COFFEE × CAFFEINE
The relationship between coffee, caffeine, and the body.
I am often asked, “How many cups of coffee can I drink a day?”
To put it simply, because the appropriate amount of caffeine varies from person to person, there is no single answer.
While it is widely known that coffee contains a lot of caffeine, its actual effects on the body are not well understood. Here, I will briefly and concisely explain the latest information based primarily on studies involving Japanese people, as well as several meta-analyses conducted internationally.
First, caffeine sensitivity varies from person to person. In other words, everyone has a different tolerance level. Therefore, you first need to know which group you belong to.
Caffeine sensitivity
1. High caffeine sensitivity = People who experience side effects such as insomnia or anxiety even with 100 mg or less
2. Moderate caffeine sensitivity = People who experience side effects when consuming more than 200–400 mg
3. Low caffeine sensitivity = People who do not experience side effects even when consuming large amounts
People can generally be divided into these three groups, but because there are individual differences, please consider these as rough guidelines.
For those in group 1, limit yourself to 1 cup a day. For those in group 2, limit yourself to 3–4 cups. Those in group 3 can consume 5 or more cups without problems, but everyone has a limit, so overconsumption is not recommended.
Side effects include palpitations, headaches, sleep disorders, anxiety, and restlessness.
According to a meta-analysis involving approximately 90,000 Japanese people, those who drink coffee every day (including decaf) have a lower risk of all-cause mortality than those who do not drink coffee at all.
Reduction in all-cause mortality risk from coffee consumption
Average of 1 cup or less per day = 9%
2 cups = 15%
3–4 cups = 24%
5 or more cups = 15%
In all cases, the results showed a reduced risk of all-cause mortality compared to those who do not drink coffee at all. In addition to caffeine, other compounds in coffee, such as polyphenols and chlorogenic acid, also have beneficial effects on the body. Representative benefits include a reduced risk of stroke, dementia, heart disease, and diabetes, as well as prevention of cancer and depression, anti-aging, and weight loss.
It may no longer be an exaggeration to call it a medicine you drink.
People who should cut back on coffee or switch to decaf
Pregnant women are thought to have higher caffeine sensitivity. Considering the potential effects on the fetus, you should minimize your intake or switch to decaf. People with high blood pressure should also be careful. Several studies have reported that caffeine can have adverse effects on people with high blood pressure. Those who suffer from insomnia should also avoid caffeine. Although there are individual differences, the half-life of caffeine is said to be 4–5 hours. In other words, if you consume 100 mg of caffeine, 50 mg will still remain in your body 5 hours later. Those in the high caffeine sensitivity group who suffer from insomnia may find it best to limit their coffee consumption to the morning or switch to decaf.
While excessive consumption of caffeine can be harmful, this is not unique to caffeine. I hope you can discover the right amount for you and enjoy coffee within that range.