03.When to watch your intake
For most healthy adults, a moderate intake of caffeine (the definition of which varies from source to source, but 300-400mg is commonly cited) won’t pose a problem. However, limiting or ending your caffeine intake may be warranted if:
- You’re pregnant. Studies showing a relationship between caffeine intake in pregnant women and its effects on the foetus including reduced birth weight, pre-term birth or stillbirth have resulted in the recommendation that pregnant women limit their daily consumption to 200mg per day.
- You’re young. Caffeine increases anxiety levels in children at doses of 95mg and can disrupt sleep patterns, and what is a moderate to high dose of caffeine for children and adolescents (100-400mg) can see them become increasingly nervous, jittery and fidgety. Energy drinks have been a particular source of public concern because of their high caffeine content combined with their edgy marketing that has obvious teen appeal. Some products, including V Double Hit, Wicked, Monster Energy and Mother, contain as much caffeine in a single 500mL can as two cups of instant coffee - a level that can cause unwelcome side effects in this age group.
- You’re taking certain medications or supplements. Some medications and herbal supplements may interact with caffeine. The stimulatory effects of caffeine may increase when taking the antibiotic Ciprofloxacin, for example. And the combination of caffeine and fellow stimulant bitter orange, found in a number of weight loss and sports supplements, can increase your blood pressure.
- You’re a heavy caffeine consumer. Heavy daily caffeine intake — more than 600 mg a day — can lead to some unpleasant effects including insomnia, nervousness, restlessness, irritability, stomach upset, fast heartbeat and muscle tremors. People with a 10-cup a day coffee habit undoubtedly fall into this category. But you may be unwittingly consuming this amount of caffeine from as little as two coffees, depending on how and where the coffee is made (see Coffee culture), so bear this in mind when you’re ordering another brew.
- You’re sleep deprived. Caffeine can interfere with much-needed sleep by making it harder to nod off and shortening the time you do sleep. If you then drink caffeinated beverages during the day because you have trouble staying awake it can create a cycle of poor sleep.
- Even a little makes you jittery. Some people are more sensitive to caffeine than others. If you're susceptible to the effects of caffeine, just small amounts — even one cup of coffee or tea — may prompt unwanted effects, such as restlessness and sleep problems. People who don't regularly drink caffeine tend to be more sensitive to its negative effects. Other factors that can determine how you react to caffeine include body mass, age, medication use and health conditions such as anxiety disorders.
Australians love coffee. More than one billion cups of the stuff are consumed in cafes, restaurants and other outlets each year – an increase of 65% over the last 10 years. If you’re buying your preferred brew from coffee chains and cafes and trying to monitor your daily intake, it’s worth noting that a study conducted by the University of Glasgow found caffeine levels in a single espresso ranged from 51mg to a whopping 322mg across 20 different coffee chains and cafes.