Legend has it that coffee was discovered around 850 A.D. in Ethiopia by a goat herder who observed that their animals were unusually lively after eating bright-red berries. Inside those berries were the coffee beans that later went on a global journey. Now, with more than 400 billion cups consumed every year, coffee is the world’s most popular beverage. 

There has been a lot of research on the health benefits of coffee such as improved attention, focus, energy, motivation and neuroprotective effects.

But like all things – it is best to consume in moderation as drinking coffee or to much coffee might not be the best thing for you. Just like coffee has a ton of health benefits it also has some side effects that can be problematic for some people. You may want to make a self assessment to see if your coffee drinking could be impacting your health issues. Let’s have a look at some of the issues with drinking coffee or too much of it.

1. Increased Blood Pressure and Heart Rate 

Caffeine is a central nervous system stimulant, so high or even regular consumption of caffeine may create anxiety, restlessness, irritability, insomnia. In fact, caffeine-induced anxiety disorder is one of four caffeine-related syndromes listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is published by the American Psychiatric Association.

Extremely high daily intakes of 1,000 mg or more per day have been reported to cause nervousness, jitteriness and similar symptoms in most people, whereas even a moderate intake may lead to similar effects in caffeine-sensitive individuals.

Studies have found that higher caffeine intake appears to increase the amount of time it takes to fall asleep. It may also decrease total sleeping time. Coffee contains theophylline, which is known to disturb normal sleep patterns. Caffeine intake even six hours before bedtime has been shown to significantly disrupt sleep. (1)

2. Increased Blood Pressure and Heart Rate

Regular consumption of caffeine may create cardiac sensitivity – abnormal heart beats, tachycardia and palpitations, increased blood pressure and hypertension, especially in those that have atherosclerosis and heart disease. Although moderate coffee consumption is generally considered safe for heart health, acute ingestion can lead to short-term increases in blood pressure and heart rate, particularly in non-habitual drinkers or those with hypertension. (2)

3. Potential for Dependence and Withdrawal

Caffeine dependence is well-documented. Withdrawal symptoms—such as headaches, fatigue, irritability and even constipation —can occur in regular consumers who abruptly stop intake. Skipping or giving up coffee a person can expect to potentially feel worse before feeling better. (3)

4. Gastrointestinal Distress: 

Coffee contains chlorogenic acid and N-alkanoyl-5-hydroxytryptamide, which have been shown to increase stomach acid production. Increase in gastric acid secretion may exacerbate symptoms of acid reflux or gastroesophageal reflux disease (GERD). (4). A study found that coffee beans that were roasted longer and at higher temperatures were less acidic, which means darker roasts tend to be less acidic than lighter roasts and switching to cold-brewed coffee is less acidic than hot coffee.

5. Bone Health Concerns

High coffee consumption has been associated with decreased bone mineral density in some studies, potentially increasing the risk of fractures in susceptible populations, especially in those with low calcium intake. (5) One study found a higher rate of bone loss in postmenopausal elderly women with caffeine intakes >300 mg/d than in those with intakes ≤300 mg/d. (6,7)

6. Loss of Nutrients

While coffee itself contains small amounts of essential nutrients like magnesium, potassium, and niacin, its effect on the absorption or excretion of other nutrients is of more concern. It can increase the excretion of the minerals calcium, magnesium, potassium, sodium, phosphate and zinc; and vitamins including B vitamins – particularly thiamin, and vitamin C. It may also reduce absorption of iron and calcium (especially when caffeine is consumed around mealtimes).

Coffee, especially when consumed with or shortly after meals, inhibits the absorption of non-heme iron (from plant sources), primarily due to its polyphenol content. (8) Some studies have suggested increased urinary excretion of magnesium and zinc with high caffeine intake, although evidence is less consistent. (9)

7. Caffeine Addiction

Studies suggest that although caffeine triggers certain brain chemicals similarly to the way cocaine and amphetamines do, it does not cause classic addiction the way these drugs do. (14) However, it may lead to psychological or physical dependency, especially at high dosages.

