Caffeine use in the 21st Century: Considerations for Public Health
Corresponding author: Kay Rutherfurd-Markwick, School of Food and Nutrition, Massey Institute of Food Science and Technology, Massey University Albany, Private Bag 102 904, North Shore City 0745, New Zealand, Tel: +64 9 414 0800, Email: K.J.Rutherfurd@massey.ac.nz
Variability of caffeine content in different beverages and products
Caffeine levels in coffee are approximately 50-70% higher than in tea , and also vary more , with the caffeine content of coffee ranging from 60-200 mg per serving of ready-to-drink coffee, 40-180 mg/serve of filtered coffee and 30-120 mg/ serve of instant coffee . A snap-shot study of the caffeine content of a single shot espresso from 20 commercial outlets in Glasgow showed a six-fold variation in caffeine content (51- 322 mg/serving) with a four-fold variation in volume . A similar study in Australia  also found considerable variation in both espressos purchased from cafe chains in different locations 49-214 mg/serving) and coffee-flavoured milks obtained from grocery stores (33-197 mg/serving). Both sets of authors [21,22] quite rightly point out that such variation, accompanied by the lack of information about the caffeine content of drinks being served, could put individuals at increased risk of the effects of caffeine toxicity. This is particularly true as the consumer cannot rely on the volume being proportional to caffeine content, as demonstrated by espressos produced by three different sources, each contained 140 mg of caffeine, but had volumes of 26, 45 and 70 mL, respectively . Energy drinks contain varying amounts of caffeine according to brand; typically the caffeine content of 1-3 cups of coffee , and often including additional ingredients also aimed to enhance mental alertness and physical energy, such as taurine, sugars and amino acids.
Since people are likely to adapt their caffeine consumption habits according to their own personal consumption experiences (positive or negative), it is not surprising that there are associations between certain genotypes affecting caffeine metabolism and caffeine consumption habits. Individuals with the ADORA2A T/T genotype, who tend to experience negative effects following caffeine ingestion, consume significantly less caffeine than carriers of the C allele . A recent study , has identified 8 loci which are associated with caffeine consumption, most of which are in or near genes associated with the pharmacokinetics or pharmacodynamics of caffeine.
Effects of caffeine consumption and reasons for consumption
Caffeine intake now…
…and in the Future?
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