Onlooker

Green question
Fat of the land
Hippocrates remembered

Green question

Green tea, made by steaming freshly picked leaves at a high temperature to inactivate oxidising enzymes and leave the polyphenols intact, is widely consumed in Asia, and is the most popular beverage in Japan. The main constituent among the polyphenols in green tea is epigallocatechin-3-gallate, which has been shown in animal experiments to possess antimutagenic, anticarcinogenic and anti-inflammatory properties.

Epidemiological studies have shown that consuming green tea may reduce the risk to humans of chronic atrophic gastritis, gastric cancer, skin cancer, coronary arterial disease and certain microbial infections. This is one factor in the popularity of the beverage, particularly in Japan.

Gastric cancer is one condition that has shown a steady decrease in incidence since 1930 in the West. The effect attributed to decreased consumption of preserved foods and increased consumption of fresh vegetables and fruits. Yet in Japan the incidence of the condition has shown a much slower decline.

In a population-based, prospective, cohort study carried out in Japan and reported in the New England Journal of Medicine for March 1, a total of 26,311 residents completed a self-administered questionnaire that included questions about the consumption of green tea beverages. The relative gastric cancer involvement in people who drank “less than one” and those who drank “more than five” cups daily suggested that green tea did not materially either protect against gastric cancer or predispose towards it. However, heavy tobacco smoking was associated with a greater consumption of green tea, and this introduced a complication, making analysis less practicable.

In the course of the trial it also emerged that no association was evident between the risk of a person developing gastric cancer and the consumption of black tea or coffee. The possible role in cancer induction of Helicobacter pylori, which is known to be a strong risk factor, was not determined.

Fat of the land

We have a strange cult of obesity, which is difficult to understand. “Tubby” is a term of endearment, but “skinny” and “weedy” carry an aura of disparagement and suspicion. We hear of jovial fat monks and miserable underfed clerks and brigands.

Plutarch tells us of Julius Caesar's remark that “he had no fear of those fat and long haired fellows, but rather of those pale and thin ones”. Yet we hear serious concern expressed today over the widespread increase in pathological obesity in the population of affluent nations. Obesity, it appears, is one of the great menaces of our well-fed and physically lazy age.

Pathological overeating is a phenomenon where dopamine, gamma-aminobutyrate, noradrenaline, serotonin and perhaps other neurotransmitter compounds play a role in maintaining energy balance, and it has a significant psychological component which may offer a means of avoiding it. Any serious increase in energy intake through choice and quantity of food, and any reduction of energy expenditure through the adoption of habits which call for little physical exertion will encourage increase in body weight.

Family eating problems involving the consumption of fast foods and preprepared meals, and drinking of sweetened effervescent beverages have increased the likelihood of developing obesity in childhood. In addition, vastly increased reliance on motorised transport, a lack of athletic facilities in schools, and the growing habit of sedentary watching of television programmes, usually with unnecessary indulgence in snacks of fatty foods, have encouraged lifestyles where the expenditure of muscular energy is minimised.

Parental influence on both food consumption and exercise is an important factor for children in determining obesity later in life. It is noteworthy that children who partake of family meals consume more fruit and vegetables, less fatty foods, and fewer sweetened effervescent drinks than those left to their own devices. Those who habitually view much televised advertising can often be influenced to turn to foods that are, if taken regularly, unhealthy. Childhood obesity is likely to persist into adult life, when it gives rise to sickness and premature death. One cause of excess mortality from this condition is cardiovascular disease. An increase in body mass index, with a 20 per cent or greater excess of weight relative to body stature and build, is associated with atherosclerosis of the aorta and coronary arteries in individuals ages between 2 and 39 years.

The role of sweetened drinks in the rise of childhood obesity has been discussed by a group of United States scientists in the Lancet for February 17. This is an important factor and has been held responsible for an increased obesity rate among children in the US of 100 per cent between 1980 and 1994. Over that period, the consumption of soft drinks sweetened with sugar has increased enormously, resulting in a daily intake of sucrose averaging 36.2g for adolescent girls and 57.7g for boys. This is a distinctly unhealthy tendency.

Hippocrates remembered

The Hippocratic oath, which used to be taken by individuals qualifying in medicine but is now largely ignored, is taking on a new significance. During the annual meeting of the American Association for the Advancement of Science in San Francisco, a symposium was held to consider the merits of introducing an oath based on the Hippocratic model but covering all scientific disciplines.

The argument advanced by the proposers of the scheme was that such a move might help scientists to recover some of the public confidence and trust which recent developments in technology have done much to destroy. From the critics it was pointed out that scientists might be discouraged from undertaking avenues of research that might ultimately work to the benefit of society.

The move to introduce an oath for scientists was triggered in the United States by the nuclear arms race, while in Europe the stimulus has come mainly from the controversies surrounding bovine spongiform encephalopathy and genetically modified foodstuffs. French scientists are seriously looking to an oath that might make researchers more conscious of their duty to the general public. Physicists in the US doubt whether such a move would win back public trust in science, since researchers can never predict the outcome of their work or how the technologists might use it to good or evil ends.

Moreover, an oath would be difficult to enforce in practice, and scientific societies mostly would be reluctant to undertake the responsibility of a disciplinary approach. However, some pressure groups in the US are demanding that scientific researchers sign some sort of ethical pledge without delay, refusing to undertake any work which involves the design and development of weapons of mass destruction.