Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Fish is not always "brain food" - eating methylmercury contaminated fish causes problems in adults


Warnings about methylmercury contaminated fish are not just for young children and expectant mothers, according to new research published today in Environmental Health: A Global Access Science Source. Adults who regularly eat contaminated fish could find that their concentration, dexterity and verbal memory are impaired.

The major source of methylmercury is diet, particularly large fish like shark and swordfish. The authors of this new research concluded: "methylmercury exposure at levels often encountered by adults in North America may be inducing adverse effects on neurobehavioral performance."

Methylmercury damages or destroys nerve tissue. It affects the visual cortex and the cerebellum, the part of the brain responsible for controlling complex movements and maintaining balance. This new research challenges the assumption that adults are much less sensitive to its toxic effects than children.

Ellen Silbergeld, of John Hopkins University, and her colleagues conducted the first major study on the effects of long-term exposure to small amounts of methylmercury in adults using sensitive neuropsychological tests.

The team, which included researchers from The University of Rio de Janeiro and the University of Maryland, studied a group of 129 men and women living in fishing communities of the Pantanal region of Brazil. They took samples of recent hair growth and analysed them for mercury. Because hair grows constantly, these values reflect the exposure of individuals to methylmercury within the previous three months. About one out of four of the participants were found to have mercury levels that exceeded the ’safe’ level set by the World Health Organization (WHO) for women and children. WHO will decide next week whether the current exposure limit should be decreased.

The researchers also used a number of tests to assess mental functions such as learning, attention, memory, accuracy, manual speed and dexterity. Those individuals with higher levels of mercury in their hair fared worse on the tests for motor skills, memory and concentration.

Mercury is used in small-scale gold-mining. A gold-rush began in the Patanal region of Brazil in the early 1980’s, leading to an increased concentration of mercury in the environment in the mid-1980’s. Once mercury gets into the water system, it is converted to methylmercury by bacteria found in sediment. Fish ingest it as they feed, and the concentration increases up the food chain. Larger fish species with long life-spans will contain much higher levels of methylmercury.

Methyl mercury levels are a global concern, with the major source of exposure being fish consumption. Women who have eaten grossly contaminated fish may give birth to children with severe disabilities including cerebral palsy and mental retardation. The United States Food and Drug Administration issued an advisory in 2001, warning women who were pregnant or of child-bearing age to restrict their intake of shark, swordfish, king mackerel and tilefish. Governmental advisories in the United Kingdom and other countries also warn that the diet of children should not include contaminated fish species.

This study suggests that this advice should now be extended to everyone, although the effects seen in adults are less severe than in children exposed to methylmercury before birth.

Grace Baynes | BioMed Central
Further information:

More articles from Health and Medicine:

nachricht NIH scientists describe potential antibody treatment for multidrug-resistant K. pneumoniae
14.03.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht Researchers identify key step in viral replication
13.03.2018 | University of Pittsburgh Schools of the Health Sciences

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>