Dr. Maia Love MD, FRCPC, RYT, IHEMFunctional Medicine, Nutrition



Good for you, or bad for you, or somewhere in between?

Briefly, research studies show that coffee reduces inflammation, stabilizes blood sugar, and protects the lining of blood vessels; however, this is in unhealthy people. The studies that show benefit are those done in people with diabetes or heart disease. In healthy people, coffee can be detrimental, or benign, or advantageous. I hope I have your attention now. In some people, coffee increases something called “CRP”, a marker of inflammation, that is also increased in some autoimmune diseases.

So the coffee dilemma.

To truly understand something, I like to investigate the origins, to go deep, to understand from as many angles as possible.

Coffee is brewed from the roasted seeds of the Coffea plant. The Coffea plant is native to tropical Africa. An “understory” bush, that grows under a higher level canopy of forest trees, the Coffea plant blooms small white flowers that turn into bright red berries. The berries are then picked, roasted and brewed with hot water in a process called infusion to draw out the caffeine. The caffeine in the Coffea plant protects the plant from insects and prevents other plant seeds from being able to grow, as proven through studies of adding caffeine to soil.



Photo credit: Maia Love


Studies on caffeine and insects once led researchers to consider the use of coffee as an insecticide. Coffee disrupts the growth of insects and can trigger paralysis and death in some. After ingesting coffee, insects lose the ability to have organized behaviour, with spider’s webs becoming distorted; frogs and snails die from slowed heart rates and birds and mammals suffer damage to the liver, kidneys and brain and even death. However, horses show improved performance and less physical and mental fatigue when fed coffee, such that use of coffee with horses is banned for horse racing. Bees prefer lemon and grapefruit flowers, and remember them better, with both of these kind of flowers containing caffeine naturally.




Caffeine is a bitter, white, crystalline purine; a “methylxanthine alkaloid”. It is related to components of DNA and RNA – our gene molecules. The caffeine molecule is similar to the molecule adenosine. Adenosine causes relaxation and drowsiness, and keeps the nervous system from getting super hyped up. The caffeine molecule blocks adenosine receptors thus blocking the effects of adenosine thus causing alertness. Caffeine is found in cacao, chocolate, tea and some artificial products like soft drinks and prescription drugs

Caffeine also increases adrenaline; an activating molecule. Adrenaline can increase performance and is part of the sympathetic nervous system. The sympathetic nervous system is part of the fight or flight response and part of hypervigilance. If activation of the nervous system causes stress, then cortisol is increased which can lead to hormonal imbalance if the body chooses making cortisol over making hormones like progesterone and testosterone. Progesterone and testosterone at lower than normal levels can impact health significantly. In addition, activation of the fight or flight response can cause irrational decisions as the brain chooses the faster decision over taking the time to think through the decision. Of note, in the short term after drinking coffee, heart rate and blood pressure increase and rapid shallow breathing increases which then deprives the brain of oxygen. However, this is a short-lasting response.

Coffee was originally brought to humans, as far as our records show, by the Sufi’s in Arabia. Coffee was used to keep people up to be part of the Arabic Sufi rituals. Ahmad al-Ghaffar writes of coffee in the 15th Century, which is the first known written document. After discovery, coffee use spread widely by the 16th Century to the Middle East and Northern Africa, then Italy, then Europe, then finally, the Americas.

When taken, the effects of coffee enter the body through the stomach and small intestine and take effect within 15 minutes. Effects can last for at least 6 hours, the half life of coffee or caffeine. A half life is the amount of time for half of a substance to be reduced by the body. So the total effects can last for up to 24 hours. For example, if you have coffee at 8 am, you still have 25% of that coffee in your system at 8 pm. Caffeine causes a physical dependence, with signs of withdrawal being headaches, fatigue, muscle pain, and irritable mood.

So what are the good things versus bad things about coffee for humans?

Should you have that cup of coffee tomorrow morning?


Benefits of Coffee

  • Increased alertness
  • Improved performance: however, research shows the improved performance is short-term and only occurs in those that are addicted to coffee as it counteracts the decrease in attention due to withdrawal from coffee. In those without an addiction to coffee, the coffee did not have a benefit on performance (1).
  • Reduced cancer risk: 2 cups of coffee per day was associated with less risk of oral, pharynx, liver, colon, prostate, endometrial, and melanoma risk; however, it was associated with increased lung cancer risk (2,3).
  • If you have type two diabetes and are a woman, then coffee reduces inflammation (4).
  • Lower risk of kidney stones (5).


