Pros and Cons of Coffee and Caffeine

Posted on June 25, 2020 by Kayley O'Brien

Pros and Cons of Coffee and Caffeine

Pros	Cons
Initially Gives You Energy	Can Cause an Energy Crash When Caffeine Wears Off
Can Aid in Fat Loss	Can Inhibit Nutrient Absorption
Can Help You Have a Bowel Movement	Can Increase Anxiety
Can Reduce Pain and Cure Headaches	It Can Be Physically and Mentally Addictive
Can Make You Feel Better When Sick	Causes Withdrawals and Headaches
	Coffee Can Contain Harmful Chemicals, Pesticides, And Mycotoxins
	Can Interfere with Sleep
	Can Harm Feti (Plural of Fetus) and Infants

Pros:

1) Initially Gives You Energy

Coffee’s energizing effect is one the biggest reasons that people drink it. Coffee helps many tired people get up early, work off little sleep, and stay awake on long road trips. Caffeine is the component in coffee responsible for this boost in energy.

To understand how caffeine works in your body, you must first understand how adenosine (a chemical present in human cells) affects your body. As you go about your day, adenosine slowly accumulates in the brain, binding to adenosine receptors. This causes you to feel tired. However when you consume caffeine, the caffeine molecules bind to the adenosine receptors in place of adenosine. Although caffeine closely resembles adenosine, it does not have the same fatiguing effects. Consequently, caffeine temporarily blocks your brain from feeling tired (1).

Additionally, caffeine stimulates adrenaline and noradrenaline (your fight or flight hormones) (2). These hormones activate the sympathetic nervous system (your fight or flight response) which prepares your body for action: heart rate increases, pupils dilate, bronchi relax (increasing your lung capacity), digestion is put on pause, and you get an increase in energy.

2) Can Aid in Fat Loss

(picture from Energy Balance Nutrition Consulting)

Many studies suggest that caffeine has the potential to aid in weight loss. While studies are inconclusive, there is an association between increased caffeine (primarily coffee) consumption and decreased Calorie consumption. This is believed to be caused by an appetite suppressing effect from coffee (possibly caffeine) (3, 4, 5). However, decaf coffee also showed appetite suppressing effects (but to a lesser degree than caffeinated coffee) so the component in coffee responsible for this is unclear (6, 7, 8).

Caffeine has also been theorized to aid weight loss via increasing non-exercise activity thermogenesis (that is burning calories through non exercise related movement). Since caffeine boasts energy, it causes and increase in activity and fidgeting resulting in greater energy expenditure (you burn more calories) (3, 9).

When you combine these two mechanisms, coffee can cause you to consume less Calories and burn more Calories which can contribute to weight loss, but only if you are in a true caloric deficit (that is burning more Calories than you are consuming forcing your body to burn stored body fat for energy).

Caffeine (or coffee) is not a magic weight loss supplement, simply consuming it will unlikely have much impact on your weight. “A 12-year study on caffeine and weight gain notes that the participants who drank the most coffee were, on average, only 0.8–1.1 lbs (0.4–0.5 kg) lighter at the end of the study period” (6, 7). Another factor in this is tolerance. Over time your body builds up a tolerance to caffeine and does not get the same initial fat burning energy high (4, 10).

However, if used smart, caffeine could potentially help you lose weight. For example, a cup of coffee (black or with a little milk to keep Calories to a minimum) before a workout could help you push harder and burn more Calories. Another example is having a bulletproof coffee (coffee with butter in it) instead of breakfast. This is popular in the Keto community. A coffee with 1-2 tbsp of butter is only 100-200 Calories (a typical meal is 400-700 Calories). Due to the satiety of butter and the appetite suppressing effects of coffee, bulletproof coffee can be a low calorie satisfying breakfast.

Also, to combat caffeine tolerance, a cyclical approach involving periods of consuming caffeine and periods of abstaining from caffeine could theoretically increase the weight loss effects from coffee.

3) Can Help You Have a Bowel Movement

Many people find their morning cup of joe is quickly followed by an urge to poop. One study found nearly 1/3 of people (29%) claim coffee induces a desire to defecate soon after consumption (11, 12, 13). This study was observational and only had 99 participants so the statics are rough estimates to be taken with a grain of salt.

