Do you start your day with a cup of freshly brewed coffee? Does a cup of tea warm your insides and leave you feeling fresh in the evening? Do you stock up energy drinks in your fridge to help handle late nights?
All these beverages have one thing in common - caffeine.
Caffeine is an organic compound found in plant sources. Caffeine is a legally accepted and consumed psychoactive drug ( a chemical that alters nervous system functions). Caffeine alters a person’s mood, behavior, and energy levels.
While some studies have praised the beneficial effects of caffeine on human health, others warn about the health risks. Why does the same substance lead to different health outcomes?
The answer to these questions is not only applicable to caffeine but also to a lot of other substances.
We are all genetically unique. While some substances produce relatively similar effects on our bodies- many substances, including caffeine, are processed differently in different individuals.
When a drug fails a clinical trial- it does not mean that every individual who took that drug failed to respond. On the other hand, there is no approved drug that works equally well on every individual.
It is common knowledge that some drugs work really well for some, but not for others. We need higher doses of certain drugs and lower doses of others. There is a dose difference for certain drugs for men, women and children.
Caffeine is no different. Unless the genetics and other factors are accounted for, it will not be easy to say whether caffeine is good or bad for you. Keep reading to find out the unique genetic aspects of caffeine metabolism (processing in the body)
There are about 60 species of plants that can produce caffeine. Few top sources are:
Did you know that about 85% of Americans consume at least one caffeinated drink a day? Coffee remains the most consumed caffeinated drink among adults.
How much caffeine is too much? Do you have to give up on caffeine to lead a healthy lifestyle? Keep reading to know more.
The history of caffeine is closely associated with the histories of its plant sources.
It was 2437 BCE. The Chinese Emperor Shen Nung was relaxing in his garden. The wind blew a couple of leaves into his cup of boiling water. He noticed that the water changed color and smelled fragrant. The leaves were later identified to be from the tea shrubs. Tea leaves are considered a stimulant (a drink to energize the body).
There are many stories on the discovery of caffeine. Some scripts say the ethnic Oromo people of Ethiopia recognized coffee beans to have energizing properties.
The more popular version is of Kaldi, an Ethiopian goat herder. He noticed his goats getting all excited after consuming coffee beans. He mentioned this in a monastery and the first cup of coffee was brewed there.
The leaves of the yaupon holly tree were brewed as early as 8000 and 1000 BC. This was then known as the black drink.
In many West African cultures, it is still a regular practice to chew on kola nuts when people feel tired.
Caffeine is very easily absorbed by the body. 99% of caffeine is absorbed in about 45 minutes.
Once you consume a caffeinated beverage, it enters the gastrointestinal tract. Caffeine is processed in the liver by an enzyme that breaks it apart into different chemicals like paraxanthine, theobromine, and theophylline.
Peak levels of caffeine are observed in the plasma between 15 minutes and 120 minutes after oral consumption.
Caffeine easily reaches the brain. Adenosine is a chemical in the brain that induces sleep. The structure of caffeine is similar to that of adenosine. Caffeine attaches itself to the adenosine receptors (a protein that responds to adenosine) and prevents people from feeling sleepy.
The more caffeinated beverages you drink, the more adenosine receptors your body will produce.
Over time, you will need more amounts of caffeine to keep you awake.
Plant sources are not the only way to get your dose of caffeine. Caffeine is artificially synthesized in industries too.
The production of caffeine in industries began during World War II. Germans were unable to obtain caffeine because of various trading bans. They hence had to create caffeine artificially.
Today, synthetic caffeine is very cheap and tastes just like natural caffeine. It would not be surprising if you cannot tell the difference between the two.
While synthetic caffeine is safe when had in small amounts, the problem is with the manufacturing process. Ammonia goes through a lot of steps and chemical interactions to turn into caffeine.
The synthetic caffeine industry is also unregulated in most countries. All this makes synthetic caffeine a slightly worrying product in the market.
Caffeine is addictive. Your body goes through withdrawal symptoms when you try to reduce your caffeine intake. Few popularly noticed symptoms of caffeine withdrawal are:
Withdrawal symptoms can start 24 hours after giving up caffeine and can last for up to 9 days.
