Coffee is, after petroleum, the second most commonly traded commodity in the world. Its popularity is related to its impact on the body's physiology; it's a potent stimulant. In the brain there is a chemical compound called adenosine which relaxes the brain and consequently the body. Caffeine binds to the adenosine receptor thus blocking this natural pathway of sedation. It also stimulates the body to release adrenaline, the "fight or flight" hormone, thus providing a potent physiological boost.
Coffee's origins are traced to Africa and its salutary properties were probably first appreciated in the Islamic world. In the 17th century it was introduced into Europe and many of the English and Dutch trading companies based their wide-ranging explorations and colonial conquests on their search for supplies of tea and coffee.
There have been many studies relating the ingestion of coffee to both health benefits and health risks. Many of these reports have been heralded by headlines in the popular press leading to further confusion on the subject.
In February 2014 a large meta-analysis, a study combining the findings of some 36 separate studies with a combined total of 1,279,804 participants and 36,352 cases of cardiovascular diseases, was published. The 36 studies were culled from a total of 2,587 studies which dealt with the connection between coffee consumption and heart disease. The meta-analysis demonstrated that moderate coffee consumption (3–5 cups per day) was associated with lower cardiovascular risk (CVD), and heavy coffee consumption (≥6 cups per day) was neither associated with a higher nor a lower risk of CVD. Once again, this study has limitations. As higher coffee consumption is generally associated with less healthy lifestyles such as a higher prevalence of cigarette smoking, less physical activity and less healthy diet, the observed association between moderate coffee consumption and less disease becomes difficult to accept. In addition, because of the observational nature of the included studies, a causal relationship, despite the large amount of observations incorporated into the analysis, cannot be established with these data alone.
It is worth remembering that when we discuss coffee and health we are discussing brewed coffee without the additives of milk, sugar or the popular iced blends that have high caloric content.
It is clear, as with so many other issues in modern medicine, that there are probably no blanket rules that apply. There are individuals who, because of sensitivity to stimulants, will find that coffee leads to increased irritability, nervousness and possibly palpitations. In others, it will prove to be a requirement to get their "motors racing" after a night's sleep. But that's biodiversity, that's what makes us all different and that's why I encourage our readers not to be overly influenced by the latest medical headlines.