Never the less, several studies have shown caffeine to significantly increase contractions in your colon and intestinal muscles (11, 14, 15). The magnitude of these contractions “is similar to a meal, 60% stronger than water and 23% stronger than decaffeinated coffee” (11, 16). It is theorized that the increase in colon activity is caused by gastrin (a hormone that increases with coffee consumption) (12).

While caffeine (and coffee) appear to help some people eliminate, personal experience is the best way to know if this is true for you.

4) Can Reduce Pain and Cure Headaches

Several studies found caffeine to be an effective cure for some headaches (17, 18). A simple cup of coffee could even snuff out throbbing head pain (18).

How does this work?

Remember how caffeine binds to adenosine receptors. Well this doesn’t only boast energy, it also increases vasoconstriction in the brain. Vasoconstriction is when the blood vessels narrow (like in the picture above) decreasing blood flow to the brain and decreasing total brain blood volume. This reduces pain (17, 18).

Caffeine has also been shown to increase the effectiveness of some pain relief drugs. Low doses of caffeine are present in some antidepressant, anti-inflammatory drugs, and pain relief drugs (18, 19).

Note it’s important to understand how drugs impact each other before combining them. Some combinations are very dangerous. Make sure you know it’s safe before drinking caffeinated beverages with medicine.

Also, caffeine (and coffee) should only be used to treat headaches in moderation because as you will see in the cons section, caffeine can also cause headaches. While caffeine can offer a temporary fix, treating the root cause is the best way to cure headaches (or any sickness for that matter) (23).

5) Can Make You Feel Better When Sick

Like we just talked about, coffee and caffeine can offer pain relief and can enhance the effectiveness of some pain medications. Combine this with it’s energy boosting properties and a cup of coffee can make for an effective cold medicine.

One study found that coffee increased the alertness, reaction time, and cognitive functions of individuals with the common cold as well as decreased their general grogginess (20). “Research [also] suggests the antioxidant activity from coffee, specifically from ferulic and caffeic acids, has anti-inflammatory, antibacterial, and antiviral effects” (21, 22). Therefore coffee could actually help fight off infections.

Coffee also has drying effects which can help decrease congestion and clear up a runny nose. But beware it can also be dehydrating which is unfavorable, especially when sick. To combat this drink lots of water.

While coffee may improve your symptoms and possibly even help fight the cold, the most beneficial things for overcoming sickness are: drinking plenty of water, eating healthy food, and resting (23). Don’t drink coffee too late or it might interfere with sleep and thus recovery.

Cons:

1) Can Cause an Energy Crash When Caffeine Wears Off

Although caffeine initially gives you energy, some people experience an energy crash typically around 5 hours after they last consumed caffeine. Caffeine induced energy crashes vary from person to person and are affected by many things. Inadequate sleep the night before, consuming a large quantity of caffeine, low caffeine tolerance, infrequent consumption of caffeine, and genetics can all increase the likelihood and severity of a caffeine induced energy crash (17, 24, 25).

Remember back to the first pro, where we discussed how caffeine initially gives you energy; caffeine blocks adenosine receptors inhibiting the sleepy effects of adenosine. During a caffeine energy high, the body does not stop producing adenosine so when the effects of caffeine wear off and adenosine receptors free up, adenosine floods in and binds to the receptors which makes you tired (1, 24).

2) Can Inhibit Nutrient Absorption

Caffeine has been shown to decrease nutrient absorption. While it’s effects are minimal, this could be an issue for people with low nutrient levels or low nutrient intake (especially iron or calcium).

Calcium-

Caffeine can decrease bone density by depleting your body of calcium (a mineral essential for building and maintaining bones). Caffeine has been shown to decrease the “renal reabsorption of calcium, and possibly [reduce] intestinal calcium absorption efficiency” (26). This causes a greater percentage of the calcium consumed to get excreted in the feces before the body can absorb and utilize it.

Caffeine intake has also been shown to waste some of the absorbed nutrients by increasing “the urinary excretion of calcium, magnesium, sodium and chloride for at least 3 [hours] after consumption” (26).