Even though caffeine does not seem to cause true addiction, if a person regularly drinks a lot of coffee or other caffeinated beverages, there’s a very good chance they may become dependent on its effects and as such when they miss there morning cup of joe those withdrawal symptoms (as mentioned earlier) kicks in.

8. Increased Urination 

Increased urination is a common side effect of high caffeine intake due to the compound’s stimulatory effects on the bladder. Some people may notice that they need to urinate frequently when they drink more coffee or tea than usual.

As a chemical, caffeine increases production of urine, which means caffeine is a diuretic. But the Mayo clinic reports that most research suggests that the fluid (which is made up of more than 95% water) in caffeinated drinks balances the diuretic effect of typical caffeine level. So its diuretic effects are often too low to dehydrate you on its own. High doses of caffeine taken all at once may increase the amount of urine the body makes. This is more likely if you aren’t used to caffeine.

How Much Coffee Should I Drink?

The Food and Drug Administration (FDA) has stated that healthy adults should only consume about 3 to 5 cups (up to 400 milligrams) daily to avoid potentially dangerous or adverse side effects. It is also best to consume coffee away from food to avoid interference with digestion and nutrient absorption.

For special populations such as pregnant individuals: ≤200 mg/day is advised to reduce risk of miscarriage and low birth weight. (10)

Several individual factors influence how caffeine is processed, and thus what is considered a “safe” or tolerable dose such as genetics, (people with the liver enzyme CYP1A2 responsible for metabolizing caffeine are more susceptible to caffeine’s negative cardiovascular effects, such as hypertension or heart attack risk) (11); Age (older adults metabolize caffeine more slowly due to reduced liver enzyme activity); Sex (women metabolize caffeine more quickly when taking oral contraceptives or during pregnancy due to hormonal influences on liver enzymes) (12); Smoking increases caffeine clearance by up to 50% and Medications, including certain antibiotics and antidepressants, can either increase or reduce caffeine metabolism. (13)

Conclusion

Coffee is a complex beverage with both health-promoting and also potentially detrimental side effects. The key lies in moderation—generally considered to be 3–5 cups per day for most healthy adults or up to 400mg of caffeine. Individual tolerance, underlying medical conditions, and lifestyle factors may determine if coffee should be reduced or eliminated. To get the benefits of caffeine without undesirable effects, consider conducting an honest assessment of your sleep, energy levels, headaches, digestion and other factors that might be impacted by caffeine, and reduce your intake if needed.

References

1. Drake, C., et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine, 9(11), 1195–1200. https://doi.org/10.5664/jcsm.3170
2. Mesas, A. E., et al. (2011). The effect of coffee on blood pressure and cardiovascular disease in hypertensive individuals: a systematic review and meta-analysis. American Journal of Clinical Nutrition, 94(4), 1113–1126. https://doi.org/10.3945/ajcn.111.016667
3. Juliano, L. M., & Griffiths, R. R. (2004). A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology, 176(1), 1–29. https://doi.org/10.1007/s00213-004-2000-x
4. Zhang, M., et al. (2013). Dietary habits and the risk of gastroesophageal reflux disease: a comparative study. Scandinavian Journal of Gastroenterology, 48(9), 936–941. https://doi.org/10.3109/00365521.2013.816130
5. Hallström, H., et al. (2006). Long-term coffee consumption in relation to fracture risk and bone mineral density in women. American Journal of Epidemiology, 165(8), 901–908. https://doi.org/10.1093/aje/kwk058
6. Rapuri, Prema B. et al. 2001. “Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes,” Am J Clin Nutr (November). http://ajcn.nutrition.org/content/74/5/694.full (accessed May 29, 2015)
7. Heaney, R. P. (2002). Effects of caffeine on bone and the calcium economy. Food and Chemical Toxicology, 40(9), 1263–1270. https://doi.org/10.1016/S0278-6915(02)00094-7
8. Morck, T. A., Lynch, S. R., & Cook, J. D. (1983). Inhibition of food iron absorption by coffee. American Journal of Clinical Nutrition, 37(3), 416–420. https://doi.org/10.1093/ajcn/37.3.416
9. Nehlig, A. (2016). Effects of coffee/caffeine on brain health and disease: What should I tell my patients? Practical Neurology, 16(2), 89–95. https://doi.org/10.1136/practneurol-2015-001162
10. American College of Obstetricians and Gynecologists (ACOG). (2010). Moderate caffeine consumption during pregnancy. Committee Opinion No. 462. https://www.acog.org/
11. Cornelis, M. C., et al. (2006). Coffee, CYP1A2 genotype, and risk of myocardial infarction. JAMA, 295(10), 1135–1141. https://doi.org/10.1001/jama.295.10.1135
12. Abernethy, D. R., & Todd, E. L. (1985). Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. European Journal of Clinical Pharmacology, 28(4), 425–428. https://doi.org/10.1007/BF00606601
13. Berthou, F., et al. (1992). Effect of smoking on caffeine metabolism. Clinical Pharmacology & Therapeutics, 52(5), 476–480. https://doi.org/10.1038/clpt.1992.181
14. https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2017.00200/full

