[Functional Food] Coffee (part 2)

June 29, 2022

While coffee do not deserve the bad rap it gets, at the same time, it is also not the perfect food without flaw. We might have heard of people suffering insomnia, shaky hands and stomachache by drinking coffee. But is it all coffee’s fault? On the other hand, is there anything we could do to minimize such occurrence while enjoying a cup of coffee?

The 3 Principles to drink coffee healthily

1. Not on empty stomach

2. Not too much

3. Not too late

Question about Principle 1: Why not on empty stomach?

Coffee on empty stomach “stresses your body” by elevating your cortisol level quickly, not to mention cortisol level in the morning have already been the highest naturally throughout the day. High cortisol could lead to shaken hands, increased heart rate or blood pressure of an individual after drinking coffee on empty stomach. Moreover, coffee stimulates gastric acid release, which could lead to bloating and vomiting.

Question about Principle 2. How much is too much?

According to The European Food Safety Authority (EFSA), single doses of caffeine from 200mg to 400mg (2-4 cups of coffee) DO NOT raise safety concerns for adults. For pregnant and breast-feeding women, daily intakes of 200mg (2 cups of coffee) caffeine DO NOT raise safety concerns for the unborn/ breast-fed child and breast-feeding women.

According to the Centre for Food Safety, the caffeine content of coffee and tea drinks are as below:

Drinks ItemMean (mg)Range (mg)
CoffeeRegular Coffee200110 – 380
Coffee Espresso9762 – 170
Coffee Cappuccino11055 – 160
Coffee Caffe Latte9054 – 140
TeaLocal cafe style milk tea17073 – 220
Tea Taiwanese style milk tea130100 – 160

Question about Principle 3. When is too late?

You have to test it yourself because it depends on the individual’s ability to metabolize caffeine. Some people suffer from insomnia by just having a cup of coffee in the afternoon, and some people seem to be unaffected at all even with a cup of coffee at night. It turns out that the time it takes to metabolize and remove caffeine in the body varies from person to person. Common factors of caffeine metabolism rate are:

  1. CYP1A2 gene
  2. Pregnancy
  3. Smoking and Alcohol drinking
  4. Hormone drugs
  5. Age

For example, an adult needs an average of 5 hours to clear 50% of caffeine in the body while it takes more than 5 days for a newborn baby to do the same. It is recommended to place an order with the request of “half-shot” if you are caffeine-sensitive and try to drink it at noon or around lunchtime.

Coffee – The Misunderstood

Excess of anything is bad, that is true for many “healthy foods” and coffee as well. We all should be aware that excess coffee could be a problem because caffeine takes time to be metabolized in our body. However, at the same time, we should also not overlook coffee has been studied extensively, positively recognized by scientific research:

 “Coffee consumption was often associated with benefit than harm.” – UK British Medical Journal (BMJ)
An umbrella review by the UK British Medical Journal (BMJ) systematically evaluated more than 200 previous research and found that coffee consumption was often associated with benefit than harm. Coffee drinking is good for a range of health outcomes (e.g. cardiovascular disease, cancers, neurological and liver conditions).

“Coffee drinking can be a part of healthy diet.” – US Annual Review of Nutrition
Another umbrella review by the US Annual Review of Nutrition that evaluated more than 100 previous research found that coffee was associated with a decreased risk of cardiovascular disease, cancers, Parkinson’s disease and type-2 diabetes. Coffee drinking can be a part of healthy diet.


Centre for Food Safety, FDA, Victorian Government’s Better Health Channel, PMID: 29167102, 28826374, 23819683, 34966282, 30347020, 25041334, 23535278, 8604958, 23819683, Medicover Hospitals