value of decreased blood flow in the brain goes from 20% for one small cup of coffee to 40% for 2 or 3 cups. Chronic caffeine use results in an adaptation of the vascular adenosine receptor system presumably to compensate for the vasoconstrictive effects of caffeine. This entire adrenaline bump and stress in the form of I am suffocating and dying, help me, I am your brain without the oxygen is what actually wakes you up because you are about to die literally. That is what your alert state is. Fight or flight stress response. And that is the real job of caffeine, to be one more neurotoxic chemical for defense against pests. If you drink coffee every day, the brain adapts and tries to compensate.
Nevertheless, there is a deadline for what the brain can compensate for. The limit is around 400 mg of caffeine a day. Drinking more than that will have vasoconstrictive effects even in people who are chronic caffeine addicts. What happens is that in expectation of one more coffee cup the brain is going to raise its internal brain pressure. So when we drink coffee, the pressure will drop from vasoconstrictive effects and become normal. If you skip that cup in the morning and skip again in the afternoon the buildup of internal brain pressure is going to give you a migraine headache. That is the reason why people who are trying to quit usually suffer from headaches that can last for days before their brains start to adapt again to new normalized conditions. There is more.
Caffeine is also frequently utilized as a pre-workout supplement, but caffeine may adversely affect and limit bloodstream flow to heart muscle throughout the exercise (Namdar et al., 2009).
When we do physical exercise blood flow has to increase in order to match the increased need for oxygen and caffeine may adversely affect this mechanism too and not just the blood supply to the brain. It restricts the blood flow in the heart muscle, but interestingly enough it did not affect blood flow while the study subjects were at rest. When the subjects took caffeine tablets and exercised the blood flow was significantly lower than normal. Blood flow should increase when people exercise due to the more significant demand for energy, but caffeine blocks receptors for adenosine in the heart muscle and blocks specific receptors in the walls of blood vessels. I would not recommend that anyone take caffeine as a pre-workout supplement or for any athlete to drink caffeine before sports. In the upper mentioned study after oral administration of caffeine 200 mg bicycle exercise-induced myocardial blood flow decreased by 11% in regular individuals. In subjects who have coronary artery disease decrease was 18% and by 25% in stenotic subjects (with cholesterol deposit narrowing of coronary arteries). Caffeine is a pesticide that kills insects and other plants. Neurotoxic poison. It has the purpose of defending the coffee plant.
The coffee plant is one of the rare plants in nature that commits suicide. Unique coffee benefits, suicide. The leaves and beans that fall from the coffee tree have caffeine, and they start to poison the ground. At first, they kill everything that lives in topsoil but as time passes and more and more leaves fall, and more concentration of caffeine in soil raises more of the root system of the coffee plant itself gets affected. Investigations regarding the use of caffeine on plants demonstrated that when the concentration of caffeine gets high enough it begins to distort plant cells and if it gets even higher the result is the death of the plant.
People usually try to drink coffee when they are already stressed enough. They have a lot of work, or they need to study for the exam so that constant stressful response full of adrenalin and cortisol up and downs is going to give them adrenal fatigue and overall stressful condition. Adrenal fatigue is not a real disease just a made-up term. It is not an accepted medical diagnosis. There is a real medical condition called Addison disease which causes adrenal insufficiency. Adrenal fatigue does not cause inadequate production of one or more of these hormones as a result of an underlying disease. Adrenal fatigue is a light form of adrenal insufficiency caused by chronic stress with rapid hormonal ups and downs during the day. It is not as much the insufficiency of the adrenal glands as it is an overall fatigue state caused by constant hormonal fluctuations. Trying to take Valium to relax or because you are unable to sleep is just going to make things worse.
How many people are complaining about their stressful lives?
The valid question should be how many of them are caffeine addicts?
Keep that in mind the next time you are eyeing that 2nd (or 10th) cup of joe.
References:
- Diukova, A., Ware, J., Smith, J. E., Evans, C. J., Murphy, K., Rogers, P. J., & Wise, R. G. (2012). Separating neural and vascular effects of caffeine using simultaneous EEG-FMRI: differential effects of caffeine on cognitive and sensorimotor brain responses. NeuroImage, 62(1), 239–249. https://doi.org/10.1016/j.neuroimage.2012.04.041
- Namdar, M., Schepis, T., Koepfli, P., Gaemperli, O., Siegrist, P. T., Grathwohl, R., Valenta, I., Delaloye, R., Klainguti, M., Wyss, C. A., Lüscher, T. F., & Kaufmann, P. A. (2009). Caffeine impairs myocardial blood flow response to physical exercise in patients with coronary artery disease as well as in age-matched controls. PloS one, 4(5), e5665. https://doi.org/10.1371/journal.pone.0005665
- Butt, M. S., & Sultan, M. T. (2011). Coffee and its consumption: benefits and risks. Critical reviews in food science and nutrition, 51(4), 363–373. https://doi.org/10.1080/10408390903586412
Related Posts
Do you have any questions about nutrition and health?
