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I question the 'low - none' evaluation, caffeine has clearly been consumed, and continues to be, at a rate that proves moderate - high levels of addiction. Especially in regards to young adults and 'energy drinks'. Mw110088 ( talk) 08:56, 24 May 2017 (UTC)

Can you provide reliable medical sources that contradict the multiple sources which are used in the article which support the classification of the addiction liability of caffeine as "low/none"? Just because someone routinely consumes drinks with caffeine in them, that doesn't mean someone is addicted. Deli nk ( talk) 09:47, 24 May 2017 (UTC)

Also keep in mind the distinction between addiction and dependence. Sizeofint ( talk) 16:25, 24 May 2017 (UTC)

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Please change ".[6] Nicotine decreases the half-life by 30–50%". In the reference it is stated that smoking decreases the halflife of nicotine, most likely it is the pyrolysis products from smoking that induces the enzymes that metabolises the caffeine not the nicotine itself. So it should be changed to " Smoking decreases the halflife by 30-50%". 109.238.129.170 ( talk) 17:48, 3 June 2017 (UTC)

Not done: please provide reliable sources that support the change you want to be made. –  Train2104 ( t •  c) 17:35, 6 June 2017 (UTC)

The reference states that it is smoking and not specifically nicotine. The cited reference is support for the requested change. The addition of nicotine is a bit of original research. JSR ( talk) 17:58, 6 June 2017 (UTC)

The below content from the article is from a master's thesis. It likely does not meet WP:MEDRS or even WP:SCIRS for that matter. Sizeofint ( talk) 15:10, 7 June 2017 (UTC)

=====Effect of genetics on withdrawal symptoms=====

Gene polymorphism could be associated with caffeine withdrawal symptoms and beta-1 and beta-2 play roles in caffeine withdrawal. ^[1] For example, compared to people with homozygous Gly16 allele, people with the heterozygote ADR beta-2 Gly16 Arg gene polymorphism have a higher chance of feeling fatigue after 48 hours of caffeine withdrawal. ^[1] It has been suspected that beta2- adrenoceptors are the main cause for this increase in mental fatigue symptoms. ^[1] Beta 2- adrenoceptors are receptors that regulate glycogenolysis, secret insulin and intramuscularly transport glucose that is used for cerebral and muscle activity. ^[1]

Another example is given by the genes ADRbeta1 Gly16 Arg and CYP1A2-163A>C polymorphisms. ^[1] They are associated with peoples' mood swings and increased depression level. ^[1] Among subjects homozygous for the CYP1A2 allele, ADRbeta1 Gly389 allele carriers are reported to have a higher percentage of depression level increase when compared to Arg389 homozygotes subjects. ^[1] Adrenergic receptors, again, play a key role in this symptom, as altered norepinephrine (an adrenoceptor agonist) neurotransmission contribute to the etiology of depression. ^[1] This symptom is often seen in faster caffeine metabolizers, because caffeine effects diminish quicker in these people and provide them less opportunity to adapt to caffeine loss. ^[1]

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please change in the article on caffeine Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia and helps to protect them against predator insects and to prevent germination of nearby seeds. The most well known source of caffeine is the coffee bean, a misnomer for the seed of Coffea plants. Beverages containing caffeine are ingested to relieve or prevent drowsiness and to improve performance. To make these drinks, caffeine is extracted by steeping the plant product in water, a process called infusion. Caffeine-containing drinks, such as coffee, tea, and cola, are very popular; in 2005, 90% of North American adults consumed caffeine daily. ^[1]

to Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia and helps to protect them against predator insects and to prevent germination of nearby seeds. Caffeine is stored in the plant material in two places. Firstly, in the cell vacuoles where is t is complexed with polyphenols. This caffeine probably is released into the mouthparts of insects, to dscourage herbivory. Secondly, around the vascular bundles, where it probably inhibits pathogenic fungi from entering and colonising the vascular bundles. ^[2]

