Coffea Arabica, the humble Arabica coffee plant, produces 75-80% of the worlds consumable coffee and is largely responsible for the centuries-old cross-cultural phenomenon. Even today, it soldiers on thanklessly as the one acceptable excuse to procrastinate of an office-bound morning and, for some, is a major determinant of our mid-morning demeanour.
No dietary staple compares to coffee’s capacity for world-wide consumption. In terms of beverages, it continues to hold second place for consumption (after water) with approximately 500 billion cups consumed annually [1] – a number still set to rise.
But when does a daily coffee craving befall an espresso obsession? According to the decade-old research, the safe limit for a healthy adult is 400-450mg of caffeine per day (roughly four to five coffee shots).[2] Acknowledging the unnecessary risks associated with excessive intake, new research investigates the plethora of benefits still attributed to low to moderate intake.
It’s time for a fresh new look at the more recent scientific findings, and a robusta justification for your waking up to another cup of brewed ambrosia tomorrow.
1. Improve Mental Performance
Numerous studies have investigated the effects of caffeine consumption on subjects’ performance in cognitive tasks which essentially assess their mental accuracy and stamina. A range of these seemingly obscure tests have convincingly shown that attention and alertness, [3] mental fatigue, working memory and reaction time,[4] and efficiency when switching between tasks [5] are all improved with moderate intake (40-150mg or less than 2 cups) of caffeine.
Recent research is now looking at novel and naturally-occurring glutamates (caffeine-like compounds), some of which accompany caffeine in exotic teas. One compound, gamma-glutamylethylamide (GG), appears to work synergistically with moderate dosages of caffeine and further enhances its positive cognitive effects. [4, 5] Combinations of GG and caffeine have recently emerged onto the supplement market as focus-aids under the proprietary name “theaffeine”.
2. Enhance Athletic Performance
Caffeine supplementation has long been realised for its ergogenic (performance-enhancing) potential irrespective of when it’s consumed during training.[6] It has now been shown to improve athletic endurance in hot environments (up to 35 deg C).[7] More recently, significant effects have been seen to persist even in a muscle-depleted state of low glycogen (carbohydrate) storage,[8] which may provide some explanation for its efficacy (note: not safety) as a workout-enhancer in carb-starved dieters.
Finally, contrary to the dogma of ergogenic caffeine use, supplement-style caffeine consumption has been shown to exhibit its performance-enhancing effects even in regular coffee drinkers. In this study, four days of controlled caffeine supplementation did not reduce the performance-enhancing effect of caffeine, even when compared to those who had washed out (or “cycled off”) of caffeine for four days.[9]
3. Reduce Type-2 Diabetes Risk
A modern cross-sectional study of large populations of people, including 9473 cases of type-2 diabetes (T2D), found that daily caffeine consumption decreased the relative risk of developing the disease.[10] Another study (perhaps over-ambitiously) attributed an additional seven percent decline in T2D risk for each cup consumed per day.[11] But if you’re busy dividing 100% by 7%, don’t bother (it’s 14.3 – and ain’t nobody got time for that).
However, coffee-devotees indulging beyond four to six cups per day may still be be reaping additional rewards. The same systematic review of population data found that even the seemingly coffee-addicted, drinking a coffee roughly every hour of the working day, had a lower risk of type-2 diabetes compared with those who only drank one to two cups per day. Interestingly, this seems to be an effect independent of the caffeine itself (i.e. even six cups of decaf did the trick). Rather, the effect may actually be attributed to something else pressed out of the coffee bean or, alternatively, something unique that only coffee drinkers do (like work better and train harder).
Final thought
Moderate coffee consumption has been associated with numerous additional health benefits including a reduced risk of developing Alzheimer’s or Parkinson’s disease, depression and some cancers[12] (including some skin cancers). However, the data available isn’t entirely clear on what causes these benefits specifically. Furthermore, an excessive intake tempts the likes of increased stroke, hypertension, cardiac arrhythmia and osteoporosis.
With most of the benefits of coffee consumption being reached in the range of one to two cups per day and most of the associated negative risks developing after five to six cups, perhaps a daily indulgence (or two) will still get you hitting the proverbial sweet spot.
- Clarke, R.J., Vitzthum, O.G., Coffee: Recent Developments. 2001: Blackwell Science, Berlin.
- Nawrot, P., et al., Effects of caffeine on human health. Food Addit Contam, 2003. 20(1): p. 1-30.
- Foxe, J.J., et al., Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task. Neuropharmacology, 2012. 62(7): p. 2320-7.
- Haskell, C.F., et al., The effects of L-theanine, caffeine and their combination on cognition and mood. Biol Psychol, 2008. 77(2): p. 113-22.
- Einother, S.J., et al., L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite, 2010. 54(2): p. 406-9.
- Cox, G.R., et al., Effect of different protocols of caffeine intake on metabolism and endurance performance. J Appl Physiol, 2002. 93(3): p. 990-9.
- Pitchford, N.W., et al., Effect of caffeine on cycling time-trial performance in the heat. J Sci Med Sport, 2013.
- Lane, S.C., et al., Caffeine ingestion and cycling power output in a low or normal muscle glycogen state. Med Sci Sports Exerc, 2013. 45(8): p. 1577-84.
- Irwin, C., et al., Caffeine withdrawal and high-intensity endurance cycling performance. J Sports Sci, 2011. 29(5): p. 509-15.
- Muley, A., P. Muley, and M. Shah, Coffee to reduce risk of type 2 diabetes?: a systematic review. Curr Diabetes Rev, 2012. 8(3): p. 162-8.
- Huxley, R., et al., Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med, 2009. 169(22): p. 2053-63.
- Butt, M.S. and M.T. Sultan, Coffee and its consumption: benefits and risks. Crit Rev Food Sci Nutr, 2011. 51(4): p. 363-73.