Pregnant women may be unknowingly harming their babies if they follow advice to reduce fish intake, according to a new study.
Published in the Lancet by researchers Joseph Hibbeln from the US National Institutes of Health and colleagues from Bristol University, the study results point out that fish is indeed not to be restricted in the diet of pregnant women.
The U.S Government and British Food Standards Agency recommend that expecting mothers should curtail amounts of fish consumption due to high levels of the heavy metal, mercury that is a well-documented contaminant of sea fish.
Fish such as the swordfish, Marlin, Tuna and shark are said to contain very high amounts of mercury due to the polluted waters in which they live.
In 2004, the U.S government and environmental regulators warned of the risks of more than 340 g of fish per week to pregnant women. Another study last year by Harvard University, cautioned against excessive fish intake as pregnant women who ate a lot of sea fish and whale blubber gave birth to children who had irreversible damage to certain brain functions.
Yet, Hibbeln and colleagues say that is just the opposite; restricted fish diet will actually lead to poor fetal brain development.
Hibbeln says that as fish contain high amounts of omega -3- fatty acids and other nutrients, cutting down on the consumption will lead to worse problems.
His conclusions stem from a study of almost 9,000 British families who took part in the Children Of The 90s project at the University of Bristol.
The scientists compared the amount of fish eaten by pregnant mothers with the development and behavior of their offspring up to the age of eight.
It was seen that mothers who ate more seafood than was considered to be safe according to US guidelines had children who were more advanced. They had higher IQs, better social skills, were more communicative and more physically accomplished.
Those children whose mothers had eaten no fish performed worse on all the same measures.
Dr Hibbeln says: "We have found that when women had low levels of seafood consumption, the outcome is exactly the opposite of what was assumed by the United States Advisory. Unfortunately, the advice appears to have had the unintended consequence of causing harm in a specific developmental domain - verbal development - where protection was originlly intended.
"We recorded no evidence to lend support to the warnings of the US advisory that pregnant women should limit their seafood consumption.
"In contrast, we noted that children of mothers who ate small amounts, 340g per week, of seafood were more likely to have sub optimum neurodevelopment outcomes than children of mothers who ate more seafood than the recommended amounts."
Gary Myers of the University of Rochester, New York, is a pediatric neurologist who has conducted his own study of fish consumption among pregnant women in the Seychelles Islands.
They consume a lot of seafood - about 12 fishmeals a week - and they had mercury levels about 10 times higher than American women. Yet Myers discovered no link between the metal and their children's cognitive test scores.
Myers feels that the oils in fish may protect against mercury's toxicity, and hence, plans further research to test this notion.