Role of DHA in Proper Gestation and in Development of Good Intellectual & Visual Acuity of Fetus

Introduction:

The n-3 and n-6 families of fatty acids are essential because they cannot be synthesized in the body, but must be obtained in the diet. Fatty acids are contained in the membranes of every cell in your body, but the essential fatty acids are particularly concentrated in the membranes of brain cells, heart cells, retinal cells and immune-system cells.

Research over the decades has shown that the best fatty acids for the human body are the polyunsaturated fatty acids also called the n-3 fatty acids. These n-3 fatty acids break down to form EPA (Eicosapentanoic acid) and DHA (Docosahexanoic acid). These two fatty acids i.e. EPA and DHA are called as essential fatty acids or EFA’s.

Although DHA can be obtained from alpha-linolenic acid, (ALA) the capacity for doing so declines with age. Alpha-linolenic acid is broken down to form Eicosapentanoic acid, Docosahexanoic acid and ultimately results in the formation of eicosanoids. Moreover the Synapse xt primary source of DHA i.e. alpha-linolenic acid cannot be synthesized in the body and has to be obtained from diet. In fact the body’s ability to break down the n-3 fatty acids to form EPA (Eicosapentanoic acid) and DHA (Docosahexanoic acid) declines and comes to a stop the moment the baby is born. So the older you are (beyond infancy), the less DHA you have and more the need for supplementation.
DHA in the brain and retina:

Most of the dry weight of the brain is lipid (fat) because brain activity depends greatly upon the functions provided by lipid membranes. Compared to other body tissues, brain content of DHA and arachidonic acid is very high. DHA is particularly concentrated in membranes that are functionally active, namely in synapses and in the retina.

Fatty acid in phosphatidylethanolamine of human gray matter cell membrane is roughly 25% DHA, 25% stearic acid, 14% arachidonic and 12% oleic acid. In the outer segments of retina photoreceptors of the eye more than 50% of the fatty acid content is DHA. It is DHA’s special properties of permeability and perhaps fluidity that probably accounts for this high concentration.1

DHA accrues rapidly in the prenatal human brain during the third trimester and the early postnatal period when the rate of brain growth is maximal and most vulnerable to nutritional deficiencies. Postnatal deficiencies of DHA have specifically been found to relate negatively to visual acuity, neurodevelopment, and behavior. In general, breast milk contains sufficient amounts of long chain PUFAs, including DHA, to meet these needs, assuming the maternal diet is adequate. A study examining breast milk and DHA content in Pakistani mothers versus Dutch mothers found significantly lower amounts of DHA which were directly correlated to the decreased amount of fish eaten in North Pakistan. 2
DHA in gestation:

DHA has been seen to have an important role in the maintenance of proper gestation and in the reduction of preterm births. Evidence from human and animal studies indicates that essential fatty acids of the n-3 and n-6 series, and their eicosanoid metabolites, play important roles in gestational duration and parturition, n-3 fatty acids intake during pregnancy may be inadequate. It is also documented that supplementation with long chian n-3 fatty acids such docosahexaenoic acid may be useful in prolonging the duration of gestation in some high risk pregnancies. 3
DHA in preterm labour and birth:

Preterm births are the most common cause of low infant birth weight and infant morbidity and mortality. In the absence of infections, preterm birth is characterized by lower reproductive tissue PG production and decreased inducible cyclo-oxygenase expression. Women who deliver prematurely have increased pools of n-6 fatty acid and decreased n-3 fatty acids, despite the lower PG production. Several human pregnancy supplementation trails with n-3 fatty acids have shown a significant reduction in the incidence of premature delivery and increased birth weight associated with increased gestational duration. Supplementation with long chain n-3 fatty acids such as docosahexaenoic acid may be useful in prolonging the duration of gestation in some high-risk pregnancies. 4

In preterm infants, positive relations were observed between the amount of DHA in umbilical artery phospholipids and birth weight, head circumference, and birth length.

In addition, the essential PUFA status at birth appeared to be the strongest determinant of the essential PUFA status as the expected date of delivery. 5 therefore, a higher DHA status may benefit preterm neonates, not only in terms of their intrauterine development but also in terms of their postnatal development.

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