Starbucks, which started life in 1971 in Seattle, USA, is probably the most famous name in retail coffee business. Who would have thought that 35 years later, a company which sells cups of coffee could turn into a global business capitalized at 27.6 billion dollars!

An Ethiopian goat herder has been credited with discovering the stimulant effect of coffee when he noticed his goats frolicking about after munching on coffee cherries. In the 14th century, the first commercial cultivation of coffee started in Arabia. In 2003-2004, Brazil, the world’s largest coffee producer, produced 33.6 million bags (one bag weighs 132 pounds) of coffee. Columbia (11.8 million bags) and Vietnam (10.75 million bags) ranked second and third respectively. Coffee is consumed mainly for its taste and its caffeine content. Essentially it provides no nutrition to the consumer. So, does it have any health value?

Using available information from a cohort of 125,580 multi-ethnic members of a health care plan with no known liver diseases, a group of researchers found that 330 individuals developed liver cirrhosis 16-23 years later. (Arch Intern Med 2006; 166: 1190 – 1195) The association of coffee drinking and liver cirrhosis was estimated. The analysis showed that coffee drinkers had lowered risk of having liver cirrhosis, especially liver cirrhosis secondary to alcohol consumption, and abnormal liver enzymes called transaminases. The data would support the hypothesis that there is an ingredient in coffee that protects against liver cirrhosis. Other studies looking at the influence of coffee drinking on liver enzymes have been reported. The liver enzyme called gamma glutamyl transferase (GGT) becomes elevated after alcohol ingestion. Although it is a poor marker of alcohol intake and eventual liver damage, it is widely used clinically. Several studies in Europe, Asia and North America have shown an inverse relationship between coffee consumption and abnormal levels of GGT. This inverse relationship is more prominent in heavy alcohol drinkers. Another liver enzyme called alanine aminotranferase (ALT or SGPT) is considered a more reliable marker for alcohol-induced liver cell injury than GGT. An American study looked at the effect of coffee consumption on ALT levels in individuals at high risk for liver damage. The researchers found that at risk individuals who drank two or more cups of coffee per day had half the risk of developing abnormal ALT levels. However, the study did not have information on the kind of coffee (normal or decaffeinated) drunk.

Is there a link between coffee consumption and type II diabetes? Apparently so! In an Iowa Women’s Health Study, 28,812 post-menopausal women free of diabetes and cardiovascular disease were followed up for 11 years (Arch Intern Med 2006; 166: 1311 – 1316). Women who consumed ≥ 6 cups of coffee, especially decaffeinated coffee, had a 22% lower risk of developing diabetes than those women who did not drink coffee. Clearly, the protective ingredient in the coffee is unlikely to be caffeine.

Does this mean that the more coffee you drink, the better is the health benefit effect? No definite answer to this yet. Which coffee preparation – Americano, cappuccino, espresso, macchiato, mocha, Italian roast, breakfast, latte etc? Don’t know. Brazillian, Columbian, Vietnamese, Indonesian or Malaysian coffee? My personal philosophy is drink what you like and drink in moderation.

Increased global demand for manufactured goods has necessitated a ramped up schedule of production. To this end we have resorted to increased industrialization and the adoption of shift work. Consequently, there is widespread adoption of 24-hour continuous operations in industries such as mining, manufacturing, transportation and service-type industries. The standard day-shift work (DSW) schedule has evolved to include a fixed night-shift work (NSW) schedule and an alternating day- and night-shift work (ASW) schedule. Would participation in an ASW schedule lead to more health problems for these workers?

The Japanese Ministry of Health, Labour and Welfare reported that, in 2001, 21.9% of Japanese companies had adopted 24-hour operations requiring ASW. A recent report from Japan investigated the potential deleterious influence of an alternating day- and night-shift work schedule on the development of diabetes mellitus in male steel workers (J Occup Environ Med 2006; 48: 455 – 461). A total of 3203 DSW and 2426 ASW workers were followed over a 10-year period to see if the incidence of diabetes mellitus was different between the two groups. After taking into account that the ASW group of workers had more adverse lifestyle habits, such as alcohol consumption, smoking and the absence of habitual exercise, the ASW workers still had a significantly higher risk of developing diabetes. The study found that if you were an ASW worker, you were approximately 35% more likely to develop diabetes compared to a fellow DSW worker even if you had no adverse lifestyle habits.

A 2005 Swedish study of day and shift workers in the paper and pulp industries found that shift workers with a long duration of shift work exposure have increased risk of dying from coronary heart disease, diabetes and ischaemic strokes. ASW workers have also been shown to have lipid disturbance. The risk of having a low level of HDL-cholesterol (the ‘good’ cholesterol) was doubled in shift workers and high levels of triglycerides were also associated with working shifts. Shift work also exerts an adverse influence on pregnancy outcome in terms of miscarriage, low birth weight and pre-term birth. A Chinese study showed that the risk of preterm birth and low birth weight is doubled in female shift workers.

Shift workers are likely to suffer from sleep problems, lifestyle problems and increased stress. Sleep problems can cause sleep deficit and can lead to disturbed circadian rhythm. A recent news article here on ‘A good night’s sleep’ has alluded to how lack of sleep can affect your health. The increased incidence of elevated triglyceride level, depressed level of the ‘good’ cholesterol and obesity among shift workers suggests that shift work may be associated with the metabolic syndrome. This syndrome is seen as a major health problem that will impact heavily on societal health care cost. A brief article on the syndrome can be viewed here.

The requirement for ASW workers in our society is unlikely to disappear anytime soon. For some people, apart from shift work, there may be no alternative if they want to be gainfully employed. For these individuals, they should at least be informed of what ASW can do to their health and adopt some lifestyle changes to obviate some of these health hazards.