Fishing For Answers
Wed, 08/06/2008
Staff Writer
While most people concerned about potential health risks from fish focus on the mercury levels, researchers in a Tel Aviv University laboratory are seeking to determine the impact of the antibiotics in them. “Fish farmers want the highest density of fish and that means less of an area for them to swim and an increased likelihood of them developing infections,” explained Arie Nesher, director of the university’s Porter School of Environmental Studies. “To combat the infection, they are injected with a lot of antibiotics that we get into our system” when we eat the fish, he continued. “What is the impact on the body? Does it weaken the immune system? What is the amount of antibiotics that can [safely] get into our system? How much fish can a person eat before it affects him, and how long is the impact on the body?” These same concerns apply to the poultry industry, Nesher pointed out. “That’s why you see on the market antibiotics-free chickens,” he said. “In Israel, several farms have moved in this direction. Their chickens are more expensive because they raise fewer chickens and they have to make up for that in the cost.” Among the other questions his researchers are exploring is whether regulatory agencies should get involved. Should they, for instance, regulate the number of poultry or fish that can be raised per square foot? Should they regulate how much, how often and what kind of antibiotics can be injected? These questions are particularly important when it comes to infants, Nesher said. “Their formation of the immune system comes in the first half-year, so it is important what food they get,” he explained. “And women living in Europe and also in Israel are asked not to eat fish during the early stages of pregnancy because of mercury.” Many of the mercury warnings surround tuna because it is a large fish, but Nesher said the warning should apply to all fish. “A portion of the North Sea is very polluted, and some rivers in Europe are polluted,” he said. “Salmon from the North Sea that comes from Norway and Sweden cannot be imported to Europe because of the contamination. So it is cheap and is exported to other parts of the world, including Israel where it is very cheap. ... In Israel, about 50 percent of the fish are from fish farms and the rest are from the sea.” Researchers at the Porter School are also now exploring the “new frontier” of genetics in their attempt to learn what environmental conditions — such as pollutants, chemicals or even an extreme event like the Holocaust — causes a chemical reaction that results in the switching system in genes to turn on and off. Nesher said it is already known that there is a correlation between diabetes and hunger. “If a high dose of a chemical causes the system to turn off and on, it has a long-term impact on the genetic structure,” he said. “It actually changes the genes and that change is passed on to other generations. We see it in mice. This is mind-boggling because we were never aware of the impact before.” Some of the researchers are studying Holocaust survivors and their offspring. They are trying to determine whether the hunger people experienced in concentration camps had an “impact on second and third generations ... because it could have caused the genetic switch to change on or off and that could lead to diabetes.” Nesher said the biggest difficulty in carrying out this sort of basic “research is that there is little funding for it. “This is a totally new area and most scientists are working for the pharmaceutical industry because that is where the money is,” he explained. The school was created in 2000 and has 40 doctoral students working on environmental projects, along with 70 masters’ students. “The mission of our school is to have an impact on the environment in Israel on a national level and in all areas,” Nesher said. “Every resolution of the government should consider the long-term effect on the environment. You have to create academic centers to generate this knowledge to have it as a base for the decision-making process.”