Overview
Caffeine is one of the most popular psychostimulants legally consumed. Psychostimulants are substances that alter the mood and behavior of a person.
Caffeine is majorly present in coffee, tea, energy drinks, and chocolates.
Caffeine produces a small rise in dopamine levels in the brain. Dopamine is called the happy hormone. This is why you feel ‘happy/good’ when you drink a cup of coffee or tea.
While some individuals feel active, happy, and energetic after consuming caffeine, others feel anxious, uncomfortable, and stressed.
The difference lies in how your body metabolizes caffeine. Metabolism is the process of converting the food you eat into energy.
Caffeine Metabolism At Its Molecular Level - Getting Technical
When you consume caffeine, it enters the bloodstream through your mouth, throat, and stomach. The tissues that line your blood vessels, skin, and organs let caffeine pass through quite easily.
It takes just a few minutes for the caffeine to be fully absorbed by the human body. The peak levels of caffeine in the plasma are reached in just 30 minutes.
The liver breaks down caffeine with the help of certain enzymes.
Half-life is the amount of time it takes for caffeine to be reduced to half its initial levels. The half-life of caffeine is about 4 hours. The half-life can increase or decrease depending on both genetic and non-genetic factors.
Caffeine easily crosses the blood-brain barrier. The structure of caffeine is similar to that of adenosine. Adenosine helps the brain relax and sleep. Adenosine receptors usually absorb adenosine. Caffeine attaches itself to the adenosine receptors. This prevents adenosine from acting and keeps people active and fatigue-less.
People develop a better tolerance for caffeine when they consume it regularly.
Apart from developed tolerance, other factors like genetics, age, lifestyle, and diet also affect the rate of metabolism of caffeine.
How Does Genetics Influence Caffeine Metabolism
CYP1A2 gene
The CYP1A2 gene produces the CYP1A2 enzyme. This is responsible for breaking down drugs, hormones, and other chemicals in the body to help retain essential parts and eliminate waste.
This enzyme plays an important role in caffeine metabolism. There are a few types of variations in this gene that affects how your body responds to caffeine.
rs762551 of CYP1A2 Gene and Caffeine Metabolism
The rs762551 SNP is the most discussed variation in the CYP1A2 gene. The AA genotype of this SNP is associated with faster metabolism of caffeine. Individuals with the AA genotype process caffeine quickly and may not experience the negative side-effects of caffeine consumption.
Both the AC genotype and the CC genotype individuals are slow metabolizers. They experience the unpleasant side effects of caffeine consumption, and their bodies process caffeine very slowly.
rs11854147 of CYP1A2 Gene and Caffeine Metabolism
Another SNP that causes an increase/decrease in caffeine metabolism is the rs11854147. Those with the CC genotype metabolize caffeine very rapidly and may not be affected by the negative effects of caffeine consumption.
The CT and the TT genotype individuals are slow metabolizers. They may be prone to the side-effects of caffeine consumption.
Non-genetic Factors Affecting Caffeine Metabolism
Liver diseases - Many studies relate liver diseases to lowered caffeine metabolism. People with liver diseases like liver cirrhosis, hepatitis B, or hepatitis C have lowered plasma clearance rates of caffeine. The more severe your liver disease is the lower the caffeine metabolism rate.
Weight - Caffeine metabolism also depends on body weight. Leaner individuals can increase their calories burnt by 30% when compared to overweight individuals (increase calories burnt by 10%) when they consume caffeine.
Diet - Few types of foods increase or decrease caffeine clearance in the body. Eating such food before you consume caffeine can make changes in caffeine metabolism.
Grapefruit decreases caffeine clearance by about 23%
Broccoli increases caffeine clearance in the plasma
Fruits and vegetables rich in flavonoid affects caffeine metabolism rates
Smoking - Smoking clears caffeine from the body very quickly. Smokers have very high caffeine metabolism rates and can usually handle high amounts of caffeine easily.
Some smokers have almost two times caffeine metabolism rates than non-smokers.
Pregnancy - During the third trimester, the enzyme that helps in caffeine metabolism reduces, increasing the half-life of caffeine. Your body processes caffeine very slowly until delivery, and the metabolism gets better after the child is born.
Medications - Drugs like Ephedrine are recommended to speed up the nervous system. Ephedrine and caffeine can work together and cause extreme jitters, nervousness, and anxiety. Similarly, certain antibiotics and estrogen pills can alter caffeine metabolism and need to be consumed with caution.
Effects of Slow Caffeine Metabolism
For slow caffeine metabolizers, it takes longer for caffeine to pass through the body, and hence the effects of caffeine are more. Such individuals have to restrict their caffeine intake. Here are some of the effects of slow caffeine metabolism.
-Insomnia
-Anxiety
-Digestive troubles
-Upset stomach
-Increased caffeine intake increases the risk of high blood pressure and heart attacks
Effects of Rapid Caffeine Metabolism
For rapid/fast caffeine metabolizers, the caffeine in the body quickly passes through the system. They are hence not affected by the side-effects of caffeine like slow metabolizers. Here are the effects of rapid caffeine metabolism.
-Increased weight loss
-Improved energy levels
-Improved physical performance
-Lowered risks of type II diabetes
-Improved mood and mental state
With time, people can identify the amounts of caffeine that they are comfortable with.
Start with smaller doses and keep a note of how you feel after you consume caffeinated drinks and beverages.’ Self-regulation works well in preventing caffeine overdose.
Recommendations To Improve Caffeine Metabolism
-It is very important you understand how your body processes caffeine. Get your genetic testing done to see if your genes affect the way your body deals with caffeine. If so, increase/decrease your caffeine intake accordingly.
-If your body handles caffeine normally, then do not go beyond the generally recommended levels. Do understand that packaged energy drinks, coffees, and flavored teas all have excess sugar along with caffeine. This is further unhealthy for your body.
-If you are hypersensitive to caffeine, try consuming less than 100 mg of caffeine a day to prevent ruining your metabolic system.
-For those whose bodies process caffeine very slowly, spacing out caffeine intake helps prevent overdoses.
-Staying physically fit, keeping your body hydrated, and eating healthy and fresh produce are all ways to improve your general metabolism. This ensures you can handle caffeine better.
Summary
- Caffeine metabolism is the act of how caffeine is processed by the body.
- Slow caffeine metabolism and rapid/fast caffeine metabolism are two common ways in which people process caffeine.
- Slow metabolizers are more affected by the unpleasant side effects of caffeine as caffeine stays in the body for a longer time.
- Fast metabolizers can process caffeine quickly in the body and hence can handle caffeine much better. They are benefitted from caffeine intake.
- Certain non-genetic factors like the presence of diseases, pregnancy, consumption of certain types of foods, and habits like smoking can change the way caffeine is metabolized in the body.
- Genetically, variations in the CYP1A2 gene can make people more/less sensitive to caffeine.
References
https://archives.drugabuse.gov/blog/post/caffeine-really-addictive
https://pubmed.ncbi.nlm.nih.gov/22302887/
https://medium.com/@viterenergy/3-ways-caffeine-boosts-your-metabolism-d64208b7fbb1
https://www.hsph.harvard.edu/nutritionsource/caffeine/
https://www.caffeineinformer.com/caffeine-metabolism
https://www.coffeeandhealth.org/topic-overview/caffeine-and-metabolism/
https://www.healthline.com/nutrition/caffeine-addiction#TOC_TITLE_HDR_9
https://www.mhc.wa.gov.au/media/1223/caffeine-the-facts-booklet.pdf"