Caffeine sensitivity refers to having an adverse reaction to consuming caffeine. For most people, consuming more than 400 mg of caffeine can cause physical and mental discomforts.
Few others can be hypersensitive to caffeine and cannot tolerate it even in small quantities. Here are some non-genetic factors causing caffeine sensitivity.
How are some people able to process caffeine better than others? Genetics is the answer.
CYP1A2 gene - The CYP1A2 gene influences how fast caffeine is processed in your body and how you react to it. One particular SNP that can increase or decrease the effects of caffeine consumption is the rs762551.
AC and CC genotype
ADORA2A gene - The ADORA2A gene produces the adenosine receptors in the brain. You know by now that caffeine attaches itself to the adenosine receptors and prevents the person from feeling tired or sleepy.
The ADORA2A gene is also responsible for increasing dopamine levels (the happy hormone). Variations in the ADORA2A gene are said to cause mood swings, anxiety, and irritation.
Caffeine is a legally consumed drug that can alter the mood and increase attention and focus. It is naturally present in up to 60 plant sources. It is also artificially produced in industries. Normal adults have to limit their caffeine intake by up to 400 mg. Caffeine overdose can lead to mood disorders, rapid heartbeats, and high blood pressure. Caffeine withdrawal has to be handled gently and causes symptoms like depression, anxiety, and low energy levels. Genetically, some people can show high caffeine sensitivity and need to monitor their caffeine consumption.
CYP1A2 codes for the production of 21-hydroxylase, which is part of the cytochrome P450 family of enzymes.
This family of enzymes is quite important as it is a part of many processes, that include breaking down drugs, production of cholesterol, hormones, and fats.
The adrenal glands secrete the enzyme, 21-hydroxylase.
Situated on the top of the kidneys, the adrenal glands also produce hormones like epinephrine and cortisol.
Incidentally, 21-hydroxylase plays a role in the production of cortisol and another hormone named aldosterone.
Cortisol is a stress-related hormone and plays a role in protecting the body from stress, as well as reducing inflammation.
Cortisol also helps in maintaining blood sugar levels.
Aldosterone, also known as the salt-retaining hormone, regulates the amount of salt retained in the kidneys.
This has a direct consequence on blood pressure, as well as fluid retention in the body.
There seems to be an interesting trend in the activity of the CYP1A2 gene and caffeine intake.
The consequence of being a “rapid” or a “slow” metabolizer of caffeine can have effects on an individual’s cardiovascular health.
This article explains the wide-ranging effects of this gene, caffeine intake, cardiovascular health, hypertension, and even pregnancy!
In the body, CYP1A2 accounts for around 95% of caffeine metabolism.
The enzyme efficiency varies between individuals.
A homozygous, that is, AA genotype represents individuals that can rapidly metabolize caffeine.
Some individuals have a mutation in this locus and thus have the AC genotype.
These individuals are “slow” caffeine metabolizers.
There seems to be a link between CYP1A2, the incidence of myocardial infarction (MI), and coffee intake.
The positive effects of coffee include lowering a feeling of tiredness and increasing alertness; however, it can also narrow the blood vessels.
This increases blood pressure and could lead to cardiovascular disease risk.
Rapid metabolizers of coffee have the AA genotype and may unravel the protective effects of caffeine in the system.
However, the individuals that are slow metabolizers have a higher risk of MI.
This suggests that the intake of caffeine has some role in this association.
Yet another study associated DNA damage due to mutagens found in tobacco smoking could contribute to MI.
The study included participants who were genotyped at the CYP1A2 gene.
They found a group of ‘highly inducible’ subjects that had a CYP1A2*1A/*1A genotype.
These individuals have a greater risk for MI, independent of their smoking status.
This also means that there is some intermediary substrate that the CYP1A2 gene decomposes, and if this gene has a mutation, it could lead to a higher risk of MI.
In a study conducted on 2014 people, people who were slow metabolizers of caffeine (C variant) and who consumed more than 3 cups of coffee per day had an association with increased risk for myocardial infarction.
