The Food Standards Agency (FSA) has recommended maximum levels for consumption of oily fish because of potential health risks from pollutants.
It is worried that polychlorinated biphenyls (PCBs) and dioxins, which persist in the environment and accumulate particularly in fish, could be harmful to girls and women who are pregnant or breastfeeding or of child-bearing age. It has recommended they eat no more than two portions of oily fish a week, while everyone else should eat up to four.
In June 2003 the FSA asked experts to weigh up the risks and benefits of eating oily fish. Their advice is a blow to nutritionists trying to boost fish consumption in order to raise levels of omega-3, which is believed to have many positive health benefits.
John Rutherford, chief executive of the industry body Seafish, said average consumption was only a third of a portion a week so most people could increase their intake and stay within limits.