What are the good and bad health effects of coffee?

I'll comment on coffee and the heart.

I've written about this in detail in the following link Benefits of Coffee : Getting To The Heart Of The Matter.

The following facts are worth highlighting. Coffee is often associated with the development of high blood pressure however studies have shown that in those that regularly drink coffee there is no association with high blood pressure, even in those drinking up to 6 cups a day. Several studies have found an association between coffee drinking and decreased incidence of diabetes. Moderate coffee consumption may be associated with a small decrease in the risk of stroke, although the studies examining that are by no means definitive. Well designed studies have demonstrated that coffee consumption is not associated with the development of arrhythmias. Several studies demonstrate a link between moderate coffee consumption and decreased risk of coronary heart disease. Well designed studies that followed participants for at least several years and recorded coffee habits demonstrate that regular coffee consumption was associated with a lower risk of developing heart disease, and a lower risk of dying from heart disease.

No study is perfect, and results of studies should always be interpreted with a degree of caution, but reassuringly, numerous well-designed studies have shown that coffee confers no significant risk of heart disease, and that in fact it may even be protective. Most of these studies looked at coffee drunk in moderation (2-4 cups) and it would appear reasonable to recommend moderate coffee consumption as part of a healthy lifestyle.

Other than caffeine, what psychoactive compounds exist in coffee and tea?

Theanine and to lesser amounts theobromine (the same psychoactive that's in chocolate) and theophylline.

Theobromine and theophylline both are methylated xanthines and are structurally very similar to caffeine (methyl groups are just positioned differently), sharing the same mild stimulating effect.

Theanine reduces stress and improves mood and cognition, but is not related to the aforementioned.

Side note: Caffeine is metabolized by the liver into paraxanthine, theobromine and theophylline

What are some good ways to stay awake without tea or coffee?

A cup of tea (white, green, oolong, black, pu-erh) is a good source of sustained energy. I find the caffeine is less spikey/jittery than coffee and longer lasting.

Also, experiment w/Yerba Mate.

How does a shot of espresso compare to a cup of coffee in terms of caffeine?

According to the respected espresso coffee industry leader illy coffee http://www.illy.com/wps/wcm/conn…

  • The average cup of espresso has 78mg of caffeine

According to the United Kingdom's Food Standards Agency – http://www.food.gov.uk/science/s…

  • The average cup of instant coffee has 75mg of caffeine
  • The average cup of brewed, percolated and drip coffee has 100mg

All the analysis I have read constantly identifies brewed, percolated and drip coffee as having more caffeine than espresso coffee (up to 125mg) and that's comparing it with a 30ml espresso extraction which I think is 5ml more than ideal.

Some research believes that it is the length of time that the hot water comes in contact with the ground coffee that produces the extra caffeine content. In espresso it is about 20-25 seconds while it is much longer in the brewed, percolated and drip coffee methods.

Interestingly the better quality beans (Arabica) have about half the caffeine content of the cheaper ones (Robusta). So, I reckon that a 25ml shot of espresso made on 100% Arabica beans is a good option for reducing your caffeine intake while still enjoying that 'elixir of the gods'.

What is the most effective way to get rid of caffeine withdrawal symptoms?

Caffeine is the most effective way to get rid of the withdrawal symptoms, probably not the answer you were hoping for and I know it is a bit obvious but the fact is if you're going to go cold turkey from a physically addictive drug you will get withdrawal symptoms.

Since about the age of 9 I've suffered from headaches all the time. After the severe lack of interest from doctors I decided to see if any changes to my diet would make a difference and I eliminated any substances that might in any way trigger them for whatever reason.

Part of this elimination process was the 5-6 cans of diet coke and about 2-3 cups of coffee a day. It didn't occur to me that I was addicted to caffeine.

After a day of elimination I developed a very intense headache. I took ibuprofen and a medication called co-proxamol (prescribed by my doctor). This made absolutely no difference at all. After 3 days I couldn't take it any more and I had guessed the association between the headache and the caffeine withdrawal and I poured myself an egg cup amount of diet coke. Within half an hour the headache completely cleared up.

Over the years, I have slowly reduced the amount of caffeine I have and I believe that is the way you need to do it. Since I've reduced the amount, I can go days without coffee and without a headache. Obviously I wouldn't want to go days but I could if I wanted to, promise.

