UK Issues AdvisoryConcerning Fish Consumption
Women who are pregnant or may become pregnant,as well as children younger than 16 years of age, should avoideating shark, marlin and swordfish, advises the UK's Food StandardsAgency (FSA).
The caution was issued after routine FSAresearch found relatively high levels of mercury in these fish,according to an agency statement sent recently to the Cayman Islands'Medical Officer of Health, Dr. Kiran Kumar.
While elevated mercury levels are not necessarilyharmful, intakes above nutritional guidelines may adversely affectthe nervous system. The FSA notes that the greatest risk is tounborn babies, as high mercury levels could impair mental skillssuch as attention and memory. And, although mercury does not passinto breastmilk in large amounts, women who are breastfeedingmay also want to avoid eating shark, marlin and swordfish.
Following unborn babies, infants and childrenare at higher risk of mercury poisoning than adults because theyeat more food relative to their body sizes; an excess of the metallicelement could affect their physical co-ordination, the advisorystates. In adults, elevated mercury levels may lead to a conditioncalled paraesthesia, indicated by a creeping or tingling sensationin the skin. These effects are likely to be temporary, unlessexposure is very high.
The FSA statement was released as a precautionarymeasure until research findings have been studied in more detail,and further advice has been received from the UK Government'sCommittee on Toxicity, an independent advisory body. However,the US, Canada, Australia and New Zealand also recommend thatpregnant women limit their consumption of shark, swordfish andcertain other predatory fish eaten in these countries.
Mercury, which occurs naturally in the environment,can be released into the air through industrial pollution andeventually contaminate surface water. Bacteria in the water thenchange mercury into the more toxic form of methylmercury.
Fish absorb methylmercury from water asit passes over their gills and while feeding on aquatic organisms.The FSA advisory states that larger predator fish such as shark,marlin and swordfish are therefore exposed to higher levels ofmethylmercury as they live longer and eat a larger number of fishthemselves during their lifetimes.
While there is no local data regarding mercurylevels, Dr. Kumar recommends that persons in the high-risk groupfollow the UK advisory.