I would love to hear from you and answer them in my next post. I appreciate your input and opinion and I look forward to hearing from you soon. I also invite you to follow us on Facebook, Instagram, and Pinterest for more diet, nutrition, and health content. You can leave a comment there and connect with other health enthusiasts, share your tips and experiences, and get support and encouragement from our team and community.
I hope that this post was informative and enjoyable for you and that you are prepared to apply the insights you learned. If you found this post helpful, please share it with your friends and family who might also benefit from it. You never know who might need some guidance and support on their health journey.
– You Might Also Like –

Learn About Nutrition
Milos Pokimica is a doctor of natural medicine, clinical nutritionist, medical health and nutrition writer, and nutritional science advisor. Author of the book series Go Vegan? Review of Science, he also operates the natural health website GoVeganWay.com
Medical Disclaimer
GoVeganWay.com brings you reviews of the latest nutrition and health-related research. The information provided represents the personal opinion of the author and is not intended nor implied to be a substitute for professional medical advice, diagnosis, or treatment. The information provided is for informational purposes only and is not intended to serve as a substitute for the consultation, diagnosis, and/or medical treatment of a qualified physician or healthcare provider.NEVER DISREGARD PROFESSIONAL MEDICAL ADVICE OR DELAY SEEKING MEDICAL TREATMENT BECAUSE OF SOMETHING YOU HAVE READ ON OR ACCESSED THROUGH GoVeganWay.com
NEVER APPLY ANY LIFESTYLE CHANGES OR ANY CHANGES AT ALL AS A CONSEQUENCE OF SOMETHING YOU HAVE READ IN GoVeganWay.com BEFORE CONSULTING LICENCED MEDICAL PRACTITIONER.
In the event of a medical emergency, call a doctor or 911 immediately. GoVeganWay.com does not recommend or endorse any specific groups, organizations, tests, physicians, products, procedures, opinions, or other information that may be mentioned inside.
Editor Picks –
Milos Pokimica is a health and nutrition writer and nutritional science advisor. Author of the book series Go Vegan? Review of Science, he also operates the natural health website GoVeganWay.com
Latest Articles –
Top Health News — ScienceDaily
- The overlooked nutrition risk of Ozempic and Wegovyon February 4, 2026
Popular weight-loss drugs like Ozempic and Wegovy can dramatically curb appetite, but experts warn many users are flying blind when it comes to nutrition. New research suggests people taking these medications may not be getting enough guidance on protein, vitamins, and overall diet quality, increasing the risk of muscle loss and nutrient deficiencies.
- A 25-year study found an unexpected link between cheese and dementiaon February 4, 2026
A massive Swedish study tracking nearly 28,000 people for 25 years found an unexpected link between full-fat dairy and brain health. Among adults without a genetic risk for Alzheimer’s, eating more full-fat cheese was associated with a noticeably lower risk of developing the disease, while higher cream intake was tied to reduced dementia risk overall. The findings challenge decades of low-fat dietary advice but come with important caveats.
- MIT’s new brain tool could finally explain consciousnesson February 4, 2026
Scientists still don’t know how the brain turns physical activity into thoughts, feelings, and awareness—but a powerful new tool may help crack the mystery. Researchers at MIT are exploring transcranial focused ultrasound, a noninvasive technology that can precisely stimulate deep regions of the brain that were previously off-limits. In a new “roadmap” paper, they explain how this method could finally let scientists test cause-and-effect in consciousness research, not just observe […]
- Why heart disease risk in type 2 diabetes looks different for men and womenon February 4, 2026
Scientists are digging into why heart disease risk in type 2 diabetes differs between men and women—and sex hormones may be part of the story. In a large Johns Hopkins study, men with higher testosterone had lower heart disease risk, while rising estradiol levels were linked to higher risk. These hormone effects were not seen in women. The results point toward more personalized approaches to heart disease prevention in diabetes.
- Sound machines might be making your sleep worseon February 4, 2026
Sound machines may not be the sleep saviors many believe. Researchers found that pink noise significantly reduced REM sleep, while simple earplugs did a better job protecting deep, restorative sleep from traffic noise. When pink noise was combined with outside noise, sleep quality dropped even further. The results suggest that popular “sleep sounds” could be doing more harm than good—particularly for kids.
- This unexpected plant discovery could change how drugs are madeon February 3, 2026
Plants make chemical weapons to protect themselves, and many of these compounds have become vital to human medicine. Researchers found that one powerful plant chemical is produced using a gene that looks surprisingly bacterial. This suggests plants reuse microbial tools to invent new chemistry. The insight could help scientists discover new drugs and produce them more sustainably.
- A hidden cellular process may drive aging and diseaseon February 3, 2026
As we age, our cells don’t just wear down—they reorganize. Researchers found that cells actively remodel a key structure called the endoplasmic reticulum, reducing protein-producing regions while preserving fat-related ones. This process, driven by ER-phagy, is tied to lifespan and healthy aging. Because these changes happen early, they could help trigger later disease—or offer a chance to stop it.
PubMed, #vegan-diet –
- Diet type and the oral microbiomeon February 2, 2026
CONCLUSION: The diet-oral microbiome-systemic inflammation axis is bidirectional and clinically relevant. Understanding both direct ecological regulation and indirect metabolic effects is essential to support precision nutrition strategies aimed at maintaining oral microbial balance and systemic inflammatory risk mitigation.