Additional reading:

How much caffeine is in a single and double ristretto?

Hi there, a single ristretto is a single shot of espresso ( but brewed with less water), and double's just two shots.

According to the Mayo clinic, 30ml of espresso has 47-75 mg of caffeine.


What's in the volume of a shot?

  • 10g of coffee produces about 18-30 ml of espresso (probably about 18-20ml if ristretto)
  • Hence I would say that a single ristretto shot (around 20ml) could estimably have around 33mg of caffeine, while a double shot (40ml) would have about 66mg.

Are there reasons why you shouldn't drink tea or coffee close to bedtime, aside from the fact that caffeine may keep you from falling asleep?

It’s a good question and prompted me to do some research.

The disruption of sleep patterns in general has an overall negative impact on one’s health. While caffeine can delay or disrupt falling into REM sleep, over a period of time it can also contribute to the more problematic malady of insomnia. Insomnia is broadly defined as a sleep disorder that is characterized by difficulty falling and/or staying asleep.

It’s important to remember that caffeine is a stimulant. Not only is it found in tea and coffee, but also colas and chocolate, and is another common cause of insomnia. Dr Paula Franklin, assistant medical director at BUPA, states:

“Insomnia is common in people whose daily intake exceeds 600mg of caffeine a day – and each tea or coffee contains 80-150mg.” 

Sleep experts suggest that you should stop drinking caffeinated beverages at least 8 hours before bed.

One also has to caution making too many broad claims about the effects caffeine on sleep. Body chemistry and individual metabolism dictates our level of sensitivity to caffeine. Caffeine sensitivity depends on your metabolism in relation to the combination of how much, and how often you consume coffee or tea. Being highly sensitive to caffeine may not only contribute to insomnia but also contribute to additional side effects. Adding increased nervousness and gastrointestinal upset to the list will also have a negative impact on enjoying a sound sleep.

Conventional wisdom also posits that caffeine has diuretic properties, which contributes to fluid loss. Having to urinate also disrupts your sleeping patterns. Again, consistently disrupted sleep patterns is unhealthy.
Regardless of when you choose to enjoy coffee or tea, there’s a bigger question to answer: what are caffeine’s effects both positive and negative in general? Maybe it’s really just best keeping moderation in mind.

Daily Mail “Ten reasons why you're not getting a good night's sleep”
WebMD: Sleep disorders
WebMD: Caffeine Myths and Facts

Per Wickstrom
Founder of Best Drug Rehabilitation
Best Drug Rehabilitation

Can drinking too much coffee actually make you more tired?

Remember that caffeine is a stimulant.  That means that you're giving your system a boost.  But the energy has to come from somewhere.  You're just borrowing it from the future, and if there's nothing left to borrow, or nothing left later, … boom.

How does caffeine affect mental performance?

Why does caffeine affect cognitive performance?

Caffeine increases circulating epinepherine levels[a][1]. This stimulates lipolysis[b][2].

Lipolysis "involves the hydrolysis of triglycerides into free fatty acids followed by further degradation into acetyl units by beta oxidation"[3]. This produces ketone bodies, which can be burned for energy by the brain.

According to Dr. Emily Deans[4], "it is actually less efficient to make ATP from glucose than it is to make ATP from ketone bodies!" In fact, "ketosis actually increases the ATP/ADP ratio in the brain"[5].

Because ketones can be burned in most regions of the brain, more energy is available to the brain when ketone levels are elevated[4][5][6].

TL;DR: Regular consumption of caffeine can cause ketosis, and the brain is metabolically more efficient in ketosis.

What are the effects of caffeine on cognitive performance, and to what extent do these effects manifest themselves?

Caffeine appears to improve working memory as tested by performance on n-back tasks[11].

Caffeine appears to improve cognitive performance and mood, and increase thirst, as tested by "a long duration simple reaction time task and a rapid visual information processing task, and a mood questionnaire" completed once before and three times after caffeine administration. "Regular caffeine consumers appear to show substantial tolerance to the thirst-increasing but not to the performance and mood effects of caffeine"[12].

A study using U.S. Navy SEAL trainees as subjects who underwent "72 h of sleep deprivation and continuous exposure  to  other  stressors" found that "moderate  doses  of caffeine can improve cognitive function, including vigilance, learning, memory, and mood state"[13].