In a similar study on 513 people, increased intake of coffee, among slow metabolizers, has an association with an increased risk for hypertension.
Smoking is capable of inducing the CYP1A2 enzyme. Smokers exhibit increased activity of this enzyme.
In a study conducted on 16719 people, people with the A variant, and who were non-smokers, were 35% less likely to be hypertensive than people with the C variant.
In the same study, CYP1A2 activity had a negative association with blood pressure among ex-smokers.
But for people who were still smoking, the same gene expressed an association with increased blood pressure.
The gene CYP1A2 also has an association with caffeine metabolism and smoking.
A study aimed to tie these concepts together to find the relationship between this gene and blood pressure (BP).
The main measurements of the study were caffeine intake, BP, and the activity of the CYP1A2 gene.
In non-smokers, CYP1A2 variants (having either a CC, AC, or AA genotype) were associated with hypertension.
Higher CYP1A2 activity was associated with people who quit smoking and had lower BP compared to the rest but had a higher BP while smoking.
In non-smokers, CYP1A2 variants (having either a CC, AC or AA genotype) were associated with high caffeine intake, and also had low BP.
This means that caffeine intake plays some role in protecting non-smokers from hypertension, by inducing CYP1A2.
The intake of caffeine during pregnancy has an association with the risk of reduced fetal growth.
High caffeine intake shows a link to decreased birth weight.
The babies are also at risk of being too small during the time of pregnancy.
This was also observed in a study conducted on 415 Japanese women.
Women with the A variant who drank more than 300 mg of coffee per day were shown to be at an increased risk of giving birth to babies with low birth weight.
In conclusion, there are a lot of effects that the CYP1A2 gene has on the body. Many studies, as noted above, seem to link the activity of this gene to caffeine intake.
A variant at the CYP1A2 gene can determine whether an individual is a fast or slow metabolizer of caffeine, and this has some effect on the blood pressure and cardiovascular health of an individual.
The gene also plays a role in regulating an infant’s weight during the pregnancy of a woman, and this has a link with caffeine intake. It is thus interesting to analyze the effect of the variants of the CYP1A2 gene on an individual, based on their caffeine intake.
Upload it to Xcode Life to know about your CYP1A2 caffeine metabolism and caffeine sensitivity variants.
Caffeine acts as a stimulant of the Central Nervous System (CNS), causing increased alertness.
It is the world's most widely consumed legal psychoactive drug.
Caffeine offers a range of benefits from something as small as over an afternoon slump to reducing the risk of some serious health conditions like heart diseases.
Some common food sources of caffeine include:
Up to 400 milligrams of caffeine appears to be safe for most healthy adults.
Anything exceeding that can be harmful to the body.
The effect of caffeine on various systems of the body are as follows:
Caffeine is a stimulant and causes mental alertness once it reaches the brain.
It is a common ingredient in medications that are meant to treat drowsiness, migraines, and headaches.
Caffeine stimulates the production of stomach acid and can cause heartburn, acid reflux, or stomach upset.
Excess caffeine is stored in the liver, which exits through urine.
Hence, drinking excessive coffee or tea increases the urge for urination.
Caffeine intake increases adrenaline production.
This, in turn, increases your blood pressure for some time.
When consumed in excess quantities, caffeine can lead to irregular heartbeat and breathing.
Excess caffeine interferes with the absorption and utilization of calcium.
Reduced calcium levels in the body can lead to osteoporosis.
Muscle twitching is often a visible symptom of excess caffeine consumption.
A little caffeine during pregnancy appears to be safe in most cases.
However, it is important to note that caffeine can cross the placental barrier, and therefore, can affect the fetus.
It can increase the fetus's heart rate and, in some cases, may even lead to a miscarriage.
CYP1A2 codes for a protein that belongs to the Cytochrome P450 family.
This protein is involved in the breakdown of stimulants, drugs, nutrients, and other xenobiotics.
The CYP1A2 gene regulates the synthesis of the enzyme, and small variations in this gene are associated with the efficiency of caffeine metabolism.
Some people are genetically predisposed to produce very little of CYP1A2 enzyme while others may generate a sufficient amount.
