Why Coffee Is Good and Bad For You — Yeah, Both!

Everyone’s sparing over whether coffee is good or bad.  Even the research is contradictory.  Here I present two learned views, and sprinkle on my own 2 cents. Make sure you read the UPDATEs at the bottom.

MY FANTASY is to solve this coffee debate by providing overwhelming evidence to support either that it’s good for you or bad for you.

Certainly, smart and informed people take opposite views on the topic.

(About coffee they act like economists: “You can line up all the economists in the world and never reach a conclusion!”)

Sometimes coffee analysts even contradict themselves.  Seemingly.  Because, you see, the coffee-thing is a nuanced topic.  Whether coffee’s good or bad for you depends on an assortment of things that all have to do about you.  Mostly.

Let’s start out with a few purported reasons why coffee is good and then a few reasons it’s not.


Coffee Is Good For You Because:
  1. It may reduce your risk of dying
  2. It just might reduce incidences of colon cancer
  3. It may be reduce the risk of diabetes


Coffee Is Bad For You Because:
  1. It increases stress
  2. It reduces the cells’ capacity to respond to blood sugar
  3. Unfiltered coffee leaks the most diterpenes into your body

As I’ll reproduce in a moment, the people who proffered the three “Coffee’s Good” and ‘Coffee’s Bad” items above each have several more declarations to buttress their respective points of view.

And, as mentioned, one of them also counters his own position given specific nuances associated with you – meaning, whoever’s doing the coffee drinking.

First up – because I side with his bias – is Dr. Mark Hyman of the The Blood Sugar Solution and other many good things.  The three “Bad Coffee” declarations are his.

Like me, he’s been smitten by a good cup of joe; in his case, Coffea Arabica, of which he imbibed mercilessly during his Emergency Room years.

He eventually had a conversion:

“As I began to tune into my body and provide it with what it really wanted – fresh, whole, real, unprocessed foods, sleep, relaxation, and the time to enjoy the life I had created for myself and my family – I was able to break up with coffee and make up with my health.” (Source)

In part, that conversion occurred as Dr. Hyman began to read contradictory studies about the health impacts of coffee.

Some showed that coffee drinking could help avoid diabetes, but the nuance was that this was largely for populations studied that had healthy blood sugar levels and insulin capacities to begin with.

Dr. Hyman’s #3 item above (“Coffee Bad”) underscores how squirrely this subject is.  Turns out, those diterpenes (from which steroids are derived) ain’t all bad, as they are known to be antimicrobial and anti-inflammatory.

Nonetheless, the good doctor figures the bad outweighs the good.


Dr. Hyman’s 10 Reasons Coffee Is Not Good For You

1. The caffeine in coffee increases catecholamines, your stress hormones.  The stress response elicits cortisol and increases insulin.  Insulin increases inflammation and this makes you feel lousy.

2. Habituation to caffeine decreases insulin sensitivity, making it difficult for your cells to respond appropriately to blood sugar.  High blood sugar levels lead to arterial deterioration and increased risk of mortality related to cardiovascular disease.

3. Unfiltered coffee has the highest amount of beneficial antioxidants yet also leaks the most diterpenes into your system.  These diterpenes have been linked to higher levels of triglycerides, LDL and VLDL levels.

4. The helpful chlorogenic acids which may delay glucose absorption in the intestine have also been shown to increase homocysteine levels– an indicator for increased risk of cardiovascular disease which tends to be elevated in diabesity.

5. The acidity of coffee is associated with digestive discomfort, indigestion, heart burn, GERD and dysbiosis (imbalances in your gut flora).

6. Addiction is often an issue with coffee drinkers and makes it really difficult to rely on the body’s natural source of energy.  Ask any coffee drinker about how it feels to withdraw from coffee, and you will mistake their story for that of a drug addict’s…

7. Associative addictions trend with coffee – who doesn’t immediately think of warm, frothy sweet cream and sugar when they picture coffee?  Surely the business of coffee has inspired a culture addicted to the sugary, fatty tastes of what has become more of a meal than a drink! That morning latte is the epitome of food lacking nutrition density yet packing energy!

8. 5-HIA, an organic acid and component of the neurotransmitter serotonin ( the happy chemical) seen in the urine tends to be elevated in coffee drinkers which means they may be at risk for lower levels of serotonin synthesis in the brain.  Serotonin is necessary for normal sleep, bowel function, mood, and energy levels.  It is a vicious cycle as caffeine can disrupt sleep and promote anxiety and depression. We all know someone who tends to be tired, wired and over caffeinated!