- Consensus document on healthy lifestyleson January 22, 2026
Proteins are a group of macronutrients that are vital to our lives, as they perform various functions, including structural, defensive and catalytic. An intake of 1.0-1.2 g/kg/body weight per day would be sufficient to meet our needs. Carbohydrate requirements constitute 50 % of the total caloric value and should be obtained mainly in the form of complex carbohydrates. In addition, a daily intake of both soluble and insoluble fiber is necessary. Regular consumption of extra virgin olive oil […]
- Vitamin B12 and D status in long-term vegetarians: Impact of diet duration and subtypes in Beijing, Chinaon January 21, 2026
CONCLUSIONS: This study reveals a dual challenge among Beijing long-term vegetarians: vitamin B12 deficiency was strongly associated with the degree of exclusion of animal products from the diet (veganism), while vitamin D deficiency was highly prevalent and worsened with longer diet duration. The near-universal vitamin D deficiency observed in this study suggests that, in the Beijing context, the risk may extend beyond dietary choice, potentially reflecting regional environmental factors;…
- Nutritional evaluation of duty meals provided to riot police forces in Germanyon January 13, 2026
Background: The primary role of the German riot police is maintaining internal security. Due to challenging working conditions, riot police forces face an elevated risk of various diseases. During duty, forces are provided with meals. A balanced diet can reduce the risk of some of these diseases and contribute to health-promoting working conditions. Aim: First evaluation of the nutritional quality of duty meals in Germany based on German Nutrition Society recommendations (DGE). Methods: In…
- Iodineon January 1, 2006
Iodine is an essential trace nutrient for all infants that is a normal component of breastmilk. Infant requirements are estimated to be 15 mcg/kg daily in full-term infants and 30 mcg/kg daily in preterm infants.[1] Breastmilk iodine concentration correlates well with maternal urinary iodine concentration and may be a useful index of iodine sufficiency in infants under 2 years of age, but there is no clear agreement on a value that indicates iodine sufficiency, and may not correlate with […]
Random Posts –
Featured Posts –
Latest from PubMed, #plant-based diet –
- From paddy soil to dining table: biological biofortification of rice with zincby Lei Huang on February 4, 2026
One-third of paddy soils are globally deficient in zinc (Zn) and 40% of Zn loss in the procession from brown rice to polished rice, which results in the global issue of hidden hunger, e.g., the micronutrient deficiencies in the rice-based population of developing countries. In the recent decades, biofortification of cereal food crops with Zn has emerged as a promising solution. Herein, we comprehensively reviewed the entire process of Zn in paddy soil to human diet, including the regulatory…
- Molecular Characterization of Tobacco Necrosis Virus A Variants Identified in Sugarbeet Rootsby Alyssa Flobinus on February 3, 2026
Sugarbeet provides an important source of sucrose; a stable, environmentally safe, and low-cost staple in the human diet. Viral diseases arising in sugarbeet ultimately impact sugar content, which translates to financial losses for growers. To manage diseases and prevent such losses from occurring, it is essential to characterize viruses responsible for disease. Recently, our laboratory identified a tobacco necrosis virus A variant named Beta vulgaris alphanecrovirus 1 (BvANV-1) in sugarbeet…
- Nutrition in early life interacts with genetic risk to influence preadult behaviour in the Raine Studyby Lars Meinertz Byg on February 3, 2026
CONCLUSIONS: Nutrition in early life and psychiatric genetic risk may interact to determine lasting child behaviour. Contrary to our hypothesis, we find dietary benefits in individuals with lower ADHD PGS, necessitating replication. We also highlight the possibility of including genetics in early nutrition intervention trials for causal inference.
- Effect of the gut microbiota on insect reproduction: mechanisms and biotechnological prospectsby Dilawar Abbas on February 2, 2026
The insect gut microbiota functions as a multifunctional symbiotic system that plays a central role in host reproduction. Through the production of bioactive metabolites, gut microbes interact with host hormonal pathways, immune signaling, and molecular regulatory networks, thereby shaping reproductive physiology and fitness. This review summarizes recent advances in understanding how gut microbiota regulate insect reproduction. Accumulating evidence demonstrates that microbial metabolites…
- Rationale and design of a parallel randomised trial of a plant-based intensive lifestyle intervention for diabetes remission: The REmission of diabetes using a PlAnt-based weight loss InteRvention…by Brighid McKay on February 2, 2026
CONCLUSIONS: This trial will provide high-quality clinical evidence on the use of plant-based ILIs to address the epidemics of obesity and diabetes to inform public health policies and programs in Canada and beyond.
- Diet type and the oral microbiomeby Daniel Betancur on February 2, 2026
CONCLUSION: The diet-oral microbiome-systemic inflammation axis is bidirectional and clinically relevant. Understanding both direct ecological regulation and indirect metabolic effects is essential to support precision nutrition strategies aimed at maintaining oral microbial balance and systemic inflammatory risk mitigation.



