The most well known source of caffeine is the coffee bean, a misnomer for the seed of Coffea plants. Beverages containing caffeine are ingested to relieve or prevent drowsiness and to improve performance. To make these drinks, caffeine is extracted by steeping the plant product in water, a process called infusion. Caffeine-containing drinks, such as coffee, tea, and cola, are very popular; in 2005, 90% of North American adults consumed caffeine daily. ^[1] Zapostol ( talk) 14:25, 19 June 2017 (UTC)

That is probably too much detail for the lead, but I think it is worth adding to the body. Sizeofint ( talk) 17:58, 19 June 2017 (UTC)

 Done Added to the natural occurrence section. Sizeofint ( talk) 18:13, 19 June 2017 (UTC)

Aepli, A., Kurth, S., Tesler, N., Jenni, O. G., & Huber, R. (2015). Caffeine consuming children and adolescents show altered sleep behavior and deep sleep. Brain sciences, 5(4), 441-455.

Baer, R. A. (1987). Effects of caffeine on classroom behavior, sustained attention, and a memory task in preschool children. Journal Of Applied Behavior Analysis, 20(3), 225-234. doi:10.1901/jaba.1987.20-225

James, J. E., Kristjansson, A. L., & Sigfusdottir, I. D. (2011). Adolescent substance use, sleep, and academic achievement: Evidence of harm due to caffeine. Journal of Adolescence, 34, 665–673.

James, J. E., Kristjansson, A. L., & Sigfusdottir, I. D. (2015). A gender-specific analysis of adolescent dietary caffeine, alcohol consumption, anger, and violent behavior. Substance Use & Misuse, 50(2), 257-267. doi:10.3109/10826084.2014.977394

Jin, M. J., Yoon, C. H., Ko, H. J., Kim, H. M., Kim, A., Moon, H. N., & Jung, S. P. (2016). The relationship of caffeine intake with depression, anxiety, stress, and sleep in Korean adolescents. Korean journal of family medicine, 37(2), 111-116.

Kristjansson, A. L., Sigfusdottir, I. D., Frost, S. S., & James, J. E. (2013). Adolescent caffeine consumption and self-reported violence and conduct disorder. Journal Of Youth And Adolescence, 42(7), 1053-1062. doi:10.1007/s10964-013-9917-5

Richards, G., & Smith, A. (2015). Caffeine consumption and self-assessed stress, anxiety, and depression in secondary school children. Journal of psychopharmacology, 29(12), 1236-1247.

Temple, J. L., Ziegler, A. M., Graczyk, A. M., & Crandall, A. (2017). Effects of acute and chronic caffeine on risk-taking behavior in children and adolescents. Journal Of Psychopharmacology, 31(5), 561-568. doi:10.1177/0269881117691568

Mnlim ( talk) 04:41, 29 July 2017 (UTC)

Relevant new content is welcome :)! Just keep in mind WP:RS and WP:MEDRS. Unless you're up for adding this content yourself, it may take a while for someone to integrate it. Sizeofint ( talk) 05:31, 29 July 2017 (UTC)

Hi all, I will no longer be moving forward with adding these sources to the page. How can I go about removing this post? Thank you! Mnlim ( talk) 01:26, 9 August 2017 (UTC)

There really is no need to. This post will be archived in several months and it is possible another editor will find these sources useful. Sizeofint ( talk) 16:22, 9 August 2017 (UTC)

"It is weakly basic (pKa = ~0.6)" should read "It is weakly basic (pKa of conjugate base = ~0.6)". The footnote makes clear that that was the intended meaning. — Preceding unsigned comment added by 73.189.240.68 ( talk) 15:33, 5 August 2017 (UTC)

 Done Sizeofint ( talk) 16:29, 9 August 2017 (UTC)

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Remove the part which states 'Smoking tobacco increases caffeine clearance by 56%' The source makes no mention of that figure (56%) and does not directly say that tobacco smoke increases caffeine clearance. 109.255.138.123 ( talk) 16:44, 22 August 2017 (UTC)

It is there, see table 1. Sizeofint ( talk) 18:22, 22 August 2017 (UTC)

