A study points out the importance of following a diet rich in white and blue fish during the first months of pregnancy. The results are different depending the types of this food. Thus, when the contribution to the diet of the mothers is based on canned tuna or shellfish, the data were lower.
A scientific team of the Institute of Global Health of Barcelona (ISGlobal) studied the relationship between the consumption of different types of fish during pregnancy and the attention capacity of children at eight years of age. The results, published in the International Journal of Epidemiology, show that a diet rich in fish during the earliest stages of pregnancy is related to beneficial effects for attention capacity at that age.
The research was carried out in 1,641 couples of mothers and children belonging to the INMA Project (Children and the Environment), a Spanish research network aimed at studying the role of pollutants during pregnancy and their effects on childhood. During the nine months of pregnancy, the mothers completed numerous questionnaires that contemplate the frequency of consumption for more than one hundred foods, among which were the different fish.
The data on the nutrition of children were also collected using the same questionnaire at the ages of one, five and eight years. In the last control they also performed a computer neuropsychological test (Attentional Network Task, ANT) aimed at assessing their attention function.
Among the results of the test, the experts focused on two responses, the number of omissions (errors that the examinee ignores in relation to the key stimulus), and the speed in response to those stimuli that were detected. Both responses are common indicators of selective and sustained attention.
According to the conclusions of the study, which follows the line of a previously published research on 5-year-old children, the consumption of fish during the first trimester of pregnancy caused an effect on the attention span of children at 8 years of age. This effect was greater in comparison to fish intake during late pregnancy or the intake by children at age five, when some of the neurodevelopment processes have already ended.
The formation of the brain takes place mainly during pregnancy, through complex biological processes such as the generation of neurons, the creation of synapses and neuronal myelination. Essential nutrients, such as polyunsaturated fatty acids (PUFAs), are critical to these processes. “Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are the main omega-3 PUFAs involved in neurological development and the main source of both is fish,” adds Júlvez.
These essential nutrients participate in the definition of the structure and function of the brain of the fetus, thus exerting a great impact on subsequent neuropsychological development. Attention is a complex behavior that every infant needs to learn, since it precedes the performance of other primary functions, such as memory. “We focus on the attention function because attention deficit hyperactivity disorders (ADHD) are common pathologies during school age,” says Jordi Sunyer , director of the ISGlobal Children’s and Environment program.
Differences between fish
The study also contemplates the differences between the several types of fish and shellfish: blue fish, white fish, canned tuna and crustaceans and molluscs. Both the sons and daughters of those women with a diet rich in several fish and those of women with diets rich only in blue fish or only in white fish showed very positive results in the attention tests. However, when the contribution of fish to the mothers’ diet was based on canned tuna or shellfish, the attention data were lower.
The role that genetics play in the metabolism of PUFAs was one of the elements analyzed in the research. “We observed differences in the effect of fish on the attention span of each child according to genetic variants known as single nucleotide polymorphisms (SNPs),” says Júlvez.
According to the results, there are SNPs that facilitate the metabolism of PUFAs, thus promoting the improvement of care, while others reduce it. Fish consumption has been shown to have a counterweight effect for those children who have SNPs that hinder the metabolism of PUFAs. Thus, for example, “children with the CC rs1260326 genotype, which has been associated with lower levels of PUFAs, obtained worse attention scores if the mothers had consumed little fish. However, if fish consumption was high, the results improved.”
Despite the promising results of this study, there is previous research that links fish consumption during pregnancy with childhood obesity, as well as with increased blood pressure. Therefore, experts insist on the need for more research on this issue, with the aim of determining exactly what species and in what quantities of fish are beneficial for fetal development.