The study is the first to establish a link between maternal supplementation with docosahexaenoic acid (DHA), an omega-3 essential polyunsaturated fatty acid, and enhanced foetal iron metabolism.
Researchers think DHA helps to increase the expression of certain genes that regulate iron’s transport through the placenta.
DHA may also improve iron reserves before birth and help prevent future postnatal deficiencies that could cause damage to the baby's cognitive development.
According to the World Health Organisation (WHO) anaemia affects 40–50% of vulnerable women and their infants. Studies have shown mothers on low fish and seafood intakes and a high use of vegetable oils rich in omega-6 fatty acids (FA) are at risk of inadequate omega-3 FA intake.
One study found both iron and omega-3 FA are essential nutrients for normal foetus development and the foetus depends on maternal transfer during prenatal development.
Scientists from the University of Granada and King's College London enrolled 110 healthy pregnant mothers in a double-blind, controlled and randomised trial, lasting from 28th week of gestation to delivery.
Mothers were randomly assigned to one of two groups: a control group given 400 ml/day (in two doses of 200 ml) of the control dairy drink or a fish oil-supplemented group given 400 ml/day (in two doses of 200 ml) of fish oil-enriched dairy drink. Fish oil from tuna was used as the source of DHA.
Maternal dietary intake was assessed using a 110-item food frequency questionnaire along with a 72-hour diet record. Based on this information, a recommended diet was created, where contents were exchangeable within every group of nutrients for both groups.
The results showed a beneficial effect of maternal DHA supplements on iron homeostasis through the syncytiotrophoblast, the tissue covering of the highly vascular embryonic placental region, which invades the wall of the uterus to establish nutrient circulation between the embryo and the mother.
“DHA supplementation is postulated as a nutritional strategy that not only helps in the cognitive and visual development of the baby, but also could help in preventing the risk of suffering anaemia,” said Javier Díaz Castro and Julio José Ochoa Herrera, researchers from the UGR department of physiology and lead authors of this work.
“In this regard, this maternal supplementation could prevent anaemia-related perinatal complications such as low birth weight and late cognitive development."
Two of the key nutrients in gestation and early development, iron and DHA, are known to play important roles in neuronal development of the newborn child.
Explaining omega-3’s effect
The researchers believed the key to understanding DHA’s beneficial effects on iron uptake and transport in the placenta was to look at how key proteins behaved around each other.
The proteins that made up the nutrient transport system worked in a responsive and regulatory way to keep iron homeostasis constant in mammal metabolism.
“Given the importance of these regulatory proteins in the Fe homeostasis and as previously commented, it is necessary to clarify factors and interactions that could modify their expression,” noted the researchers.
Iron deficiency in children is associated with lower levels of DHA in the red blood cells. In animal models, moderate iron deficiency during gestation and lactation resulted in changes in the fatty acid composition of the brain, liver and red blood cells of the offspring.
However, the most striking changes were in brain PUFA composition, where total (omega-3) PUFA were significantly enriched by approximately 20%, in which the DHA content is mainly responsible for this increase.
“This altered FA profile may be part of different neuronal Fe dependent biochemical pathways that are altered by perinatal Fe deficiency, which may have a lasting impact on neonatal development,” the researchers said.
Source: Journal of Functional Foods
Published online ahead of print, doi:10.1016/j.jff.2015.09.051
“DHA supplementation: A nutritional strategy to improve prenatal Fe homeostasis and prevent birth outcomes related with Fe-deficiency.”
Authors: Javier Diaz-Castro et al.