Caffeine is the most commonly consumed stimulant throughout the world. People consume caffeine through coffee, tea as well as energy drinks and chocolate to enhance their alertness. However, in general, people respond to caffeine in dramatically different ways since one person might become highly alert after one cup, yet others show little reaction despite multiple cups. Caffeine creates different effects in people because of what combination of genetic makeup, metabolic processes, brain chemistry and other individual characteristics each person possesses. Let's see how...
What is caffeine and how does it work
Caffeine functions by blocking brain chemicals, known as adenosine. The chemical adenosine produces tiredness in the body through reduced nerve system activity. The blocking of adenosine by caffeine results in elevated nerve activity that generates increased alertness together with energy and potentially anxiety and jitters. The brain releases two stimulating neurotransmitters dopamine and norepinephrine, which help boost focus while improving mood. The effects of caffeine depend on both the rate at which your body breaks down the substance, and your brain's sensitivity to it.
The role of genetics
Caffeine produces different effects on people because of a gene named CYP1A2. A liver enzyme controlled by the CYP1A2 gene, breaks down caffeine. The different versions of this gene determine whether someone metabolises caffeine quickly, or slowly.
Video
Fast metabolizers: These people break down caffeine quickly. People who metabolise caffeine fast experience less pronounced effects from the substance, while remaining able to consume coffee without sleep problems throughout the day.
The slow metabolizers process caffeine at a slower rate, so the substance remains active in their bloodstream for longer periods. The extended exposure to caffeine in their system results in stronger side effects including jitters, anxiety and sleep disturbances. A late-day caffeine intake leads to sleeplessness for these individuals.
The CYP1A2 gene variations between individuals explain why one person can drink coffee at night without sleep issues, while another person becomes too sensitive to caffeine even during daytime. The main reason for enzyme activity variation stems from genetic differences, although smoking and diet together with specific medications can also influence this enzyme. The main cause of variability stems from genetic differences.
The role of Adenosine receptors
Brain sensitivity towards caffeine along with metabolism, also determines the final effects caffeine produces in the body. Caffeine blocks brain adenosine receptors, yet individuals possess genetic variations in these receptors. The ADORA2A receptor functions as an example.
People who have certain ADORA2A gene variants experience heightened caffeine sensitivity, which leads to anxiety and sleep disturbances.
These individuals possess less responsive receptors, so they can handle caffeine without experiencing adverse effects.
The way brains react to caffeine stimulation can differ between two people who break down caffeine at the same speed.
Other factors
Additional factors besides genes contribute to how caffeine impacts different people.
Older adults require longer time to process caffeine, because their metabolism becomes slower.
Hormonal changes affect caffeine breakdown in the body with birth control pill users metabolising caffeine at reduced speed.
Pregnancy: Caffeine clearance slows during pregnancy.
Regular consumption of caffeine leads to tolerance development
Lifestyle: Smoking speeds up caffeine metabolism, meaning smokers break down caffeine faster than non-smokers.
The breakdown of caffeine changes in people with certain liver diseases, or who take specific medications.
Why this matters
Your understanding of how caffeine impacts your body, will guide you to decide when and how much caffeine you should use. People who metabolise caffeine slowly or have sensitive adenosine receptors should restrict their caffeine intake before evening hours because it causes sleep disturbances and anxiety. Fast metabolizers experience minimal negative effects when they consume caffeine.
Genetics related to caffeine metabolism also create risks for heart disease thus requiring doctors to take both caffeine use and genetic factors into account in patient care.
Sources
Yang, A. (2010). Genetics of caffeine consumption and responses to caffeine. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC4242593/
Northwestern Medicine. (2016). Java gene study: not everyone responds to coffee in the same way. https://news.northwestern.edu/stories/2016/10/java-gene-study-links-caffeine-metabolism-to-coffee-consumption-behavior/
Kapellou, A., et al. (2023). Genetics of caffeine and brain-related outcomes. Oxford University Press. https://pubmed.ncbi.nlm.nih.gov/37029915/
23andMe. (2022). Caffeine Consumption & Genetics. https://www.23andme.com/topics/wellness/caffeine-consumption/
Pfizer. (2021). Coffee Doesn't Give You the Jitters, Alcohol Makes You Blush. https://www.pfizer.com/news/articles/coffee-doesn%E2%80%99t-give-you-jitters-alcohol-makes-you-blush-thank-your-genes
Mahdavi, S., et al. (2023). CYP1A2 Genetic Variation, Coffee Intake, and Kidney Outcomes. JAMA Network. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2800839
Disclaimer: This article is informational only and not a substitute for medical advice
What is caffeine and how does it work
Caffeine functions by blocking brain chemicals, known as adenosine. The chemical adenosine produces tiredness in the body through reduced nerve system activity. The blocking of adenosine by caffeine results in elevated nerve activity that generates increased alertness together with energy and potentially anxiety and jitters. The brain releases two stimulating neurotransmitters dopamine and norepinephrine, which help boost focus while improving mood. The effects of caffeine depend on both the rate at which your body breaks down the substance, and your brain's sensitivity to it.
