What You Need to Know About Eating Fish
With concerns about mercury levels in fish -- a usually healthful food, how much fish should pregnant women eat? What other options provide the same health benefits as fish? Follow these guidelines to stay healthy.
Pregnant Women and Big Fish Risks continued...
Once mercury gets into surface water, it quickly makes its way through the aquatic food chain. In smaller organisms, there is usually an insignificant amount of mercury. But as fish get older or as bigger fish eat smaller ones, the mercury content begins to build.
Fish at the top of the food chain - pike, bass, older or large tuna, tilefish, king mackerel, shark, and swordfish - tend to have higher levels of mercury, from one to 1 million times greater than the amount in the waters, according to the EPA.
If you're eating a lot of fish, mercury accumulates in your bloodstream over time. While the body naturally gets rid of mercury, it may take a year for the levels to drop significantly. Thus, it may be present in a woman even before she becomes pregnant. This is the reason why women who are trying to become pregnant - or pregnant women -- should also avoid eating certain types of fish.
For women wanting to switch to other omega-3 sources, there are options, says Julie Redfern, RD, a registered dietitian in obstetrics at Brigham & Women's Hospital in Boston. She has counseled thousands of pregnant or soon-to-be-pregnant women.
"It's one of those questions that comes up almost every day … mercury and fish," Redfern tells WebMD. "Some women are very well-read, and they say they are not going to eat any fish. Others say, 'I love fish,' and want to know what's safe. I give them the FDA's list of safe fish. I ask them what fish they usually eat, and look for it on the list. I also talk to them about canned tuna, about the different kinds of tuna - and what's on the 'avoid' list."
Overall, she says, "I feel very comfortable reassuring them that if they keep it to the 'safe' fish -- and eat no more than two servings a week -- they'll be fine."
But, flaxseed oil, walnuts, canola oil, wheat germ, and omega-3-fortified eggs are excellent food sources for these fats. Also, a couple of new prenatal vitamins - and a 200 mg supplement - contain an algae-derived form of omega-3 fats, she adds.