Caffeine
Caffeine occurs naturally in foods such as coffee, tea and cocoa and has a long history of use as a mild stimulant. In small doses, it can make you feel more alert, awake, clear-minded and able to concentrate. In large doses, it can make you feel anxious, affect your heart rate and cause runny poos (diarrhoea) and difficulty sleeping.
What caffeine is
Caffeine is a drug present in more than 60 plants, including:
- coffee beans
- tea leaves
- cocoa beans
- kola nuts
- guarana.
The caffeine in chocolate comes from cacao or cocoa beans, and the caffeine in cola drinks comes from kola nuts.
Caffeine is added to many soft drinks and energy drinks. It is also added to some supplements and some pain relief medications.
Always check the label of snack, muesli and sports bars as they may have cacao or guarana added.
Matcha and kombucha are made of tea, so they contain small amounts of caffeine.
How caffeine affects your body
Caffeine stimulates the brain and central nervous system. It blocks receptors for a type of neurotransmitter (chemical messenger) called adenosine. This is what causes the feeling of wakefulness, energy and focus.
Some people find that caffeine helps them stay alert and improves their energy levels and concentration.
Some people are more sensitive to caffeine, and having too much can cause problems such as:
- jitteriness
- trouble sleeping
- high blood pressure
- heartburn
- anxiety
- irritability
- dizziness
- headaches
- heart palpitations
- increased bowel movements or loose or runny poos.
Caffeine and pregnancy
If you are pregnant, having too much caffeine can increase your risk of having a miscarriage. It can also affect your pēpi’s growth and increase the risk of them having a low birth weight. Having a low birth weight can increase the risk of health problems later in life.
If you are breastfeeding, small amounts of caffeine can pass from your milk to your pēpi and build up in your pēpi over time. Having too much caffeine may make your pēpi irritable and cause sleeping issues.
Safe amounts of caffeine
Most adults can handle up to 400 mg of caffeine a day with no problems. This is about:
- 6 cups of tea
- 5 cups of instant coffee
- 4 cups of plunger coffee
- 2 double-shot espresso-style coffees.
If you are pregnant or breastfeeding, up to 200 mg of caffeine a day is safe for your unborn pēpi or breastfed infant.
Tamariki can have the same problems with caffeine as adults, but with much smaller amounts. It is best for tamariki not to have much caffeine, especially from energy drinks and cola drinks that also have a lot of sugar.
Caffeine levels in drinks and food
The caffeine content of coffee and tea made at home and at cafés can vary. It depends on the type of coffee or tea, serving size and brewing method.
Energy drinks and shots may contain other stimulants such as guarana, taurine and L-carnitine. These act in a similar way to caffeine.
The average caffeine content per serving:
- espresso coffee (double shot) — 210 mg
- plunger coffee (1 cup) — 100 mg
- energy drink (250 ml can) — 80 mg
- energy shot (60 ml) — 60 mg
- instant coffee (1 teaspoon) — 80 mg
- tea (1 cup) — 60 mg
- cola drink (330 ml can) — 35 mg
- green tea (1 cup) — 30 mg
- chocolate bar (50 g) — 30 mg
- energy gel (50 g) — 30 mg
- decaffeinated instant coffee (1 cup) — 6 mg
- drinking chocolate (1 cup) — 5 mg.
Caffeine and medications
Caffeine can interact with certain medicines, such as:
- antidepressants
- antipsychotics
- medications for your heart or thyroid function.
It can reduce their effectiveness and increase the risk of side effects.
Talk to your healthcare provider if you need advice on caffeine and any medications you are taking.
Tips for cutting down on caffeine
Cut back slowly. If you stop suddenly, you may trigger caffeine withdrawal symptoms. These can include:
- headaches
- tiredness
- anxiety
- difficulty concentrating
- tremors.
Drink plenty of water. Not drinking enough water can make your caffeine withdrawal symptoms worse.
Have your last coffee by early afternoon so the caffeine can work itself through your system before bedtime.
Ask for a single shot if you are buying a coffee at a café.
Switch to decaf coffee, fruit tea or herbal tea. Some people find that a cup of chamomile tea after dinner improves the quality of their sleep.
Find other ways to naturally boost your energy levels, such as:
- being physically active
- getting enough sleep
- eating well.