The role of genetics
Caffeine produces different effects on people because of a gene named CYP1A2. A liver enzyme controlled by the CYP1A2 gene, breaks down caffeine. The different versions of this gene determine whether someone metabolises caffeine quickly, or slowly.
Video
Fast metabolizers: These people break down caffeine quickly. People who metabolise caffeine fast experience less pronounced effects from the substance, while remaining able to consume coffee without sleep problems throughout the day.
The slow metabolizers process caffeine at a slower rate, so the substance remains active in their bloodstream for longer periods. The extended exposure to caffeine in their system results in stronger side effects including jitters, anxiety and sleep disturbances. A late-day caffeine intake leads to sleeplessness for these individuals.
The CYP1A2 gene variations between individuals explain why one person can drink coffee at night without sleep issues, while another person becomes too sensitive to caffeine even during daytime. The main reason for enzyme activity variation stems from genetic differences, although smoking and diet together with specific medications can also influence this enzyme. The main cause of variability stems from genetic differences.
The role of Adenosine receptors
Brain sensitivity towards caffeine along with metabolism, also determines the final effects caffeine produces in the body. Caffeine blocks brain adenosine receptors, yet individuals possess genetic variations in these receptors. The ADORA2A receptor functions as an example.
People who have certain ADORA2A gene variants experience heightened caffeine sensitivity, which leads to anxiety and sleep disturbances.
These individuals possess less responsive receptors, so they can handle caffeine without experiencing adverse effects.
The way brains react to caffeine stimulation can differ between two people who break down caffeine at the same speed.
Other factors
Additional factors besides genes contribute to how caffeine impacts different people.
Older adults require longer time to process caffeine, because their metabolism becomes slower.
Hormonal changes affect caffeine breakdown in the body with birth control pill users metabolising caffeine at reduced speed.
Pregnancy: Caffeine clearance slows during pregnancy.
Regular consumption of caffeine leads to tolerance development
Lifestyle: Smoking speeds up caffeine metabolism, meaning smokers break down caffeine faster than non-smokers.
The breakdown of caffeine changes in people with certain liver diseases, or who take specific medications.
Why this matters
Your understanding of how caffeine impacts your body, will guide you to decide when and how much caffeine you should use. People who metabolise caffeine slowly or have sensitive adenosine receptors should restrict their caffeine intake before evening hours because it causes sleep disturbances and anxiety. Fast metabolizers experience minimal negative effects when they consume caffeine.
Genetics related to caffeine metabolism also create risks for heart disease thus requiring doctors to take both caffeine use and genetic factors into account in patient care.
Sources
Yang, A. (2010). Genetics of caffeine consumption and responses to caffeine. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC4242593/
Northwestern Medicine. (2016). Java gene study: not everyone responds to coffee in the same way. https://news.northwestern.edu/stories/2016/10/java-gene-study-links-caffeine-metabolism-to-coffee-consumption-behavior/
Kapellou, A., et al. (2023). Genetics of caffeine and brain-related outcomes. Oxford University Press. https://pubmed.ncbi.nlm.nih.gov/37029915/
23andMe. (2022). Caffeine Consumption & Genetics. https://www.23andme.com/topics/wellness/caffeine-consumption/
Pfizer. (2021). Coffee Doesn't Give You the Jitters, Alcohol Makes You Blush. https://www.pfizer.com/news/articles/coffee-doesn%E2%80%99t-give-you-jitters-alcohol-makes-you-blush-thank-your-genes
Mahdavi, S., et al. (2023). CYP1A2 Genetic Variation, Coffee Intake, and Kidney Outcomes. JAMA Network. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2800839
Disclaimer: This article is informational only and not a substitute for medical advice
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