Some people metabolise coffee faster than others
This study may hold some clues why some people cannot do without coffee while for others it is a drink that keeps them awake at nights.
Coffee drinkers fall into one of three major groups based on their caffeine sensitivity, according to a new report by the Institute for Scientific Information on Coffee.
The report, Genetics, Metabolism and Individual Responses to Caffeine explains how the body metabolises caffeine and why some people are more affected by caffeine than others.
Response to caffeine is likely determined by two main genetic factors. One is whether the individual’s liver can metabolise caffeine quickly or slowly; and whether they carry a genetic variation that makes their central nervous system more sensitive to caffeine’s stimulatory effects.
People with slow-metabolism in the liver and high binding in the central nervous system are highly sensitive to caffeine and even a small dose of coffee may cause sleep disturbances in them.
Regular sensitivity to caffeine allows some people to drink 2-5 cups of coffee during the day without any problems. Fast metabolisers of coffee can tolerate higher intake of coffee
Regular sensitivity to caffeine allows some people to drink 2-5 cups of coffee during the day without any problems. Fast metabolisers of coffee can tolerate higher intake of coffee and their sleep is not disturbed by drinking a cup of coffee before bedtime.
However, no more than five cups of coffee per day is advisable according to the EFSA (European Food Safety Authority) guidelines.
“It’s common for people to ask their doctor questions such as why they are kept awake by one cup of coffee, while their partner easily falls asleep after five cups. The answer is that we are all unique coffee drinkers. Our genetic make-up programmes our reaction to caffeine, just as it programmes our hair colour and eye colour,” said Dr J. W. Langer, physician and author of the report.
The typical effects of caffeine, such as wakefulness, alertness, and increased concentration will not be seen in a person with low sensitivity to caffeine and fast metabolisers therefore, should not exceed the recommended daily caffeine intake trying to achieve the desired effects.
Other non-genetic factors such as smoking status, pregnancy, and age may also affect individual’s response to coffee intake and Dr Langer noticed that “Most people will self-moderate their caffeine intake based on their personal experience of what they can tolerate. However it’s important that those with a low sensitivity to caffeine stay within the recommended daily caffeine intake of up to 400mg caffeine, which is equivalent to around five cups of coffee.”
