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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #69457

Title: EFFECT OF DIETARY ALPHA-LINOLENIC INTAKE ON INCORPORATION OF DOCOSAHEXAENOIC AND ARACHIDONIC ACIDS INTO PLASMA PHOSPHOLIPIDS OF TERM INFANTS

Author
item Hachey, David - Dave
item Jensen, Craig
item CHEN, HUIMING - BAYLOR COLL OF MEDICINE
item ANDERSON, ROBERT - BAYLOR COLL OF MEDICINE
item Heird, William

Submitted to: Lipids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Certain fatty acids, called docosahexaenoic acid (DHA) and arachidonic acid (AA) are important parts of the fat content of membranes, especially those of the eye and brain. These two fatty acids are present in human milk but not in infant formulas, so formula-fed babies have to make their own from substances called Alpha-linolenic and linoleic acid, delivered via the diet tin baby formulas, on three-week-old, term infants. Our study showed that three-week-old, full-term infants can convert these substances to DHA and AA. We also provided a breakdown of the rates of conversion and incorporation for three groups of three-week-old infants who had received formulas with varying percentages of fat as LNA from birth. This information should be helpful in contributing to the ongoing body of information aimed at working out an optimal balance of nutrients in baby formulas for favorable growth and development.

Technical Abstract: The fractional conversion rates of plasma phospholipid Alpha-linolenic (18:3n-3) and linoleic acids (18:2n-6) to docosahexaenoic (22:6n-3) and arachidonic acids (20:4n-6), respectively, and the fractional rates of incorporation of 22:6n-3 and 20:4n-6 into plasma phospholipids were deter- mined in 27 healthy, 3-wk-old term infants who had received formulas with ~16% of fat as 18:2n-6 and 0.4% (n=6), 1.0% (n=11) or 3.2% (n=10) as 18:3n-3 from birth. The infants were given a single dose of both (U- 13C)18:2n-6 and (U-13C)18:3n-3 with a feeding and blood samples were col- lected 8, 12 and 24 h afterward for determination of the isotopic enrich- ments of the (M+18) isotopomers of plasma phospholipid fatty acids by negative chemical ionization gas chromatography/mass spectrometry. A simple precursor/product compartmental model was used to estimate fractional rates of conversion and incorporation. All infants converted 18:3n-3 to 22:6n-3 and 18:2n-6 to 20:4n-6. Although the fractional rate of conversion of 18:3n-3 to 22:6n-3 did not differ among groups, the fractional rate of incorporation of 22:6n-3 into the plasma phospholipid fraction was greater in infants who received 3.2% vs. 0.4% or 1.0% 18:3n-3 (4.1 +/- 2.2% vs. 1.6 +/- 1.5 or 2.0 +/- 1.0% of the plasma phospholipid 22:6n-3 pool daily). The fractional rate of conversion of 18:2n-6 to 20:4n-6 was less in infants who received the 3.2% 18:3n-3 intake (0.4 +/- 0.3% of the plasma phospho- lipid 18:2n-6 pool daily vs. 1.1 +/- 0.7% and 0.8 +/- 0.5% in those who received 0.4 % and 1.0% 18:3n-3, respectively). The fractional rate of incorporation of 20:4n-6 into plasma phospholipid also was less in the 3.2% vs. the 0.4% and 1.0% 18:3n-3 groups (2.7 +/- 1.4% vs. 5.9 +/- 2.6 and 4.4 +/- 1.7%, respectively, of the plasma phospholipid 20:4n-6 pool daily).