Singh M. Essential fatty acids, DHA and human brain.
Indian J Pediatr,2005;72(3):239-242

Essential fatty acids cannot be synthesized in the body but they are required for maintenance of optimal health. There are two classes of polyunsaturated fatty acids (PUFAs)--omega-6 and omega-3.

The parent omega-6 fatty acid, linoleic acid (LA) is desaturated in the body to form arachidonic acid while parent omega-3 fatty acid alpha-linolenic acid (ALA) is desaturated by microsomal enzyme system through a series of metabolic steps to form eicosapentaenoic acid (EPA) and decosahexaenoic acid (DHA).

But there is a limited metabolic capability during early life to metabolize PUFAs to more active long-chain fatty acids. There is a critical role of EFAs and their metabolic products for maintenance of structural and functional integrity of central nervous system and retina. Most of the brain growth is completed by 5-6 years of age.

At birth brain weight is 70% of an adult, 15% brain growth occurs during infancy and remaining brain growth is completed during preschool years.

DHA is the predominant structural fatty acid in the central nervous system and retina and its availability is crucial for brain development.
It is recommended that the pregnant and nursing woman should take at least 2.6 g of omega-3 fatty acids and 100-300 mg of DHA daily to look after the needs of her fetus and suckling infant.

The follow-up studies have shown that infants of mothers supplemented with EFAs and DHA had higher mental processing scores, psychomotor development, eye-hand coordination and stereo acuity at 4 years of age.

Intake of EFAs and DHA during preschool years may also have a beneficial role in the prevention of attention deficit hyperactivity disorder (ADHD) and enhancing learning capability and academic performance.

Mothers who supplement their diet with fatty acids rich in docosahexaenoic acid (DHA) during pregnancy and lactation may be doing their children a favour in later years, say researchers in this month?s Pediatrics Journal.

Researchers in Norway examining the effects of DHA on mental development found that those children whose mothers had a higher intake of DHA during pregnancy scored higher on intelligence and achievement tests at four years of age than those whose mothers took fatty acids not containing DHA.

The researchers at the University of Oslo enrolled women during the 18th week of pregnancy in a randomized, double-blind trial and supplemented their diets with one of two different polyunsaturated fatty acids (PUFAs).

Participants received either cod liver oil (containing very-long-chain omega-3 PUFA rich in DHA and other omega-3 fatty acids) or corn oil (a long-chain omega-6 PUFA with no DHA content). They took the supplements from the point of enrollment until three months after childbirth.
Researchers then completed assessments of intelligence using the Kaufman Assessment Battery for Children (K-ABC) for 84 child subjects once they reached four years of age.

The team found that children born to mothers who had taken the cod liver oil during pregnancy and lactation scored significantly higher (approximately 4.1 points) on the Mental Processing Composite of the K-ABC test compared to children whose mothers had received corn oil.
The researchers classified these increases as significant.

Source: http://www.nutraingredients.com/news/news.asp?id=6185

Peds - Helland IB, Smith L, Saarem K, et al. Maternal supplementation with very-long-chain n-3 fatty acids during pregnancy and lactation augments childrens IQ at 4 years of age. Pediatrics 2003 Jan;111(1):39-44.

OBJECTIVES: Docosahexaenoic acid (DHA; 22:6 n-3) and arachidonic acid (AA; 20:4 n-6) are important for development of the central nervous system in mammals. There is a growth spurt in the human brain during the last trimester of pregnancy and the first postnatal months, with a large increase in the cerebral content of AA and DHA. The fetus and the newborn infant depend on maternal supply of DHA and AA.

Our hypothesis was that maternal intake of DHA during pregnancy and lactation is marginal and that high intake of this fatty acid would benefit the child. We examined the effect of supplementing pregnant and lactating women with very-long-chain n-3 polyunsaturated fatty acids (PUFAs; cod liver oil) on mental development of the children, compared with maternal supplementation with long-chain n-6 PUFAs (corn oil).

METHODS: The study was randomized and double-blinded. Pregnant women were recruited in week 18 of pregnancy to take 10 mL of cod liver oil or corn oil until 3 months after delivery. The cod liver oil contained 1183 mg/10 mL DHA, 803 mg/10 mL eicosapentaenoic acid (20:5 n-3), and a total of 2494 mg/10 mL summation operator n-3 PUFAs. The corn oil contained 4747 mg/10 mL linoleic acid (18:2 n-6) and 92 mg/10 mL alpha-linolenic acid (18:3 n-3). The amount of fat-soluble vitamins was identical in the 2 oils (117 micro g/mL vitamin A, 1 micro g/mL vitamin D, and 1.4 mg/mL dl-alpha-tocopherol).

A total of 590 pregnant women were recruited to the study, and 341 mothers took part in the study until giving birth. All infants of these women were scheduled for assessment of cognitive function at 6 and 9 months of age, and 262 complied with the request. As part of the protocol, 135 subjects from this population were invited for intelligence testing with the Kaufman Assessment Battery for Children (K-ABC) at 4 years of age. Of the 135 invited children, 90 came for assessment. Six children did not complete the examination.

The K-ABC is a measure of intelligence and achievement designed for children aged 2.5 years through 12.5 years. This multisubtest battery comprises 4 scales: Sequential Processing, Simultaneous Processing, Achievement (not used in the present study), and Nonverbal Abilities. The Sequential Processing and Simultaneous Processing scales are hypothesized to reflect the child's style of problem solving and information processing. Scores from these 2 scales are combined to form a Mental Processing Composite, which serves as the measure of intelligence in the K-ABC.

RESULTS: We received dietary information from 76 infants (41 in the cod liver oil group and 35 in the corn oil group), documenting that all of them were breastfed at 3 months of age. Children who were born to mothers who had taken cod liver oil (n = 48) during pregnancy and lactation scored higher on the Mental Processing Composite of the K-ABC at 4 years of age as compared with children whose mothers had taken corn oil (n = 36; 106.4 [7.4] vs 102.3 [11.3]).

The Mental Processing Composite score correlated significantly with head circumference at birth (r = 0.23), but no relation was found with birth weight or gestational length. The children's mental processing scores at 4 years of age correlated significantly with maternal intake of DHA and eicosapentaenoic acid during pregnancy. In a multiple regression model, maternal intake of DHA during pregnancy was the only variable of statistical significance for the children's mental processing scores at 4 years of age.

CONCLUSION: Maternal intake of very-long-chain n-3 PUFAs during pregnancy and lactation may be favorable for later mental development of children.

PMID: 12509593