9. Elevated urinary excretion of important minerals such as calcium, magnesium and potassium have been noted in coffee drinkers. An imbalance in your electrolyte status can lead to serious systemic complications.

10. Constituents in coffee can interfere with normal drug metabolism and detoxification in the liver making it difficult to regulate the normal detoxification process in the liver.  Another issue to be aware of with coffee intake is how certain medications such as levothyroxine (thyroid) as well as tricyclic antidepressants are poorly absorbed, making symptoms curiously worse for patients.

Now, if this is convincing, stop here and go straightway to Dr. Hyman’s post, Ten Reasons to Quit Your Coffee! and read there his 13 tips on how to avoid withdrawal symptoms.

For those of you who continue to “Hear No Evil, See No Evil and Speak No Evil” because of the horrible notion of quitting the morning (and afternoon and evening) celebration of java, read on…

[Yes, Petra, I’m thinking of you.  : – )]

Because there’s hope, and it comes from my new Twitter friend @PeakT, creator of PeakTestosterone.com (which every guy over 30 and the women who love them should visit).

@PeakT is Lee Myer and Lee Myer wrestles over the coffee good/bad debate.  The three items above in “Coffee Good” is his.

In his post, Ten (Really Good) Reasons to Drink Coffee, (actually, there are really 11, all with footnoted research studies), which I shall here reproduce, Lee dives in the deep end.


Lee Myer’s 11 Good Reasons To Drink Coffee

1.   Mortality.  Coffee is one of those rare factors that can actually reduce your risk of dying.  The reason:  it is close to neutral or maybe slightly positive with regards to cancers deaths but significantly reduces cardiovascular death rates.  For example, a 2008 study followed over a 100,000 men and women for 18 years and found a clear dose dependent decrease in all cause (overall) and cardiovascular mortality. [1] Remember:  dose dependence is the gold standard of such studies and adds more weight to the evidence, because it meant that the more coffee that was consumed the less the risk of dying.  Previous studies had found the same thing by the way.  NOTE: Decaf coffee showed the same results but to a lesser degree. [1]

2.  Cancer Reduction.  The mortality studies mentioned above do not show significant overall cancer reduction among coffee drinkers.  However, coffee does appear to decrease the risk of certain specific types of cancer, including cancer of the colon, kidney and non-melanoma skin. [2]  Still other studies have shown that coffee offers signficant protection against prostate cancer, especially the most agressive kind. [3] And, interestingly enough, the same benefits were found for decaffeinated coffee, indicating the results came from coffee’s phytochemicals and not the caffeine itself.

3.  Diabetes.  Another mystery of coffee consumption is the fact that it seems to, in the short term, negatively affect glucose metabolism and insulin sensitivity yet very significantly reduces the risk of diabetes according to multiple studies. In fact, those who drank seven or more cups per day had only one half the risk. [4]

4.  Weight Loss and Weight Maintenance.  Coffee, both through caffeine and some of its consituent ingredient, has been shown to help keep those pounds off. [5]

5.  Dementia and Alzheimer’s Reduction.  Several studies have shown that coffee reduces the risk of dementia and Alzheimer’s, unlike tea. [6]  3-5 cups/day confers optimal protection according to one study.  In fairness, one study did not find such a reduction. [7]  However, the reason is likely the dose as yet another study found that too much coffee resulted in a loss in cognitive gains. [8]  Again, right around 3 cups appears to be the sweet spot.

6.  Alertness and Mental Performance.  It’s no secret that coffee boosts your mental sharpness, endurance and acuity.  The studies show alertness and mental performance are enhanced with coffee consumption. [9]  It may not turn you into Einstein, but it can give you a decided edge.  One study found a dose dependent response where the more coffee that was consumed, the better the cognitive performance. [10]  NOTE: Decaf coffee did not have nearly the same benefit.

