In Aotearoa New Zealand the recommended maximum daily caffeine intake is no more than 400 mg per day from all food and drink sources. People react to caffeine in different ways and the amount of caffeine that is appropriate for you will depend on your individual body size and metabolism.
Black tea and coffee can benefit health because of properties they contain such as antioxidants. However, they both contain caffeine and tea contains tannins, which lower the amount of iron absorbed by your gut. For this reason, the Ministry of Health recommends drinking only moderate amounts of tea and coffee.
Image credit: MOH, Eating and Activity Guidelines for Adults, 2020
The caffeine content in coffee can vary considerably depending on:
- the type of coffee, eg, brewed coffee may contain anywhere from 95 to 200 mg per cup and instant coffee may contain anywhere from 27 to 173 mg per cup
- the type of beans, eg, robusta coffee beans may contain twice as much caffeine as arabica
- the amount of coffee/beans used in the brewing process
- the number of shots in coffee.
For tea, the amount of caffeine depends on how much water it's brewed in, how long it's brewed for and the quality of the tea.
Caffeine for people who are pregnant or breastfeeding and for children and athletes
Pregnancy: It takes longer for caffeine to clear from your blood when you're pregnant. It's recommended to limit caffeine intake to below 200 mg per day during pregnancy and to avoid energy drinks and energy shots. Having large amounts of caffeine during pregnancy may increase the risk of miscarriage, stillbirth and having a baby with low birthweight.
Breastfeeding: Caffeine is transferred to breast milk. Some babies may be sensitive and a large amount can cause your baby to be stimulated or have poor sleep. If you're breastfeeding it’s recommended you limit your caffeine intake to less than 200 mg a day and avoid energy drinks and energy shots.
Children: Tamariki don't need caffeine from tea, coffee, cola drinks or energy drinks. It's been linked to irritability and can affect their sleep. There is research showing increased anxiety in children who consume about 3 mg of caffeine per kilogram of bodyweight per day. To put that in real life terms, 3 mg of caffeine per kilogram for a child weighing 25 kg would be 75 mg, and a 250 mL energy drink contains 80 mg.
Athletes: Some studies suggest consuming caffeine before exercising can help to improve performance and focus for some athletes. As a result, caffeine is becoming popular in sport with many different supplements and sports products available. It's important to consult with your healthcare provider before taking any form of caffeine supplement to make sure it's safe and suitable and the risk of side effects is minimised. The maximum limit of 400 mg of caffeine per day should still be followed.