While this might sound concerning, the effects are minimal. “According to studies, the negative effect of caffeine on calcium absorption is small enough to be fully offset by as little as 1–2 tablespoons of milk” (26). The main concern here is caffeine consumption paired with a diet low in calcium. If adequate calcium is consumed, then this doesn’t appear to be an issue.

Iron-

Another mineral negatively impacted by coffee is iron. Studies have shown both coffee and tea reduce iron absorption. Interestingly, the absorption of heme iron (iron we get from eating animals) was not impacted as much as non heme iron (iron we get from eating plants) (27, 28).

Researchers believe the cause of decreased absorption comes from a variety of compounds in coffee and tea. Although caffeine may partial contribute, polyphenols likely play a larger role (27).

Similar to calcium, and other nutrients inhibited by coffee, this decrease in absorption is likely not cause for concern. “Several studies show that coffee, [tea,] and caffeine are not associated with iron deficiency in healthy people with no risk of iron deficiency” (27, 29, 30, 31).

However if you have or are at risk for iron deficiency anemia, reducing or eliminating coffee and tea might be a good idea. Reducing the strength of the beverage (like shorter steeping times and lower ratio of coffee/tea to water) and consuming coffee/tea at least 1 hr away from meals could also help lessen the impacts on iron absorption (27).

People commonly at risk for iron deficiency anemia include: pregnant women, infants (especially under 6 months), children, women with heavy menstruation, people with celiacs (true gluten allergy), vegans and vegetarians (people with low to no heme iron intake), people who have had a gastrectomy (the partial or entire removal of the stomach), people taking PPI (proton pump inhibitor) medications, people with peptic ulcer disease, people with colon cancer, and people with hook worm (32).

Other Factors-

Coffee and tea are not the only things that decrease nutrient absorption; anti-nutrients in plants, eating too quickly, low bioavailability of nutrients, and excess stress also decrease nutrient absorption. While absorbing lots of nutrients is vital to health, the loss of some is inevitable and definitely not catastrophic. To reiterate, if you do not have nutrient deficiencies (especially of calcium and iron), than drinking coffee and tea is likely not an issue.

3) Can Increase Anxiety

Jitteriness and anxiety are associated with caffeine intake, especially in those who do not consume caffeine regularly. Caffeine releases cortisol (a stress hormone) (33) and excites our fight or flight response by releasing the hormones adrenaline (aka epinephrine) and noradrenaline (aka norepinephrine) (2, 34). This prepares your body for action and potential danger hence the name fight or flight (fight or run for your life).

When in this state, one is so highly energized, he can get to the point of shaking. Research also suggests that this can promote anxiety, especially in people with panic disorder and social anxiety disorder (34, 35).

Jitteriness and anxiety appear to be worse when people have more than their typical doses of caffeine. Regular coffee drinkers that stick to their typical dose, are less likely to experience these effects (34).

4) It Can Be Physically and Mentally Addictive

Caffeine is a drug and like all other drugs it is addictive.

The mechanism for this addiction is centered around a neurotransmitter called dopamine. Dopamine is responsible for motivation, happiness, feelings of reward, and is key for survival. When you engage in habits such as eating, sex, and forming friendships; dopamine is released and you feel happy. Your brain then creates a memory of the stimulant that caused the dopamine release and begins to crave it. This is called the reward pathway (36).

Drugs also stimulate dopamine and the reward pathway, but to a much higher degree. While sex and your favorite food stimulate about 92-94 ng/dL of dopamine. Drugs stimulate about 100-1,100 ng/dL of dopamine (harder drugs like meth are towards the higher end and softer drugs like caffeine and marijuana are toward the lower end) (37). This serge of dopamine causes one to crave and love their morning coffee.

In addition, when dopamine levels are high, levels of serotonin decrease. Serotonin is a neurotransmitter responsible for satiation (36, 38). When levels are low, your body feels less satisfied and wants more of the dopamine exciting substance. Hence you reach for another mug filled to the brim with delicious coffee.