Coffee is a delicious drink consumed by people of all different cultures and from all around the world. Coffee contains hundreds of bioactive compounds that contribute to its potentially powerful health benefits. Caffeine is a naturally occurring substance in coffee as well as tea, and chocolate – and is artificially added to energy drinks. Once consumed, caffeine is absorbed into the bloodstream and travels to the brain. Although the health benefits of coffee are mainly based on caffeine, coffee also contains many bioactive compounds and antioxidants such as chlorogenic acid, caffeic acid, kahweol, cafestol, and trigonelline.

How Does Caffeine Work on our Brain?

Adenosine is a neurotransmitter in your brain that promotes sleep. Neurons in your brain have specific receptors that adenosine can attach to. When it binds to those receptors, it inhibits the tendency of neurons to fire. This slows neural activity.

Adenosine normally builds up during the day and eventually makes you drowsy when it’s time to go to sleep. Caffeine and adenosine have a similar molecular structure. So when caffeine is present in the brain, it competes with adenosine to bind to the same receptors. Caffeine doesn’t slow the firing of your neurons like adenosine does. Instead, it prevents the adenosine from slowing down neural activity.

How Does Caffeine Boost Brain Function

Caffeine can lead to an increase in resting brain entropy. Brain entropy is vital to brain function, and high levels point to high processing abilities. An increase in resting brain entropy suggests higher information-processing capacity (1). 

Caffeine also stimulates the CNS by promoting the release of other neurotransmitters, including noradrenaline, dopamine, and serotonin (2). This helps to boost mood and motivation, and help us to be productive during the day. 

Caffeine and Cognitive Function

Coffee and caffeine may also affect your memory, but the research on this is mixed and more studies are needed. Some studies suggest that caffeine may have a significant positive effect on both short-term and long-term memory (3,4). Caffeine also appeared to make memories more resistant to being forgotten, compared with the placebo group.

Caffeine may improve various aspects of brain function, including reaction time, vigilance, attention, learning and general mental function. (5)

That said, you may develop a tolerance to caffeine over time. This means you will need to consume more coffee than before to get the same effects.

Keep in mind, however, that more isn’t always better. One study looked at abstainers, low consumers (one cup or equivalent a day), moderate (one to five cups a day), and high (five or more cups a day). The moderate and high consumers were found to have higher levels of anxiety and depression than the abstainers, and the high consumers had the greatest incidence of stress-related medical problems, as well as lower academic performance. (6).

Caffeine and Neuroprotective Effects

Research suggests that regular coffee drinkers (1–4 cups per day) may be associated with a reduced risk of neurodegenerative disorders, including Parkinson’s and Alzheimer’s diseases. The caffeine and polyphenols in coffee may exert protective effects on the brain by reducing oxidative stress and inflammation. (7)

Reduced Mortality Risk

A large prospective study found that coffee drinkers had a lower risk of death from various causes, including cardiovascular disease, neurological disorders, and suicide. (8)

Brain Injury and Caffeine

Despite the potential benefits of caffeine in managing concussion symptoms, it is essential to note that there are currently no studies directly examining the effects of caffeine consumption on concussions in humans. 

