Researchers have investigated the advantages of fish diet in pregnant women and published their findings in the Neurotoxicology journal.
Even while there is convincing evidence that eating fish while pregnant is beneficial, there are growing worries about pollutants like mercury in fish that may have harmful effects on the unborn child. There is a warning that pregnant women shouldn’t eat fish with high mercury levels even if it is normally advised for them. Pregnant women often cut back on their seafood intake as a result.
Concerning the study
Researchers evaluated two studies employing population samples, measurements of prenatal mercury exposure, and regular child follow-ups in the current investigation.
The pre-birth cohort of the Avon Longitudinal Project of Parents and Children (ALSPAC) study monitored pregnant women from a particular geographic area from 1990 to 1992. They also tracked their children through childhood, adolescence, and maturity. The following were used as data sources: a) self-report questionnaires that were initially completed by the mother and her partner and later by their children; b) links to medical records; c) biological sample tests; d) physical examinations; e) links to geographic sources of pollution discovered by geographic information systems (GIS).
The team took note of the subject’s gestational age at the time blood samples were taken in nearly 99.7% of pregnancies for which a blood measurement was performed. The mercury content of whole blood was calculated. The midwife took samples of the cord tissue after the baby was delivered.
The Sheffield tests were used to assess the total mercury level in the tissue of the umbilical cord using a convenience sample of kids. For the detection of about 13 elements, including magnesium, iron, manganese, zinc, and copper, the bulk of samples in phase 1 were examined using inductively coupled plasma-optical emission spectrometry (ICP-OES). Mercury and selenium concentrations were measured using atomic fluorescence methods.
In order to assess mercury concentrations using a different method, an ALSPAC umbilical cord sub-sample was examined for the Danish analysis. The samples were taken from people who at the time had both a sufficiently large cord sample and genome-wide association study (GWAS) data. After cord tissue samples were freeze-dried, mercury was found. A proxy for prenatal exposure to methylmercury was the quantity of mercury detected in the umbilical cord.
Over 11,000 pregnant women were given estimates of their diets using a food frequency questionnaire (FFQ) in the third trimester of pregnancy. The FFQ asked three questions about the pregnant women’s seafood intake, including how frequently they consumed white fish, oily fish, and shellfish. Along with information on usual portion sizes and total energy consumption, this information allowed for an estimation of the total amount of fish consumed.
The mother’s total blood mercury levels were compared to six sociodemographic variables, the pregnant woman’s reported dietary intake of 103 items, and the pregnant woman. The study’s findings revealed greater levels of mercury in first-time mothers, older women, people in higher-status employment, people with higher levels of education, and people who owned (or were buying) homes. The number of amalgam fillings in the woman’s mouth at the start of pregnancy and the number of such fillings that had been removed and replaced throughout pregnancy accounted for an extra 6.5% of the variation in the total blood mercury.
Unadjusted positive relationships between Hg and the three birth measurements were found in the research. There was a statistically significant difference between the adjusted birth weights of the children of mothers who consumed fish and those who did not. The team discovered a difference after controlling for the mother’s consumption of fish, finding that there was no correlation between Hg and birthweight if the mother ate fish. If she didn’t, there was a bad association, on the other hand.
There was a link between the maternal blood Hg level and preschoolers’ overall scores between the ages of two and four. The Denver Developmental Screening Test (DDST) and maternal blood Hg levels were compared in 20 tests, although only one revealed a meaningful correlation between the two. There were no indications that maternal Hg levels and cognition were negatively correlated.
Overall, the study’s findings showed that sophisticated cognition and reasoning abilities in the ALSPAC children of pregnant fish-eating mothers were positively correlated with the amount of Hg exposure in utero.
- Jean Golding, Caroline Taylor, Yasmin Iles-Caven, Steven Gregory, The benefits of fish intake: Results concerning prenatal mercury exposure and child outcomes from the ALSPAC prebirth cohort, NeuroToxicology, Volume 91, 2022, Pages 22-30, ISSN 0161-813X, DOI: https://doi.org/10.1016/j.neuro.2022.04.012