Over time your body can develop a tolerance to caffeine and need more caffeine to feel the same effects. This is another common characteristic of addictive drugs.

5) Causes Withdrawals and Headaches

When you miss your daily coffee or decide to quit cold turkey; fatigue, pounding headaches, nausea, and sadness often set in. This is the dreaded caffeine withdrawal.

Quitting drugs almost always comes with withdrawals. Fortunately, caffeine is milder than most drugs and so are the withdrawals.

But why do you get withdrawals?

As stated in the section on addiction, over time your body develops a tolerance to caffeine. To combat extreme energy surges, your body creates more adenosine receptors. This allows you to still feel the tiresome effects of adenosine. In other words, your body changes in anticipation of daily coffee. It now needs this caffeine to feel normal. If you want the same energy rush as before, you would need to increase your caffeine intake. This is drug tolerance (5, 39).

When you skip your usual coffee or decide to quit, great fatigue sets in. This is because you now have lots of adenosine receptors and no caffeine to block the effects of adenosine. Therefore your receptors are flooded with adenosine and you feel more exhausted than if you had never consumed caffeine in the first place (5).

If you are quitting coffee, don’t worry in a few days or weeks your body will readjust (decreasing adenosine receptors) and you won’t need caffeine to feel like your usual self (5).

Tolerance also works with dopamine receptors. When your receptors are constantly flooded with large quantities of dopamine, your body decreases the number of receptors in order to decrease your dopamine high. This way of maintaining homeostasis leads to the feeling of needing more drugs (including caffeine) to achieve the same level of happiness and is why you feel sad when you don’t get your typical fix (36, 37).

This mechanism is far more drastic in hard drugs like cocaine, meth, and heroin; and is a main factor in their addictive nature. In softer drugs like caffeine and marijuana, this mechanism works on a mild scale; making them addictive but not as addictive as hard drugs. For this reason, when you skip your typical coffee, you don’t get the anticipated dopamine fix. Low dopamine levels combined with less dopamine receptors prevents you from feeling as happy. However, if you continue to abstain from caffeine, with time your body will increase dopamine receptors and your mood will stabilize (36, 37).

Throbbing headaches are another common symptom of withdrawal. As we saw in the section on pain reduction and headaches, caffeine is a vasoconstrictor (constricts blood vessels and decreases blood flow) in the brain. This gives caffeine the ability to cure headaches. However when a typical coffee drinker, misses their daily dose, the blood vessels of the brain dilate and blood comes rushing in. This increase in blood flow is what causes headaches in caffeine withdrawal (40, 41).

If you want to quit coffee and minimize the withdrawal symptoms, gradually coming off is your best bet. An example of this can be seen in the picture below. To minimize the effects even more add a 1/2 cup coffee phase or 1 cup of green tea phase right before fully giving up coffee.

6) Coffee Can Contain Harmful Chemicals, Pesticides, And Mycotoxins

“Coffee is one of the most chemically treated crops, with some estimates stating every acre of coffee gets treated with 250 pounds of agricultural chemicals” (42, 5).

That’s a lot of chemicals; and if they are killing off insects and pests they are likely poor for our health as well. In fact studies suggest that exposure to pesticides can increase birth defects, decrease fertility, decrease immunity, and increase risk for cancer. Although it’s important to note that the degree of toxicity varies among different pesticides and the amount ingested or exposed to (43).

Given that coffee is one of the most chemically treated crops, buying organic is especially important. The organic certification has strict regulations that prohibit the use of pesticides (44). Therefore if you drink organic coffee, pesticides are not a concern.

Another concern with coffee is mycotoxins. Mycotoxins are toxic secondary metabolites of mold. What does that mean?

When certain crops like coffee are stored and processed poorly; an optimal environment for mold growth is created. This mold flourishes and produces harmful metabolites (mycotoxins) such as Ochratoxin A (45).

Research suggests that Ochratoxin A may increase risk of cancer, decrease immunity, cause kidney damage, inhibit protein synthesis, inhibit mitochondrial respiration, inhibit ATP formation, and increase the formation of free radicals (45, 46).

Proper storing and processing procedures are often neglected in favor of more efficient and profitable large scale procedures. This focus on profit over quality leads to the development of mycotoxins such as Ochratoxin A in many coffee beans.

