Influence of genetics on consumption and response to caffeine
Article:
http://eds.b.ebscohost.com/eds/pdfviewer/pdfviewer?sid=7e2721db-52c1-4752-84ca-fffe1b6a8e6d%40sessionmgr120&vid=9&hid=112
Caffeine is the highest consumed psychoactive substance with 90% consumption in U.S. adults. It is globally popular due to it's ability to create alertness, enhance mood and stimulate the brain. It is also used clinically to treat problems like sleep apnea. According to this article, there are negative effects of caffeine such as excessive urination, bronchodilatation (decreasing resistance in the respiratory airway) and high systonic blood pressure. Low doses of caffeine induce mind euphoria, alertness and enhanced cognition. But high doses produce nausea, anxiety, trembling and jitteriness. Tolerance develops so quickly that the effects of caffeine in habitual consumers are different from occasional caffeine drinkers. One can develop physical dependence and strong withdrawal symptoms.
Last year I worked in a coffee shop that gave me free access to as much caffeine as I wanted. Once I stopped working there, I suffered from horrible headaches that turned into migraines. My mother is a nurse who thinks that there are worse negative effects of caffeine on African Americans than on Caucasian Americans. In order to test her hypothesis, I'm interested in the genetic influence of caffeine on different individuals.
This article reviews 3 things in order to come to a conclusion. It views twin studies on the genetic effects of caffeine, it reviews studies on pharmaccokinetic and pharmacodynamic variations in acute response, and it discusses the long term effects of caffeine.
There are huge differences in individual response to caffeine. Some experience anxious effects while others experience sleep disturbances and insomnia. Caffeine can also aggravate anxiety and panic disorder. On the metabolic level, there are drug receptors that contribute to the quality and magnitude of direct drug effects as well as to consumption of the drug. Some individuals may be more susceptible to long term negative health effects of caffeine. There are several factors that contribute to individual differences in responses such as age, demographics, environmental factors and sleep hygiene. Genetics can influence the body's adaptive response to long term caffeine use. Genetics can also influence the psychological and physiological processes that are related to drug effects. The article states that caffeine consumption changes through different stages in life. A best-fit model showed that family environment accounts for most of the variance in caffeine use from ages 9 to 14. Genetic contributions become more pronounced throughout adolescence and then stabilizes in adulthood.
Researchers conducted twin studies to compare the heritability of consumption and of caffeine induced insomnia and anxiety. Several twin studies showed a significant genetic contribution to determining caffeine intake. Caffeine consumption was found to have a heritability of 42% and heavy consumption, defined as >625 mg of caffeine daily, had a heritability of 77%.
Association studies linked genetic polymorphisms (This means the phenotype of each individual is determined by genetics) of metabolic enzymes and target receptors to variations in caffeine responses. They did a case control study to examine the relationship between these polymorphisms and targeted receptors with variations in caffeine responses to risks of Parkinson's and cardiovascular diseases in habitual caffeine consumers. Genome association studies linked adenosine and dopamine receptors to caffeine induced anxiety and sleep disturbances. This is also linked to the risk of myocardial infarction in caffeine user. They concluded that there are genetic variations in caffeine metabolism and the target dopamine and adenosine receptors.
There is a genetic predisposition to negative and positive effects of caffeine such a a susceptibility to withdrawal and imbalanced sleep. A survey was conducted based on the DSM-IV criteria for caffeine withdrawal, and they found that on average, women reported slightly higher levels of caffeine induced insomnia and sleep disturbances. Related studies were done to compare the genetic predisposition to caffeine use in relation to substance use in general. Studies show that smokers are more likely than non smokers to drink coffee. Heritability for caffeine use was not correlated to that of alcohol, nicotine and illicit drug use. But it did overlap with that of nicotine and alcohol by 72%.
This article is relevant to most college students and adults with full-time jobs. I cannot believe that 90% of American are coffee drinkers. This article and your thorough analysis has made me reevaluate the way I abuse caffeine. I am wondering myself if the benefits of coffee really outweigh the detriments. There have also been some recent Harvard studies on how caffeine, coffee in particular, can help reduce the risk of tinnitus and type 2 diabetes. I loved this article because I love caffeine. Excellent work!
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This blog was excellent and did a good job showing the differences that caffeine can have on different individuals! At the age of 14 I started drinking coffee to stay awake and attentive during my job and high school classes. Any day that I didn't drink coffee I noticed an unbearable headache that would take hours to go away if I didn't drink my coffee. Because of that I quickly stopped drinking coffee to avoid any pain on the days that I couldn't drink coffee. Now, my younger brother drinks coffee nonstop and on days or weeks where he can drink it, it doesn't effect him the way it did for me. Furthermore, For me I would feel it kick in hours after I drank it and for him it seemed to kick in instantly. So it appears to have drastically different effects depending on the person.
ReplyDeleteThis article as well as your analysis was very interesting to read. I never would have guessed that responses that each individual has after consuming caffeine would be based off of genetics. Factors such as age, environmental factors, and sleep hygiene did not come as a surprise to me when thinking of how caffeine could produce different bodily responses. Typically when it comes to age, from experience and from observation, it seems that caffeine is a widely used stimulant used to provide alertness. Any time I had an assignment due in high school, the first thing on my mind would be to go make a pot of coffee! Now in college, I still rely on caffeine to get me through days when I haven’t had enough sleep to keep me awake in class or even at work. I have friends that cannot live without caffeine! It’s to the point where one of my friends has to have some form of caffeine or she will have migraines, just as you spoke about. I find this interesting because as much as I consume caffeine, it does not seem to have the same effect on me as it does on my peers. I now question after reading this if it could be because of genetic factors that I do not experience these bodily responses or if there could potentially be another factor that has caused my bodily responses to differ from my peers.
ReplyDeleteBeing one of the few college students who do not drink coffee, I found this article and its stats extremely surprising. Every day I pass the Starbucks it blows my mind how many people are standing in line for coffee in the mornings. I have noticed through my friends the different effects it can have but I never knew these effects were influenced by genetics. I found this shocking because these effects are evolutionary and happen due to adaption over time. Another fact I pulled out of the article was how Americans consumed so much caffeine making it the highest consumed psychoactive substance currently. It came as a surprise that the tolerance can develop so quickly that the effects of caffeine in habitual consumers are different from occasional caffeine drinkers. One can develop physical dependence and strong withdrawal symptoms. This stood out to me because I personally know a bunch of people who drink coffee daily, and “can’t go without” their morning coffee. This made me want to dig deeper into the topic and see if genetics would play a part in people’s responses if their caffeine intake was cut off completely? Would some races have less sever withdrawals due to evolution and what would be the genetic health effects if this happened? Overall, I found this article highly informative and full of interesting facts I never knew about.
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