The Evidence for the beneficial effects of coffee
In a recent Dutch study of dietary habits, with 40,011 participants and a mean follow-up of 10 years (van Dieren et al 2009). They found that “Total daily consumption of at least three cups of coffee and/or tea reduced the risk of Type 2 diabetes by approximately 42%” .
This finding was confirmed in a randomised control study published in 2011. They found no changes in glucose metabolism following coffee consumption, but saw significant improvements in fat metabolism and liver function over a 10 week period, comparing coffee consumption with non-coffee beverages. This study confirmed the “beneficial metabolic effects of long-term coffee consumption” (Wedick et al 2011). They also commented on the anti-inflammatory effects of coffee (a good therapy for aches and pains!), and the lower levels of liver damage (coffee after alcohol is a good idea!) in coffee drinkers.
Others have reported that caffeine may protect against Alzheimer’s disease. In a mouse model they found “…a surprising ability of moderate caffeine intake (the human equivalent of 500 mg caffeine or 5 cups of coffee per day) to protect against or treat Alzheimer’s disease (AD) and a therapeutic potential for caffeine against AD in humans” (Arendash GW, Cao C, 2010).
Coffee has been so much part of human culture for thousands of years, and such a social lubricant, that some have speculated that we have evolved a high tolerance to it. Humans in whom coffee improved cognitive function and physical endurance being favoured for survival (Yun et al 2007).
Arendash GW & Cao C.Caffeine and coffee as therapeutics against Alzheimer's disease. J Alzheimer’s Dis. 2010;20 Suppl 1:S117.
van Dieren, S., Uiterwaal, CSP, van der Schouw YT, van der Boer DL., Spijkerman, A., Grobbee DE., & Beulens, JWL. Coffee and tea consumption and risk of type 2 diabetes. Diabetologia, 2009, 52: 2561
Wedick, NM, Brennan, AM, Qi Sun, Q., Frank B Hu, FB., Mantzoros, CS & van Dam, RM. Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial. Nutrition Journal, 2011, 10: 93
Yun, AJ., Doux, JD., Daniel, SM. Brewing controversies: Darwinian perspective on the adaptive and maladaptive effects of caffeine and ethanol as dietary autonomic modulators. Med Hypotheses. 2007;68:31