A study of 51 coffee samples from France, Germany, and Guatemala found that 96% of the samples contained Ochratoxin A (47). While another study of 128 coffee samples found that 56% contained Ochratoxin A (45). The small sample sizes explains the variation in numbers here; never the less they both show the prevalence of Ochratoxin A in coffee.

So what can you do?

Buy coffee from companies who engage in proper storing and processing procedures. While this can be difficult to determine, looking at coffee company websites can help. If they are adamant about proper storage, avoiding mold, and producing quality coffee; their website will likely tell you all about it.

Another option is to buy dark roast coffee. Studies show that longer roasting times and higher roasting temperatures significantly decrease Ochratoxin A levels in coffee (47, 45). Therefore dark roast coffee has less Ochratoxin A compared to light or medium roast.

In case you were wondering; chemicals, pesticides, and mycotoxins are just as much of an issue in decaf coffee as they are in regular caffeinated coffee. In fact chemicals used in the process of removing caffeine may also be harmful (42, 47, 48).

One last note on chemicals in coffee: what you make your coffee in is important. A stainless steal or glass French press or a ceramic dripper (using unbleached filters) is a much better alternative compared to plastic coffee machines, plastic French presses, plastic drippers, and bleached filters. Repeatedly using hot water in plastic could lead to chemical components from plastic leaching into your coffee (42).

To recap, buying organic, dark roast, properly processed coffee and making it without the use of plastic or bleached filters is the best way to avoid consuming chemicals, pesticides, and mycotoxins along with your morning coffee.

7) Can Interfere with Sleep

While an energy boost from caffeine can be great during the day, one can curse it’s lingering effects when it’s time for bed and he can’t stop tossing and turning.

Studies suggest that caffeine consumption 6 or less hours before bed increases the amount of time it takes to fall a sleep and decreases total sleeping time (49, 50, 51).

This can be a problem as sleep debt accumulates. In some cases, insufficient sleep leads to increased caffeine consumption to offset fatigue. Unfortunately this makes falling asleep even more difficult creating a vicious cycle.

Can you still enjoy coffee without it negatively impacting your sleep?

While everyone is different, the answer is likely yes. You can avoid caffeine induced sleep issues by abstaining from caffeine 4-11 hours before bed and by sticking to a moderate dose of caffeine (1-3 cups of coffee) (49, 50). Individuals metabolize caffeine at different rates so how late one can get away with consuming caffeine varies greatly, hence the 4-11 hours recommendation. The best way to know where you fall is to experiment.

8) Can Harm Feti (Plural of Fetus) and Infants

It is generally advised that pregnant and nursing women consume no more than 200 mg of caffeine per day (35, 52, 53). An 8 oz cup of coffee typically has 70–140 mg of caffeine (with an average of 95 mg) so pregnant and nursing women should have no more than 11– 22 oz of coffee a day (54). Note if consuming caffeine from other sources like chocolate, soda, or tea; decrease your coffee intake further to avoid exceeding 200 mg a day.

Limiting or eliminating caffeine while pregnant is important because caffeine can cross the placenta and enter the baby’s bloodstream, potentially causing harm to the baby (52, 55).

Caffeine is eliminated slower in feti and babies under 6 months “because neither the placenta nor the fetus itself has cytochrome P450, the enzyme that metabolizes caffeine” (35). As a result, caffeine has a half life 8.3 to 16 hours longer in feti, than it does in adults. Half life is a common scientific measurement of how long it takes a substance to reduce to half of it’s initial concentration. This longer half-life means that the effects of caffeine will last longer in the fetus (35).

Research suggests that the more caffeine consumed during pregnancy, the greater the chance of a miscarriage (35, 52). A study of 130, 456 pregnant women “reported that, compared to a no or very low caffeine intake reference group (0–50 mg/day during pregnancy), every additional 100 mg/day of caffeine (about the amount contained in a typical [8 oz] cup of coffee) increased the risk of pregnancy loss (both miscarriage and stillbirth) by 7%” (56, 35).

