Does Eating Fish Helps Improve Intelligence?

Women can get the recommended amount of DHA by eating two servings of fish, including fatty fish, per week (2). Fish are good sources of DHA because of what they eat in the wild. Farm-raised fish may not contain DHA unless they are fed foods rich in DHA.

Pregnant women should avoid fish that can be high in mercury, like shark, swordfish, king mackerel and tilefish (5). High levels of mercury can harm the baby’s developing central nervous system. Women can safely eat up to 12 ounces of fish that have small amounts of mercury (5).

These fish include wild fish that are good sources of DHA (and EPA), including salmon, herring, sardines and fresh-water trout. Women also can get DHA from albacore (white) tuna, but should limit themselves to 6 ounces or less a week because albacore tuna can contain more mercury than canned light tuna (5). Women who do not want to eat fish can look for other sources of DHA, such as fortified foods.

They also can take a daily supplement that contains at least 200 milligrams of DHA. Several prenatal vitamins contain DHA, either from fish oil or other sources. A pregnant woman, however, should always check with her health care provider before taking any supplements.

How can taking DHA during pregnancy affect infant development? Some studies suggest that babies of women with higher DHA consumption during pregnancy (from eating fish or taking supplements) may have better mental, visual, social and motor development than babies of women with lower DHA consumption (2). A Norwegian study found that 4-year-old children of women who received DHA supplements during pregnancy and lactation scored higher on tests of intelligence than babies of unsupplemented women (6).

A study in Great Britain found that women who didn’t eat any fish during pregnancy were 48 percent more likely than women who ate at least 12 ounces of fish a week to have a child with low verbal IQ scores (7). However, it is unclear whether the benefits of eating more than 12 ounces of fish a week (which exceeds the current U.S. recommendations) outweighs the potential risks of higher levels of mercury exposure. One recent study also found that children of women who took fish oil supplements during pregnancy were less likely to have developed asthma by age 16, possibly due to the effect of omega-3s on the immune system (8).

Do infants benefit from DHA after birth? Rapid brain growth continues after birth.