Fish-diet mothers ‘have brighter children’

by Nigel Hawkes
Health Editor 
http://www.timesonline.co.uk/
February 16, 2007

Women who eat fish during pregnancy have brighter children, 
according to a study. 

The evidence suggests that advice to expectant American 
mothers to limit fish consumption for fear of mercury poisoning 
is misguided. 

The study supports the contrary advice, given by the Food 
Standards Agency in the UK, which backs fish as a healthy food. 
The FSA simply advises mothers to avoid shark, swordfish and 
marlin, and restrict their intake of tuna. 

The new research into children’s behaviour and intelligence suggests 
that women who follow the US “advisory” issued in 2004 to limit 
consumption, or cut fish out of their diet altogether, may miss 
nutrients that the developing brain needs - and so harm their children. 

The findings come from a study of almost 9,000 British families 
taking part in the Children Of The 90s project at the University of 
Bristol. 

The lead researcher, Joseph Hibbeln of the US National Institutes 
of Health, and the Bristol scientists, including Professor Jean 
Golding, compared the amount of fish eaten by pregnant mothers 
with the development of their children up to the age of eight. 

Seafood - fish and shellfish - is the predominant dietary source 
of long-chain omega3 fatty acids, which are essential for 
development of the nervous system. 

Middle-class women are more likely to eat fish, but even after 
adjusting for social class and 27 other factors, including 
breast-feeding, the link between fish and children’s development 
held true. This suggests that fish-eating is not simply a marker 
for social class. 

Mothers who ate more seafood than the US guidelines (340 grams, 
or three portions a week) had children who were more advanced 
in development tests measuring fine motor, communication and 
social skills as toddlers, had more positive social behaviours and 
were less likely to have low verbal IQ scores at the age of eight. 
Those children whose mothers had eaten no fish were 28 per 
cent more likely to have poor communication skills at 18 months, 
35 per cent more likely to have poor fine motor coordination at 
age three and a half, 44 per cent more likely to have poor social 
behaviour at age seven and 48 per cent more likely to have a 
relatively low verbal IQ at age eight, when compared with 
children of women who ate more than the US guidelines advised. 

Dr Hibbeln said: “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 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 neuro-developmental outcomes than children of 
mothers who ate more seafood than the recommended amounts.” 

The findings are published in this week’s issue of The Lancet. 

Sue Macdonald, the education and research manager at The 
Royal College of Midwives, said: “Midwives are very aware of 
the importance of advising women and their families of the 
benefits of eating fish - including fishes high in omega - 
beneficial both for brain development of the growing baby, 
and for long-term health benefits for a healthy heart. 

“But it is also important that women are aware that they should 
avoid raw seafood - especially raw shellfish. 

“At present they should also avoid shark, marlin and swordfish 
as there has been a suggestion that this might carry higher 
levels of mercury. 

“I would advise women to talk to their midwife - who can give 
them realistic advice.” 

Harvest of the sea brings health benefits on a large scale

- Evidence that fish - especially oily fish - is good for health 
has come from many sources 

- Long-term studies in the Netherlands have shown that people 
who eat fish are less likely to develop heart disease 

- The Japanese, for whom fish form a significant part of the diet, 
have the greatest life expectancy in the world 

- Omega 3 fatty acids in fish have been linked to lowered risks 
of asthma, dementia, depression and inflammatory conditions 
such as rheumatoid arthritis 

- The only concern has been the presence of low levels of 
methyl mercury in some kinds of fish. But the only known 
cases of mercury poisoning from fish come from Japan, 
where in the 1950s and 1960s industrial pollution of the sea 
caused problems for people living in Minamata and Niigata