Food study highlights the need for moderation

PUBLISHED : Thursday, 17 April, 2008, 12:00am
UPDATED : Thursday, 17 April, 2008, 12:00am

Despite all that we owe to science and technology in improving the quality of life, food safety remains an abiding concern. The world has yet to reconcile rapid economic development and competitive exploitation of natural resources with contamination of our food chain by the by-product of pollution.

An example of this concern is to be found in the recent international controversy over the safety of mainland exports, including food. Hong Kong authorities have tightened the inspection and sourcing of fresh produce from the mainland after several scares in recent years over chemical contamination. If a reminder was needed that we cannot afford to relax our vigilance, it came in a report last year from the Guangdong Provincial Oceanic and Fishery Administration about rising pollution of our ocean waters by sewage, oil and heavy metals, including lead, arsenic and mercury.

It is therefore reassuring that a study of one of our fresh-food staples - fish - for mercury content has found little cause for alarm. As we report today, the Centre for Food Safety tested 266 samples of whole fish and 14 of canned fish of 89 species in the local market. Only three samples were above the legal limits for total mercury and an organic form - methylmercury - linked to possible effects on the nervous system, particularly in unborn babies.

That said, the centre sounded a wise note of caution for a high-fish-diet society, citing international standards for tolerable weekly intake of methylmercury and a 2004 study of secondary school students' dietary exposure to mercury.

Because the amounts of methylmercury relative to total mercury varied considerably in different fish species, the centre could not rule out a possible health risk to secondary school students who eat a lot of fish.

To avoid it, the centre recommends moderate consumption of a variety of fish as part of a balanced diet. Even though fish remains a prime source of many essential nutrients, such as omega-3 fatty acids and high-quality proteins, the saying 'moderation in all things' is sound advice.