Approximately 10% of the population is found to be rapid caffeine metabolizers, showing a high tolerance to caffeine.
This enzyme is also essential for removing toxic chemicals from our body and processing hormones and other products of metabolism.
Both increased and decreased enzyme activity have been linked to an increased risk of cancer.
It is a significant protein family in the human body, as it majorly decides how an individual responds to drugs and nutrients.
Variations in this gene broadly divide people into two groups of metabolizers:
In particular, two Single Nucleotide Polymorphisms (SNP) are found to influence caffeine metabolism:
The haplotype CYP1A2*1F is associated with this variation.[table “100” not found /]
Individuals who have the TT genotype in this specific polymorphism of the CYP1A2 gene may be fast metabolizers of caffeine.
A study conducted on 553 individuals found that people with this genotype had a 70% reduction in the risk of a heart attack on increased consumption of caffeine.[table “101” not found /]
People of certain genetic types have a genetic predisposition to drink more cups of coffee.
Identification of this tendency will help in moderating coffee consumption, taking into account the individual's caffeine metabolism status.
Genetic tests can help identify such parameters.
After all, it would be good to know if you are prone to guzzling down a little too much, especially when your caffeine sensitivity scale is tipped at the wrong end.
Caffeine tolerance in an individual is gene deep.
The enzyme CYP1A2 is responsible for metabolizing caffeine in the body and determines whether the individual is a slow or a fast caffeine metabolizer.
Fast metabolizers of caffeine may have a high caffeine tolerance.
Such people have two copies of the fast variant.
Some people have one slow and one fast copy of the variant and are said to be moderately tolerant to caffeine.
However, those individuals who have two copies of the slow variant are slow metabolizers of caffeine and are said to be poorly tolerant of it.
Resting metabolic rate describes the rate at which you burn calories at rest.
A lot of studies vouch for caffeine boosting the RMR.
Early research also suggests that caffeine supports fat-burning during exercise.
This increase in fat-burn is what majorly contributes to the increase in metabolism.
Initially, the increase in metabolism upon caffeine consumption can be evident.
However, this effect can diminish in long-term coffee drinkers due to the developed tolerance.
If you're primarily interested in coffee for the sake of fat loss, it may be wise not to consume it excessively and end up making your body more tolerant of caffeine.
Caffeine is a component in many plants, including coffee and tea.
The primary purpose of it is to act as a toxin to defend the plants against herbivores.
Caffeine in limited quantities is beneficial to our health, but in excessive amounts, harmful.
The effects of excessive caffeine intake (more than 4-5 cups of strong tea or coffee) include:
Excessive caffeine consumption does come with a set of undesirable effects.
During such times, the following remedies can help flush out caffeine from the system:
If nothing else works, just wait! The half-life of caffeine in the human body is roughly 4-6 hours, which means caffeine naturally starts to breakdown after that time.
If your body is dependent on caffeine, eliminating caffeine from your diet may cause symptoms of withdrawal.
This occurs typically 12-24 hours after stopping caffeine.
Upload your DNA raw data to Xcode Life. Our Gene Nutrition Report analyses caffeine sensitivity and metabolism, gluten sensitivity, lactose intolerance, vitamin needs, and 33 more such categories.
It is hard to believe that caffeine, a stimulant that holds popularity in battling fatigue and improving creativity, can do any harm.
Caffeine sensitivity is a term that describes the efficiency of the human body to process caffeine and to metabolize it.
We have all heard of co-workers who drink 6 cups of coffee, the recreational drink for nearly 60% of Americans, every day, and friends who guzzle a cup an hour before bedtime.
Yet there are some of us who feel jittery, anxious, or even restless after a single cup.
So, is caffeine a scourge, a tonic, or a mix of both?
For starters, coffee has a few benefits.
A large research study showed that Americans get more antioxidants from coffee than from any other dietary source.
Other studies have shown that there are several nutrients in a cup of brewed coffee, like Magnesium, Niacin, and Potassium, depending on the soil nutrients and the type of processing.
Adenosine is an organic compound that inhibits arousal and promotes sleepiness upon binding to its receptor.
