Many of us can’t imagine starting the day without a cup of coffee; whether you're its a shot of strong, rich espresso or a simple instant with milk; there's something special about that first morning coffee. So, what makes us crave it?
Coffee contains a chemical called caffeine, which is a stimulant to the central nervous system that quickly boosts our alertness and energy levels. Caffeine is absorbed within about 45 minutes after consuming, and peaks in the blood anywhere from 15 minutes to 2 hours, and it can remain there from 1.5 to 9.5 hours.
People can develop a “caffeine tolerance” if they consume coffee regularly, and as a result, the caffeine’s stimulant effect is reduced. Furthermore, if you are used to drinking coffee every day, and you suddenly stop consuming it, withdrawal symptoms often follow such as irritability, headache, agitation, and fatigue.
What contains caffeine?
Caffeine is naturally found in coffee, tea and chocolate. Synthetic caffeine is then added to products such as soda, supplements and energy drinks to promote alertness, energy and mood.
One cup of coffee contains 95mg of caffeine. We can also find caffeine in tea which contains 47 mg of caffeine in one cup, in soda which contains 40 mg per serving, chocolate bar which contains 24 mg of caffeine, guarana (a South America plant) which contains up to 125mg of caffeine per serving, and finally in energy drinks which contain around 200 mg of caffeine per serving.
The recommended amount of caffeine consumption in the UK is 400 mg, which corresponds to 4 cups of coffee a day. For pregnant women, recommendations are 200 mg, which equate to two cups of coffee a day.
Energy drinks represent a particular issue for the general population, as they usually contain 200 mg of caffeine and excessive amount of sugar. Research studies have shown a negative association between the consumption of energy drinks and mental health status. For example, consuming energy drinks regularly leads to aggressive behaviour, increased stress, poor sleep quality as well as increased risk of developing obesity and type-2 diabetes. One of the main reasons why energy drinks cause special concerns, is attributed to the excessive caffeine content.
Side effects of caffeine:
Excessive caffeine intake is associated with
- heart problems such as irregular heartbeats and elevated blood pressure.
Of particular concern is the rate of caffeine intake among populations potentially vulnerable to its negative effects such as pregnant women, children and adolescents. Studies have shown that pregnant women consuming around 400 mg of caffeine a day have an increased risk of spontaneous abortion by 11% compared with women who consume <50 mg/day. This is attributed to the fact that caffeine crosses the placental barrier and alters the development of the foetus. Once caffeine enters the foetal circulation, it is metabolised slowly, as neither the placenta nor the foetus itself have the enzyme that metabolises caffeine.
Young children are also vulnerable to the effects of caffeine, because they weigh less, and they are small. Adolescents are considered another risk group, as they tend to use caffeinated beverages to stay awake. Excessive consumption of these beverages containing caffeine leads young adolescents to develop behavioural problems such as anger, violence, sleep disturbances and alcohol use. Moreover, patients with cardiac disease need to be careful with caffeine consumption, as acute intake of caffeine stimulates a modest increase in blood pressure, effects on heart rate and neuroendocrine effects.
Benefits of caffeine:
Caffeine has also beneficial properties, as it is rich in polyphenols, plant compounds which have a protective antioxidant effect. Moreover, caffeine increases alertness and wakefulness and improves performance on memory tasks. Finally, caffeine improves psychomotor vigilance such as reaction time. There are five main health benefits that caffeine provides:
Increase energy and performance: as a neurostimulator, caffeine maintains alertness and energy level and it improves athletic performance
Boost metabolism: caffeine improves weight management through boosting metabolic rate and burning fat. For this reason, caffeine is often used in the treatment of obesity, as it helps to suppress appetite and therefore prevents people from snacking on unhealthy foods.
Support brain function: there have been numerous studies suggesting that caffeine protects against neurodegenerative diseases. For example, a 21 year follow up study found that moderate consumption of coffee (<400 mg/day) reduces the risk of Alzheimer’s and dementia later in life. Another similar study found that patients drinking a cup of coffee everyday have a 60% reduced risk of developing Alzheimer’s disease.
Help with blood sugar balance: there is some evidence suggesting that coffee may lower the risk of developing type-2 diabetes, due to its caffeine content which maintains a normal level of glucose in the blood.
Help you live longer: coffee is not only part of your morning routine, but it may be part of a longer and healthier life. A study published in the Annals of Internal Medicine suggests that drinking up to 3 cups of coffee a day have a lower risk of dying from diabetes, heart disease and respiratory disease. The researchers concluded that consumption of coffee equates to a 10% reduction in overall death for men and 15% reduction in overall death for women.
Are there caffeine alternatives?
If you don’t like coffee, there are some great caffeine-free alternatives that you must try:
Chicory coffee, which is a warming drink made from the root of the chicory plant, which has anti-inflammatory properties;
Dandelion coffee, which is made from the root of the dandelion plant, and it has been associated with a reduced risk of having high cholesterol;
Barley coffee also known as mugicha in Japan, is a good source of protein and fibre and it has been linked to a reduced risk of heart disease.
Overall, caffeine has several beneficial properties, and it can help you to live longer and reduce the risk of developing type-2 diabetes, cardiovascular disease and neurodegenerative diseases.
However, it is important to bear in mind that a dose of caffeine greater than 400 mg/day can be dangerous. Vulnerable groups such as pregnant women, children and young adolescents are strongly recommended to reduce their caffeine intake compared with the general population.