Caffeine has also been shown to decrease birth weight (52, 35, 55). A meta-analysis of 10 studies found that for every 100 mg of caffeine (about 1 8 oz cup of coffee) consumed per day by pregnant mothers, the risk of low birth weight (less than 5.5 lbs) for their babies increased 3%. This meta-analysis also found a 37.8% increase in risk of low birth weight among pregnant mothers with the highest intake of caffeine (55). Birthweight is a common measure of infant health. Low birthweight increases infant risk for developmental difficulties, health complications, and premature deaths (57).

Breast feeding mothers are also advised to keep their caffeine intake below 200 mg a day to ensure the health of their babies (55). As stated earlier, babies under 6 months can not fully metabolize caffeine and therefore caffeine stays in their system much longer (35). Caffeine can also increase fussiness and impair sleep in infants (35).

Caffeine has also been shown to decrease iron concentrations in breast milk (35). This is a concern for babies under 6 months who are already predisposed to risk of iron deficiency anemia (35, 32). Caffeine can also dehydrate the mother causing her to produce less milk which means less food for her baby.

In general the less caffeine pregnant and nursing women have, the greater the chances of having a healthy baby. While limiting consumption to 200 mg or less will likely have little effects on the health of the baby, the less caffeine you consume during pregnancy and nursing the better.

So Should I or Should I Not Consume Coffee?

Now that you know the pros and cons of coffee and how it effects your body, lets look at people who might benefit from coffee and people who are better off avoiding it.

People Who Might Benefit From Drinking Coffee	People Who Might Benefit From Avoiding or Limiting Coffee
People Who Want to Lose Weight and Use Caffeine to Increase Energy for Work Outs and For Appetite Suppression	People with Vitamin Deficiencies (Especially Iron and Calcium)
People Who are Constipated	People with Osteoporosis
People With a Long Road Trip Ahead	Pregnant and Nursing Women
Tired People With Important Deadlines	People with Insomnia
People Who Feel Good When They Consume It	People Who Don’t Feel Good When They Consume It
People with Headaches (For Immediate Relief)	People with Headaches (Regular Coffee Consumption Can Cause Headaches)
People Who Are Sick	People with Anxiety

Lets Look at How This Could Play Out In Real Life:

Example 1:

Kate has anxiety, osteopenia (the precursor to osteoporosis), and heavy menstrual bleeding (making her at risk for iron deficiency anemia). She is very alert in the morning but still drinks coffee because she likes the taste. After drinking coffee her hands get very shaky and her anxiety worsens.

Kate is a great example of someone who could benefit from cutting out caffeine. This could improve her anxiety, osteopenia, and iron levels (reducing her risk of iron deficiency anemia). Decaf coffee or tea could replace her morning coffee so she still gets a tasty warm beverage.

Example 2:

Tom carries an extra 50 lbs of body weight and is looking to lose fat. Due to family obligations and work, 6 am is the best time for him to workout. Yet he struggles to drag himself out of bed and to the gym at that hour. Tom wants to be more productive and energetic in the morning. An occasional coffee always leaves him feeling great. He gets a little energy boast, is more active and motivated, and never gets shaky or anxious.

Tom is a great example of someone who could benefit from introducing caffeine. A cup of coffee in the morning could give Tom the energy he needs to crush his workout and have a productive morning. Coffee also has appetite suppressing effects which could help Tom stick to eating in a Caloric deficit (eating less calories than you burn causing your body to tap into fat stores for energy). Both increasing his activity and eating less would help Tom lose weight.

Concluding Thoughts:

Everybody has unique nutritional needs based on their lifestyle and genetics. Now that you have learned how coffee and caffeine effect the body, you are one step closer to making an informed decision on how much caffeine is right for you. All that’s left to do is a little experimenting.

P.S. If you like the taste of coffee but want a caffeine free option, check out my chicory and dandelion root coffee. It is a delicious tea that tastes similar to, but not exactly like, coffee.

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(Some of these sources require subscriptions to view the whole study. I get access through my school. If you go to or have gone to college, you can likely gain free access through your school’s library database.)

Category: Health Articles

Pros and Cons of Coffee and Caffeine