I can't see it as I don't want to pay 50 euro to download it. It's a bit silly to reference things on wikipedia without the average person being able to see the cited reference. However, I'll take your word. 109.255.138.123 ( talk) 10:24, 23 August 2017 (UTC)

It is reproduced here http://www.recoveryonpurpose.com/upload/Drug%20Interactions%20With%20Smoking.pdf Sizeofint ( talk) 16:13, 23 August 2017 (UTC)

• Addiction - some degree of aversion may actually occur, which? (with?) people preferring placebo

 Fixed Sizeofint ( talk) 06:11, 14 February 2017 (UTC)

• Effects of genetics - and beta-1 and beta-2 play roles - beta-1 & beta-2 should be fully identified here (rather than in a following sentence).
• people with the heterozygote? (heterozygous?) ADR beta-2
• Beta 2- (is it beta-2, beta2, or beta 2? - be consistent) adrenoceptors are receptors that regulate glycogenolysis, secret? insulin (insulin secretion,?) and intramusculatly transport? (intramuscular transport of? - I doubt the receptor transports insulin or glucose itself) glucose
• Arg389 homozygotes? (homozygous?) subjects
• altered norepinephrine (an adrenoceptor agonist) neurotransmission contribute? (contributes?) to
• Biosynthesis - The text describes chemical synthesis, not biosynthesis.

 Fixed It describes both I think, but I have changed the title. Sizeofint ( talk) 18:40, 6 June 2017 (UTC)

• Figure - lab synthesis - where does the nitroso (NO) group come from?

See http://www.umich.edu/~chemh215/CHEM216/HonorsCup/HC%20230-III.pdf. I think that the originator of the graphic forgot a step. JSR ( talk) 18:57, 6 June 2017 (UTC)

• Analogs - have also been elucidated? (identified?).
• Products - and inhalation? (inhalants?).
• Caffeine content in select food and drugs - 12 fl. oz. Coca-Cola Classic is listed as 34 mg and 96 mg/L but the same size Guarana Antarctica is given as 30 mg (less) and 100 mg/L (more - inconsistent).

69.72.92.65 ( talk) 06:36, 6 February 2017 (UTC)

I've added some bullets to ease parsing. Hope you don't mind. Sizeofint ( talk) 07:11, 6 February 2017 (UTC)

     I had started each item on a separate line but the returns were mysteriously deleted when I saved the page. Any idea why and how to prevent this?
          
69.72.92.92 (
talk) 07:57, 11 February 2017 (UTC)

Wiki markup is often a bit mysterious. For instance, if you insert one or more spaces at the beginning of a new line, standard Wikipedia formatting will be absent from resulting text. (You inserted six spaces above, and look what happened.) To answer your specific question: see Help:Wiki_markup#Line_breaks. Rivertorch ^FIRE _WATER 07:15, 12 February 2017 (UTC)

Unarchived, some day I'll get around to this. Sizeofint ( talk) 08:37, 25 October 2017 (UTC)

"Commercial supplies of caffeine are not usually manufactured synthetically because the chemical it is readily available as a byproduct of decaffeination." should read "Commercial supplies of caffeine are not usually manufactured synthetically because the chemical is readily available as a byproduct of decaffeination." 205.145.107.53 ( talk) 22:50, 16 November 2017 (UTC)

 Done Shellwood ( talk) 22:56, 16 November 2017 (UTC)

I've bracketted out the claim that long term consumption causes chronic arterial stiffness - because the attatched citation: Mahmud, Feely J., does not say this - least not in the abstract. It only says stiffness increases acutely. Feel free to delete the bracketed material completlely or challenge me if you do see this supported in another part of the citation. Best email me as I dont come here often. Trev M   ~  22:51, 23 November 2017 (UTC)

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The second sentence under "Adverse Effects" > "Reinforcement Disorders" > "Dependence and Withdrawal" reads:

"The frequency at which [mild to clinically significant distress or impairment in daily functioning] occurs is self reported at 11%, but in lab tests only half of the people who report withdrawal actually experience it, casting doubt on many claims of dependence."