A study using "well-trained cyclists" as subjects found that caffeine "in a performance bar can significantly improve endurance performance and complex cognitive ability during and after exercise." "Cognitive function measures" included "computerized Stroop and Rapid Visual Information Processing tests"[14].

And from [10]: "clonidine reduced alertness, impaired many aspects of performance and slowed saccadic eye movements; caffeine removed many of these impairments."

Problems with other answers:

A problem I have with the study[7] referenced in Naomi P Saphra's answer  is that alertness was essentially self-rated using MAPSS (Mood, Alertness, and Physical Sensations Scales), which is described in [8].

MAPSS is a set of items that ask how one feels with respect to some criterion. For example, an item included on the alertness scale is as follows: "I feel mentally alert / attentive / able to concentrate / observant"; it looks like the study presented one of these (e.g., "I feel mentally alert") for each item to each subject, and had the subject rank how he/she felt (e.g., how "mentally alert" he/she felt) on a 9 point scale (ranging from "not at all" to "extremely").

The study concludes that "no net benefit for alertness is gained, as caffeine abstinence reduces alertness and consumption merely returns it to baseline." Such a conclusion cannot be reached using only data collected about how alert the subjects said they felt.

Citations and footnotes:

[1]: http://en.wikipedia.org/wiki/Caf…
[2]: http://en.wikipedia.org/wiki/Epi…
[3]: http://en.wikipedia.org/wiki/Lip…
[4]: http://www.psychologytoday.com/b…
[5]: http://josepharcita.blogspot.com…
[6]: http://www.ketotic.org/2011/02/b…
[7]: http://www.nature.com/npp/journa…
[8]: http://www.nature.com/npp/journa…
[9]: http://hyper.ahajournals.org/con…
[10]: http://jop.sagepub.com/content/1…
[11]: http://csjarchive.cogsci.rpi.edu…
[12]: http://www.ncbi.nlm.nih.gov/pubm…
[13]: http://jtoomim.org/brain-trainin…
[14]: http://www.ncbi.nlm.nih.gov/pubm…
[15]: http://www.wellesley.edu/Chemist…

[a]: This happens because caffeine is a nonselective antagonist of adenosine receptors, acting as a competetive inhibitor[1] (caffeine binds to adenosine receptors without activating them, in place of adenosine, which would activate them), and "endogenous adenosine receptors inhibit epinephrine release from the adrenal medulla and suppress plasma norepinephrine levels"[c][9] (so activated adeosine receptors contribute to lower levels of epinepherine). Circulating epinepherine levels therefore increase when caffeine prevents adenosine receptors from being activated. [15] is relevant.

[b]: Increased epinepherine levels also stimulate glycolysis, but increased availability of free fatty acids can decrease glycogen utilization[1].

[c]: Interestingly, [10] suggests that "the beneficial effects of caffeine seen in low alertness states" may be attributed to caffeine counteracting "reductions in the turnover of central noradrenaline."

How does a chocolate bar compare to a cup of coffee in terms of the amount of caffeine?

Chocolate contains little to no caffeine as far as we know. 

According to www.xocoatl.org, this is a rumor based on confusion between the similarity of two alkaloids – theobromine, which is the main chemical in chocolate, and caffeine. According to this website, quoting from The Biochemist, a scientific journal:

There is no scientific substantiation that Chocolate contains caffeine, and a great deal of evidence that it does not. The Biochemist, (Apr/May 1993, p 15) did chemical composition tests where they specifically distinguished between Caffeine and Theobromine. They found regularly up to 1.3% by weight Theobromine in Chocolate. They also found other pharmacologically active compounds including up to 2.20% Phenylethylamine up to 1.54% Tele- methylhistamine and occasionally up to 5.82% Serotonin. They could not detect any Caffeine at all.

According to the International Cocoa Organization (http://www.icco.org/faq3.aspx?id…), which measured the chemical content of coca beans after fermentation and drying, the nib is no more than 0.7% caffeine and up to 1.3% theobromine.

The Wikipedia article on chocolate, although not necessarily authoritative, mentions only theobromine and phenethylamine as the alkaloids in chocolate.  There is no mention of caffeine in the article: http://en.wikipedia.org/wiki/Cho…. 

While it's still possible that there is a significant amount of caffeine in chocolate, evidence suggests there is very little.  Therefore a cup of coffee probably has way more caffeine than a chocolate bar.