7.  Exercise and Athletic Performance.  Coffee boosts lipolysis, the ability of your body to burn fats and rates of nerve impulse transmission. [11]  This means greater endurance and, therefore, performance in most exercise and athletic conditions. One study of middle distance runners showed that it improved overall race time, final stretch run speed and VO2. [12] What else is there, eh? By the way, coffee does this without exclusively relying on caffeine’s epeniphrine-boosting properties.  For example, one study showed that coffee actually dampened the effects of epinephrine. [13]

8.  Reduced Blood Pressure.  This one has researchers scratching their collective heads.  Some initial studies showed that coffee increased blood pressure and thus the risk of hypertension.  However, follow-up work showed clearly that heavy, “chronic” coffee drinkers actually had lower blood pressure. [14] The threshhold is about 5 cups/day and has the strongest correlation in males.

9.  Parkinson’s Disease.  A 2002 meta-analysis shows “strong epidemiological evidence that smokers and coffee drinkers have a lower risk of Parkinson’s disease”.  [15] (This is just about the only disease where smoking is protective.)  The reduction in risk for 3 cups/day is in the range of 25-30%.  A previous study from a few years prior had arrived at the same conclusion. [16]

10.  No Floride.  This is just an apologetic argument to use with your tea-drinking friends.  Green tea is similar to coffee in the sense that it is a caffeinated beverage that strongly reduces the risk of cardiovascular disease, some cancers and all cause mortality.  However, green tea has a big disadvantage:  an abundance of flouride.  Flouride can be hard on the brain and your precious neurons.  Black tea has a lot of flouride and green tea double that.

11.  Prostate Cancer.  One recent study found that heavy coffee drinkers, decaf or regular, had a 20% reduction in all kinds of prostate cancer and a 60% reduction in the most aggressive form of prostate cancer. [17]

(Go to here to read more and check out the research noted in the brackets [ ].)

Sounds pretty good, huh? Aren’t you glad you don’t have to contemplate fighting those caffeine addiction headaches anymore?

Well, before you jump up and high five everyone at Starbucks, go to Mr. Myer’s post and note his bold “CAUTION”.

Because despite these 11 “go for it”, coffee-is-good items, @PeakT knows there’s a downside.  It’s all there on the Interwebs.  He calls it: The Potential Dangers of Coffee and Caffeine.

And this returns us to a comment I made at the outset of this post:

“Whether coffee’s good or bad for you depends on an assortment of things that all have to do about you.”

You need to know your body and its propensities, such as:

-Does too much caffeine give you the jitters, or interrupt your sleep?

-Do you have high blood pressure?

-Do you feel more stressful after drinking coffee?

-Do you have an electrolyte imbalance?

In effect, you need to re-read Dr. Hyman’s list (above).

And while you’re at it, go read how Lee Myers answers a question from one of his forum subscribers who is confused about the pros and cons of java swilling.  It gets back to the nuances.  Read his answer here.


My Bottom Line On Coffee

Mine might not be yours, but my bottom line about coffee is that for most of us, less is more.  For some of us, any is too much.  And then for the very few, pour it on, my blood type is C-positive. (“C” for “caffeine”.)

It’s your responsibility to discover in which camp you light your morning fire.

You love the taste, the buzz, and the morning ceremony?!  OK, have one cup.  Then turn to green tea for the rest of the day. (And there is that stuff called “water”.)

[Read my Nine Reasons to Drink Green Tea (and limit coffee).]


UPDATE #1: Brian St. Pierre in his post on PrecisionNutrition.com may have found the most important factor to determine whether coffee is good or bad for YOU. He writes:

One reason that evidence on the health effects of coffee is so mixed is that people clear caffeine at different rates. Caffeine is broken down and cleared by the liver, and our genetic makeup shapes how quickly and effectively we can do this.

On one hand, “slow” metabolizers of caffeine don’t process caffeine effectively. These are people who are adversely affected by caffeine, get the jitters, and are wired for up to nine hours after consumption.

Others just get a boost in energy and alertness for a couple of hours; they are considered “fast” metabolizers of caffeine.

Brian knows his stuff, and he backs it up with research.  Read more of what he has to say here.

UPDATE #2: Recent studies indicate that the type of roast (dark, medium, light), how the coffee is filtered and whether milk is added — all substantially alter how coffee impacts your health. Read Why The Most Healthy Coffee Is Without Milk.

Last Updated on April 11, 2023 by Joe Garma

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Joe Garma

I help people live with more vitality and strength. I'm a big believer in sustainability, and am a bit nutty about optimizing my diet, supplements, hormones and exercise. To get exclusive Updates, tips and be on your way to a stronger, more youthful body, join my weekly Newsletter. You can also find me on LinkedIn, Twitter and Instagram.

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