Caffeine has a structure similar to adenosine and works as an adenosine receptor antagonist.
It competes with adenosine to bind to the adenosine receptor.
This process promotes wakefulness.
Though this can affect the quality of sleep among certain people, it could help in situations like driving at night or averting jet lag, where mental alertness is critical.
According to the U.S. Food and Drug Administration (FDA), 300 milligrams of caffeine are consumed every day by the average American. The Mayo Clinic states that drinking up to 400 milligrams per day is safe, which is approximately 4 cups.
A good cup of coffee is the most popular caffeine delivery mechanism that comes with a few health benefits like being a good source of antioxidants, warding off liver disease, and protecting against Parkinson’s.
The health risks and benefits have been understood, over the years, however, caffeine and metabolism, or the way in which our body processes the chemical, varies on several key factors.
|Beverage||Caffeine content (mg)|
|Coffee||8 oz cup - 95 mg|
|Espresso||1 oz shot - 63 mg|
|Green tea||8 oz cup - 28 mg|
|Black tea||8 oz cup - 26 mg|
|Energy drinks||8 oz cup - 91 mg|
|Sodas (Cola)||16 oz cans - 49 mg|
|Coffee liqueur||1.5 oz shot - 14 mg|
|Dark chocolate||1 oz square 24 mg|
Caffeine, an alkaloid, is also known as 1,3,7-trimetilksantin.
It is acidic in its pure crystalline form and is found in over 60 plant species.
The enzyme CYP1A2 is responsible for the metabolism of caffeine in the liver.
Due to potentially ineffective CYP1A2 enzyme activity, some people can experience issues like caffeine jitters after 2-3 cups of coffee per day.
Such slower metabolizers of caffeine may experience problems with blood pressure, headaches, etc.
The CYP1A2 gene regulates the synthesis of the enzyme, and small variations in this gene have an association with the efficiency of caffeine metabolism.
Some people have a genetic predisposition to produce very little of CYP1A2 enzyme while others may produce a large amount.
Approximately 10% of the population is found to be rapid caffeine metabolizers, which rates them high on caffeine sensitivity.
Approximately 10% of the population are found to be rapid caffeine metabolizers, which rates them high on caffeine sensitivity.
The polymorphism associated with caffeine metabolism is rs762551.
Studies have shown that individuals with AC or CC genotypes are slow metabolizers of caffeine.
These individuals have a high caffeine sensitivity.
They tend to have a slightly increased risk for heart attack upon consumption of more than 2 cups of coffee every day.
Individuals who have the A.A. genotype in the specific polymorphism of the CYP1A2 gene may be fast metabolizers.
These individuals have a low caffeine sensitivity.
A study conducted on 553 individuals found that people with this genotype had a 70% reduction in the risk of a heart attack on increased caffeine consumption.
The polymorphism in the CYP1A2 gene is well studied and is useful to determine the caffeine metabolism status.
This, in turn, can shine some light on the tendency to consume caffeine.
The 23andMe reports provide caffeine metabolizer status.
There are other well known 23andMe third-party tools, like Xcode Life, that can provide a better understanding.
Upload your 23andMe raw data to find out your caffeine metabolism status.[table “44” not found /]
23andMe DNA raw data is the genetic information obtained after a genetic test, and it is usually provided as a text file.
This information can be downloaded after utilizing the 23andMe login provided to all 23andMe customers.
There is a wealth of information provided by ancestry DNA that can be used to identify a number of health and nutrition-based traits.
Use your ancestry DNA login to download your Ancestry DNA raw data.
You can then upload your Ancestry DNA raw data onto our site to identify the caffeine metabolizer status.
23andme vs. AncestryDNA vs. Xcode Life pertaining to caffeine metabolizer status[table “45” not found /]
People of certain genetic types tend to have a genetic predisposition to drink more cups of coffee.
Identification of this tendency will help in moderating coffee consumption, taking into account the caffeine metabolism status of the individual.
Genetic tests can help identify such parameters.
After all, it would be good to know if you are prone to guzzling down a little too much, especially when your caffeine sensitivity scale is tipped at the wrong end.