Costs of Coffee

  • Insomnia: studies show that caffeine reduces the amount of deep sleep. In deep sleep, astrocytes restore the brain by removing waste products from the brain and depositing them in the blood for removal by the liver. If coffee is consumed after noon, deep sleep is interrupted. (10)
  • Mood: studies show that people drinking coffee can become more irritable and anxious. Caffeine reduces REM sleep which is where emotional stability is recharged (11).
  • Control: due to reduced sleep, regular caffeine drinkers are more likely to be impulsive and have difficulty with self control.
  • Creativity and problem solving: coffee inhibits the brains ability to access the “default modal brain network”. This network is the one that allows us to daydream, to relax, to sit back. When we regularly access this part of our brain, we improve our problem solving and creativity. In addition, by inhibiting REM sleep, caffeine inhibits creative thinking (12).
  • Handling stress: coffee reduces the ability to handle stress, in association with decreased sleep quality.
  • Increased inflammation: a small study showed that, in athletes that took coffee versus those that did not, oxidative stress and IL-6 expression, increased which are markers of inflammation. Adrenaline, lactate, and glucose also increased in the caffeine group. However, IL-10 also increased which reduces inflammation. Although the study says that inflammation was decreased, the presence of IL-6 in the blood, rather than the muscle, indicates an increase of inflammation (13). CRP, a marker of inflammation, was reduced when healthy women drank decaffeinated coffee, compared to regular coffee (4).
  • Decreased minerals: we required minerals as helpers for our enzymes to work properly and our soil is now deplete of minerals thus our food has less mineral content than it used to. Caffeine increases excretion of minerals, with studies showing reduced calcium, magnesium, potassium, and zinc in coffee drinkers.


Remains Unclear

  • Death: coffee has been associated with more risk of death but when those who also smoked cigarettes were excluded, then coffee drinking had an “inverse” association with death – this means that there was less death from heart and lung disease, injuries, accidents, diabetes and infections when people drank coffee. However, people with heart disease, cancer, and stroke were excluded in the NIH study. So, it still doesn’t seem quite clear (14).
  • Inflammation in healthy women: no change to CRP and inflammation in healthy women in one study and, decreased CRP and blood vessel inflammation when drinking decaffeinated coffee in healthy women (4).


Your Decision

Personally, I love having coffee every once in a while. Especially on rainy Vancouver mornings with a full day of work ahead of me. Or a gorgeous Americano Misto on a Sunday morning with friends. My friends enjoy coffee, the energy it gives them to work out and the appetite reducing effect to support less caloric intake and a slim physique. However, I have also experienced times when coffee seems to make my edge too sharp and my thinking less measured, so I see it as a sometimes enjoyment, rather than something to use daily. I have observed how it affects my performance, mood, attention, energy, stomach and overall feeling of well-being and have made a decision accordingly.

So, what will you do?

Consider doing a self study.  Choose a week where you have coffee daily and a week where you don’t have it daily.

Notice how you feel on the parameters of: (1) depth of sleep, (2) focus and concentration, (3) mood such as contentment, enjoyment, irritability, sharpness, (4) exercise performance, (5) energy levels – do you get a “crash” after 4 hours of drinking coffee that you don’t get if not drinking coffee? Or are you too drowsy if you don’t drink coffee and so feel unable to not have it in your life, (6) consider, if you have an inflammatory condition, conducting the experiment with measurements of CRP levels when regularly drinking coffee and two weeks after not drinking coffee, (7) notice how you handle stress on coffee versus off coffee, (8) note self control, and (9) perhaps monitor disease parameters with your doctor on coffee versus off coffee. It may be that certain genetics or illnesses respond better to coffee, and certain ones do not.

So see what suits you. Evolve your personalized wellness plan with this in mind. For more information, also consider reading Chris Kresser’s review on coffee (15).

Wishing you the best in your caffeine decisions,

Dr. Maia Love





Literature references:

1. Cappelletti et al, 2015, in: Curr Neuropharmacol. “Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug?” from the School of Medicine and Psychology, Italy.

2. Wang et al., 2016, in: Scientific Reports. “Coffee and cancer risk: A meta-analysis of

prospective observational studies.” from Beijing, China.

3. Kennedy et al., 2017, in: BMJ. “Coffee, including caffeinated and decaffeinated coffee, and the risk of hepatocellular carcinoma: a systematic review and dose–response meta-analysis.” from the Universities of Southampton and Edinburgh.

4. Lopez-Garcia et al., 2006, in: Am J Clin Nutr. “Coffee consumption and markers of inflammation and endothelial dysfunction in healthy and diabetic women.”, from Harvard.

5. Ferrero et al., 2014, in: Am J Clin Nutr. “Caffeine intake and risk of kidney stones.” Dec; 100(6): 1596–1603, from the Department of Medical Sciences, Italy.

10. Clark and Landholt, 2017 in: Sleep Med Review. “Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials.” from the University of Zurich, Switzerland.

11. Travis Bradbury, 2012, in: Forbes. “Caffeine: The Silent Killer of Success.” Travis is the Authour of Emotional Intelligence 2.0 and co-founder of TalentSmart, with a degree in psychology from the University of California, San Diego.

12. Maria Konnikova, 2013, in: The New Yorker. “How caffeine can cramp creativity.”

13. Tauler et al., 2013, in: Med Sci Sports Exercise. “Effects of caffeine on the inflammatory response induced by a 15-km run competition.”, from the Research Institute of Health Sciences, Spain.

14. Freedman et al., 2012, in NEJM. “Association of Coffee Drinking with Total and Cause- Specific Mortality”, from the NIH, Washington, DC.

15. Kresser, blog post. “Coffee is good for you – unless it’s not!” at https://chriskresser.com/coffee-is-good-for-you-unless-its-not/

16. Asprey, blog post. “The Science behind just one mold toxin in your coffee.” at https://blog.bulletproof.com/one-ugly-mug-the-science-behind-just-one-mold-toxin-in-your-coffee/


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