This statement is unclear (how does a lab test distinguish between the "report" and "experience" of withdrawal?), appears patently false (94.5% of people experience no withdrawal symptoms from caffeine?) and, most importantly, is not attested in either of the sources. User:Deptstoremook ( talk) 05:23, 21 March 2018 (UTC)

@ Deptstoremook: If you bothered reading the source, you would have seen the quotation that is drawn from. "Of these caffeine consumers, 11% reported withdrawal symptoms upon cessation of caffeine ingestion. In order to empirically determine the extent of caffeine dependence, this study was carried further and 57 caffeine consumers were asked to participate in an experiment. Participants were randomly assigned to the following conditions, abrupt caffeine withdrawal, gradual withdrawal, and a caffeine maintenance control group. Thirty-eight percent of the abrupt withdrawal group was considered caffeine withdrawn. None of the other participants reported significant symptoms. In addition, an important finding from this study was that less than half of the subjects who reported experiencing severe withdrawal symptoms during the telephone interview also experienced them during the experimental phase of the study. This finding calls into question the accuracy of self-report for caffeine dependence symptoms, in particular when they are not being acutely experienced." ^[1] The quotation is from a secondary source(review), published in a high quality journal(Neuroscience & Biobehavioral Reviews), with a high impact factor(9.44). If you are still confused about how people can report experiencing something, but not actually experience it in a controlled setting, see nocebo, and placebo. Petergstrom ( talk) 06:09, 21 March 2018 (UTC)

@ Petergstrom: You are being rude. This is always uncalled for, but it's especially disheartening because your interpretation of the source is incorrect in multiple ways.

First, the article doesn't invoke the placebo or nocebo effect, but merely indicates that self-reporting may not be accurate without venturing a causal explanation.

Second, you incorrectly elide several unrelated subgroups in order to reach the statement "only half" of "11%". "Of these caffeine consumers, 11% reported withdrawal." A separate group of "57 caffeine consumers" were assigned to groups including "abrupt caffeine withdrawal." Of the abrupt withdrawal group, "Thirty-eight percent [...] was considered caffeine withdrawn." Finally, and not in explicit reference to any of the preceding groups, "less than half of the subjects" had inconsistent interview and experiment reports.

Obviously this section of the source article is not particularly well-written (despite its publication in a "high quality journal"), but that simply shifts the burden of care to us. User:Deptstoremook ( talk) 19:49, 21 March 2018 (UTC)

I was trying to be helpful by pointing you towards concepts that might have helped you understand, but whatever. The "less than half" number is in reference to the thirty-eight percent, and that is pretty clear in the text. Petergstrom ( talk) 03:32, 22 March 2018 (UTC)

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• Evergreen Life. "Caffeine consumption and metabolism test". Evergreen Life.

• Evergreen Life. "The Effects of Caffeine – How Much is Too Much?". Evergreen Life. Catherineseow ( talk) 09:07, 29 March 2018 (UTC)

 Not done Wikipedia is not the place to promote commercial products. –  Joe ( talk) 11:22, 29 March 2018 (UTC)

At the University of Toronto, Professor Ahmed El-Sohemy (nutritional scientist) has published that 10 percent of the population are homozygous for a CYP1A2 alelle that leaves caffeine lingering in the body after caffeine consumption, and they are at a markedly higher risk of heart attacks. For the same unlucky 10 percent, caffeine does not confer an advantage in athletic performance. He published this in the journal Medicine & Science in Sport & Exercise in March 2018. Can we please keep an eye on this research when and if it is replicated, included in a review, textbook or other Wikipedia-acceptable source such as an official medical recommendation. And then cite the reliable source. Thanks. 81.131.173.14 ( talk) 10:04, 12 April 2018 (UTC)

Caffeine is NOT used to treat asthma or treat depression / prevent suicide. Thus moved these Doc James ( talk · contribs · email) 07:17, 6 May 2018 (UTC)

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ORIGINAL: "It is found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia and helps..."

PROPOSAL: "It is found in the seeds, nuts, or leaves of a number of plants native to Africa, East Asia and South America and helps..."

