Caffeine and the Brain: Part 2

Caffeine and the Brain: Part 2

Did you miss Caffeine and the Brain: Part 1? Read it HERE.

In Caffeine and the Brain: Part 1, we looked at how caffeine has become a universal habit and why it can be detrimental to achieving maximal health. We discussed the egregious consumption of a pesticide and stimulant, but how exactly does caffeine work, scientifically, once it gets inside our brain? It acts as a central nervous system stimulant,1 by binding to adenosine receptor sites, blocking adenosine from doing its job.2

Adenosine is an inhibitory neurotransmitter, which normally helps the body relax.3 This explains why caffeine causes sleep issues4 and alertness when sleep-deprived.5 Caffeine molecules are stopping adenosine from doing its job.6

However, your body is smart, and is a big believer in a thing called “homeostasis,” meaning it likes to keep things the same.7 So when you start drinking large amounts of caffeine8 your body makes more of these adenosine receptor sites, and you need more caffeine to block them, since you feel caffeine’s effects via blocking a large majority of these receptors.9, 10

Caffeine is a vasoconstrictor, narrowing blood vessels, and decreases blood flow, and sometimes used in pain relief medications.11 By blocking adenosine from doing its job, caffeine also increases respiratory rate.12 However, caffeine ingestion promotes neurotransmitter release (acetylcholine, monoamines, etc.) which is how it does its job, as a stimulant.13 Meanwhile, dopamine and glutamate are released in the nucleus accumbens (your brain’s pleasure center).14

When following a Paleo Diet and lifestyle, look to the scientific basis behind leaving caffeine out. It’s better to rely on your body’s own natural energy stores. Natural sleep and wake cycles are ideal, and help your body function optimally.15 This isn’t possible when you are drinking lots of caffeine.16

And, as most of you already likely know, caffeine also causes cortisol to be released.17 Your body thinks some kind of emergency is happening, and it wants to prepare you. Humans need extremely huge doses of caffeine in order for it to become toxic.18 However, other animals are not nearly as tolerant (hence its original use as a pesticide).19 Below is the effect seen on a spider, that has ingested caffeine.20

Interestingly, caffeine is legal and unregulated, which is not at all the case for basically every other psychoactive drug in the world.21 In fact, Dr. William Dement, professor from Stanford University, posits if caffeine were introduced today, it would not be made legal.22 The addictive nature and withdrawal effects are well-documented23 among the sleep, stimulant, and biochemical effects.24

Noever, R., J. Cronise, and R. A. Relwani. 1995. Using spider-web patterns to determine toxicity. NASA Tech Briefs 19(4):82. Published in New Scientist magazine, 29 April 1995.

Noever, R., J. Cronise, and R. A. Relwani. 1995. Using spider-web patterns to determine toxicity. NASA Tech Briefs 19(4):82. Published in New Scientist magazine, 29 April 1995.


Thorn Caroline F, Aklillu Eleni, McDonagh Ellen M, Klein Teri E, Altman Russ B. “PharmGKB summary: caffeine pathway” Pharmacogenetics and genomics (2012).


Genetically, caffeine has a stronger effect on some individuals, compared to others.25 Humans with at least one C variant of CYP1A2, a gene, react less favorably to caffeine, and metabolize it slower.26 This could possibly explain the difference between you, and your friend who goes off the rails on just one cup of espresso.

Besides this scientific evidence, caffeine depletes magnesium stores, causing many effects downstream.27 These effects can be exhibited as: poor sleep, muscle cramps and chronic pain.28 About 50% of people in the United States are deficient in magnesium, whether due to too much caffeine, or not enough magnesium consumption to begin with, though it’s likely both.29

Caffeine, if consumed, is best kept at the ‘therapeutic’ dose, of 100-200mg per day.30 Incorporating caffeine into your Paleo Diet isn’t advisable, however, if you’re looking to maximize its effects. If looking to minimize your pesticide load, organic coffee is more ideal, and green tea offers L-theanine, which has a calming effect on the brain, along with lower amounts of caffeine, compared with coffee.31, 32

Lastly, let us not forget that the most beneficial beverage of all…water! A Paleo Diet should be hydrating, and keep your cells happy! Raise your glass (or bottle) to good health!


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15. Krystal AD. How the circadian rhythm affects sleep, wakefulness, and overall health: background for understanding shift work disorder. J Clin Psychiatry. 2012;73(2):e05.

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24. Smith JE, Lawrence AD, Diukova A, Wise RG, Rogers PJ. Storm in a coffee cup: caffeine modifies brain activation to social signals of threat. Soc Cogn Affect Neurosci. 2012;7(7):831-40.

25. Cornelis MC, Byrne EM, Esko T, et al. Genome-wide meta-analysis identifies six novel loci associated with habitual coffee consumption. Mol Psychiatry. 2014;

26. Available at: // Accessed October 15, 2014.

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32. Chacko SM, Thambi PT, Kuttan R, Nishigaki I. Beneficial effects of green tea: a literature review. Chin Med. 2010;5:13.

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“2” Comments



  3. how about drinking Yerba Mate ? It also contains coffeine, but instead of flushing magnesium, yerba mate gives this macroelement and many others such as Potassium, Iron, Vitamins.

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