While much of the existing research highlights caffeine’s properties, such as its neuroprotective and anti-inflammatory effects, these findings predominantly come from studies on animal models or general neurological conditions rather than concussions. Consequently, there remains a significant gap in understanding how caffeine might influence concussion recovery in humans.

Many people recovering from a concussion or brain injury will often want to use caffeine to help combat there cognitive fatigue or “brain fog”. However, the research is divided on whether or not caffeine is harmful after a brain injury. Caffeine in small amounts may be safe after a TBI, but excessive caffeine consumption could slow down the recovery process. Caffeine is a vasoconstrictor, which means it constricts the blood vessels in the brain, reducing blood flow. Without enough cerebral blood flow, the brain cannot get the vital nutrients it needs to repair itself.

On the one hand, coffee contains antioxidants that help the brain reduce inflammation and function more efficiently and help to provide neuroprotection and support mood, energy levels and focus. On the other hand, some studies show that caffeine blocks the release of adenosine, a neuroprotective agent that brings down inflammation and promotes brain healing. As a result, it could potentially slow down the recovery process. (9)

The injured brain needs a good amount of sleep to aid the healing process. It’s difficult to get that sleep in the period immediately following your injury. The recommended Brain Rest Protocol  calls for 7 to 8 hours of sleep every night. A person’s pre-injury caffeine habit can disrupt that schedule. Limiting caffeine intake may help a healing brain get the much-needed good night of sleep.

Caffeine can exacerbate some of the brain injury related symptoms such as headaches and can stimulate an already overstimulated brain but as identified above it can also help combat some of the cognitive, energy and mood issues that are associated with brain injury as well.

How Much Coffee Should I drink if I have a Brain injury or a Concussion?

This will vary from person to person based on age, sex, genetics, medications, health issues and smoking. 

The Food and Drug Administration (FDA) has stated that healthy adults should only consume about 4 or 5 cups (400 milligrams) daily to avoid potentially harmful or adverse side effects. However, for individuals with a concussion or brain injury it is suggested to be a lot lower.

Medical Director and founder of Mid-Atlantic Concussion (MAC) Alliance, Vincent Schaller, MD, DABFM, CIC. recommends no more than 100 mg., which is equivalent to 8-oz. cup of black coffee. He did note however that as headaches decrease and sleep improves, the amount of caffeine intake can be gradually increased. 

Summary:

Caffeine has been well researched and shows a lot of health benefits including neurological health benefits. Research has shown that it can help improve mood, motivation, attention, energy, focus, reaction time, learning, memory and can be neuroprotective against Alzheimer’s and Parkinsons disease. Caffeine consumption and tolerance will vary from person to person and although it can be great for someone that has sustained a concussion or TBI it should be consumed responsibly and in the first stages following a concussion or TBI coffee intake should be limited to only 1 cup a day (100mg of caffeine). 

To find out more about the negative effects of caffeine please check out this article. 

References:

1. https://www.nature.com/articles/s41598-018-21008-6
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC7132598/
3. https://pubmed.ncbi.nlm.nih.gov/15678363/
4. https://pubmed.ncbi.nlm.nih.gov/11713623/
5. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-3010.2007.00665.x
6. https://pubmed.ncbi.nlm.nih.gov/1410146/
7. Eskelinen, M. H., & Kivipelto, M. (2010). Caffeine as a protective factor in dementia and Alzheimer’s disease. Journal of Alzheimer’s Disease, 20(s1), S167–S174. https://doi.org/10.3233/JAD-2010-091527
8. Freedman, N. D., et al. (2012). Association of coffee drinking with total and cause-specific mortality. New England Journal of Medicine, 366(20), 1891–1904. https://doi.org/10.1056/NEJMoa1112010
9. https://pubmed.ncbi.nlm.nih.gov/12943586/