As caffeine is named after coffee, a huge group of plants native to Africa and also the commercially and culturally most important beverage along with tea, shouldn't the prevalence of caffeine in Africa be stressed out in the introductory article? In my POV the Africa is much more associated with caffeine than South America, so it should definitely be included. — Preceding unsigned comment added by Uzifix ( talk • contribs) 15:59, 17 June 2018 (UTC)

 Done Sam Sailor 18:17, 17 June 2018 (UTC)

Summary of improvement suggestion: Would it be useful to cite and mention more specifics on US FDA regulation, more specifically, how it relates to 'cola-type beverages', which are arguably a common source of caffeine in people's diets?

Reasoning: Paragraph four in the lead section mentions the US regulatory status of caffeine the paragraph goes on to discuss specific dosages and how it relates to application in food (coffee) and safety:

Caffeine is classified by the US Food and Drug Administration as "generally recognized as safe" (GRAS). Toxic doses, over 10 grams per day for an adult, are much higher than typical doses of under 500 milligrams per day. A cup of coffee contains 80–175 mg of caffeine, depending on what "bean" (seed) is used and how it is prepared (e.g., drip, percolation, or espresso). Thus it requires roughly 50–100 ordinary cups of coffee to reach a lethal dose. However, pure powdered caffeine, which is available as a dietary supplement, can be lethal in tablespoon-sized amounts.

The FDA's GRAS substance page for caffeine in the Code of Federal Regulations (21CFR182.1180) ^[1] states the following:
(a) Product. Caffeine.
(b) Tolerance. 0.02 percent.
(c) Limitations, restrictions, or explanation. This substance is generally recognized as safe when used in cola-type beverages in accordance with good manufacturing practice.

This translates to a regulatory limit of roughly 72 mg of caffeine per 12 fl oz (355 mL) serving of cola beverage.

Chaseme ( talk) 19:38, 24 June 2018 (UTC)

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Under the "Reinforcement disorders" subject and "Addiction" sub-title, there is the phrase "whether or not", which is redundant. I just wanted to remove the "or not" part.

Thanks. Weoa ( talk) 12:21, 26 August 2018 (UTC)

 Done Thank you, - FlightTime ( open channel) 12:29, 26 August 2018 (UTC)

paragraph 3: "It may confer a modest protective effect against some diseases,[15] including Parkinson's disease.[16]" Both studies examine coffee and health benefits, not caffeine and health benefits. This wiki entry purports to be about caffeine, not coffee. — Preceding unsigned comment added by 124.121.198.215 ( talk) 11:48, 28 December 2018 (UTC)

Adverse Effects > Physical > "Doses of caffeine equivalent to the amount normally found in standard servings of tea, coffee and carbonated soft drinks appear to have no diuretic action.[68]" Note also and again the distinction between studies examining caffeine-containing beverages and the topic at hand: i.e. caffeine.

The study generalizes its results and the statement is misleading and potentially dangerous: in fact, there are individuals for whom caffeine-containing beverages cause diuresis, even in relatively small doses of caffeine. — Preceding unsigned comment added by 124.121.198.215 ( talk) 11:59, 28 December 2018 (UTC)

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I found a citation for this statement: "Toxic doses, over 10 grams per day for an adult, are much higher than the typical dose of under 500 milligrams per day." ^[1]

Found on this MedScape article.

Abstract (requires Medline membership): http://reference.medscape.com/medline/abstract/20492310 Liambdonegan01 ( talk) 23:19, 3 January 2019 (UTC)

I have added the reference to the article. Thanks for the suggestion. -- Ed ( Edgar181) 23:49, 3 January 2019 (UTC)

According to 2018 research, caffeine-activated ryanodine receptors contribute to synaptic long-term depression (LTD), which counters formation of long-term memories at precisely the key element of the long-term memory storage circuit - the hippocampus. ^[1]

• Should be added to Adverse Effects - Psychological. Thanks. — Preceding unsigned comment added by User109012 ( talk • contribs)
  • That's an animal study. Seppi333 ( Insert 2¢) 15:45, 24 January 2019 (UTC)