A nutrition expert explains the many benefits for pregnant and breastfeeding women, and young children, in eating fish low in mercury levels.
MANHATTAN, Kan. — For most people, eating fish and shellfish is not a health concern, according to the U.S. Environmental Protection Agency (EPA). In fact, fish contains omega-3 fatty acids and healthy oils, some of which can’t be found in any other food source. Fish and seafood also are sources of lean protein, low in saturated fat and high in essential minerals, such as iron.
Despite the numerous health benefits of consuming fish, many women have limited or avoided eating fish during pregnancy or feeding it to their young children, because of their concerns over high mercury levels that may harm an unborn baby or young child's developing nervous system.
But, these women should know that not all fish are a problem where mercury is concerned.
A recent draft report by the EPA and U.S. Food and Drug Administration (FDA) advises pregnant and breastfeeding women, those who might become pregnant, and young children to eat more fish of types that are lower in mercury to gain important developmental and health benefits. Previously, the FDA and EPA recommended maximum amounts of fish that these groups should consume, but did not promote a minimum amount.
The new minimum amount recommended is 8 to 12 ounces, or two to three servings per week, of a variety of fish that is lower in mercury. These fish include shrimp, pollock, salmon, light canned tuna (not white or albacore, which contain higher mercury levels), tilapia, catfish and cod, as examples.
The minimum recommendation comes after an FDA analysis of seafood consumption data from more than 1,000 pregnant U.S. women found that 21 percent of them ate no fish in the previous month, and those who did ate far less than the Dietary Guidelines for Americans recommends, with 50 percent eating fewer than 2 ounces a week and 75 percent eating fewer than 4 ounces a week.
“I think the message we want to get out to people is eating fish is extremely good for us no matter what stage or phase we are in life, but especially for those who are pregnant and breastfeeding,” said Sandy Procter, nutrition specialist for K-State Research and Extension and a registered dietitian. “There are only a few types of fish that we know are consistently high in mercury, and especially for people in our area of the country, those are easy to avoid.”
The fish with higher levels of mercury include four main types, she said: tilefish from the Gulf of Mexico, shark, swordfish and king mackerel. Also, pregnant and breastfeeding women should limit their consumption of white or albacore tuna to 6 ounces per individual per week, which is about the size of a can or packet of tuna eaten entirely by one person.
A focus on iron
The phrase “eating for two” is common when referencing a pregnant woman who is also eating to support her unborn child. Procter said pregnant women aren’t eating for two people calorie-wise, but they are eating with another person’s well-being in mind. Their dietary decisions affect their unborn baby.
Nutritional concerns are elevated by the fact that nearly half of the pregnancies in the United States are unplanned, according to the Centers for Disease Control and Prevention. Procter said many important nutrient needs for the woman and baby, such as folic acid, occur before a woman may realize she is pregnant.
In addition to healthful fats, Procter said fish and seafood also provide pregnant and breastfeeding women with iron—an essential mineral that helps with transferring oxygen to muscles, supporting a person’s metabolism, and growing and developing, according to the National Institutes of Health (NIH).
Dietary iron has two main forms, heme and nonheme, according to the NIH. The richest sources of heme iron are lean meat and seafood, while nonheme sources include nuts, beans, vegetables and fortified grains.
Procter said it is considered unlikely or impossible for pregnant women to get as much iron as they need from diet alone, which is why healthcare providers routinely recommend they take an iron supplement.
“Iron is a nutrient that, worldwide, women are routinely short on anyway,” she said. “Pregnancy puts an even increased demand on women for iron, especially in the third trimester.”
Infants and young children must also have adequate amounts of iron. If mothers aren’t breastfeeding, iron-fortified formulas are typically recommended for their babies. According to the NIH, the iron in breast milk alone is not enough to meet the increasing iron needs of infants older than 4 to 6 months, so mothers should make sure as babies grow, they are introduced to iron-fortified cereals and solid foods rich in iron.
Ideas for preparation
When consuming fish for the healthy oils, protein and variety of other nutrients, does it make a difference from a nutritional standpoint if it is fresh, frozen, canned or in another shelf-stable form? Procter said it is a matter of personal preference, as all forms have great nutritional value.
Even starting from a frozen state, Procter said fish thaws and cooks quickly.
“It can be easily prepared,” she said. “It can be steamed, grilled, broiled or poached. You can include it in tacos or part of a casserole. It also doesn’t heat up the kitchen, so it’s a nice food for summer.”
The FDA advises that pregnant women and young children avoid raw fish and only eat foods with fish, meat, poultry or eggs that have been cooked to safe temperatures to protect against microbes, which are harder to fight with the likely lower immune systems these women and children have.
Also, the agency advises pregnant and breastfeeding women to eat the recommended 8 to 12 ounces per week, but stay within the recommended calorie limits. Children’s portion sizes should be smaller than adult portions.
For more information about the recommendations for fish consumption, log on to the FDA’s website. For more information about nutrition for families, visit your local extension office or log on to the K-State Research and Extension website.