Undesirable substances and nutrients - interaction effects

Seafood contains many nutrients which have beneficial health effects, but may also contain contaminants which are undesired in food. The combination of these substances in seafood can affect consumer health. The mutual interaction of important nutrients and contaminants is of significance for seafood safety.

The Research Program on Seafood Safety investigates interactions between nutrients and contaminants in seafood. Humans are especially vulnerable to environmental toxicants in the foetal stage and in the first years of life. Research at NIFES aims to reveal the biological mechanisms affected in the brain and nervous system, and how this modifies behaviour in developing mice and zebra fish when exposed to toxicants typically found in seafood. The ability of seafood in general or individual nutrients found in seafood to ameliorate the neutotoxicological effects of these contaminants is of special interest.

In nature mercury is converted by bacteria into methyl mercury which accumulates in the food chain. This form is most commonly found in seafood, and it is toxic to humans. Mercury poisoning is characterised by damage to the brain and the central nervous system and can result in behavioural changes and mental disturbances. Studies at NIFES have demonstrated that selenium, found in substantial amounts in seafood, can reduce the effects of methyl mercury. The EU has maximum levels for mercury in fish and other food.  Tolerable weekly intakes (TWI) have been set by risk assessment bodies for both total mercury and methyl mercury.

Flame retardants such as polybrominated diphenylethers (PBDEs) are organic compounds which are used in a number of products to prevent fire. These compounds are magnified in the food chain and have been found in human blood and breast milk. The acute toxicicty  of these substances appears low, however there is  a need for a better understanding of the long-term effects of exposure. No TWI has been established for PBDEs or the other classes of brominated flame retardants due to the complexity of these compounds and the limited information available. Consequently the EU has not set maximum levels for   for PBDE or other flame retardants in food.

Studies performed at NIFES have shown that small doses of flame retardants  cause behavioural changes and learning difficulties in and mouse models.  To contribute in establishing maximum levels and TWI of flame retardants At present the Research Program Seafood Safety at NIFES includes studies to identify the effects of flame retardants, including PBDE, on development and behaviour in mice which are exposed to PBDE alone and in combination with fish.  

Due to the  accumulation and biomagnifications of environmental contaminants in aquatic food chains, surveillance and understanding of the biological impacts of these contaminants  has high priority in order to evaluate seafood safety.

Read more:
Facts about undesirable substances