Brain docosahexaenoate accretion in fetal baboons: bioequivalence of dietary alpha-linolenic and docosahexaenoic acids.
The dietary bioequivalence during the brain growth spurt of alpha-linolenic (LNA) and docosahexaenoic acids (DHA) as substrates for brain and retinal n-3 fatty acid accretion is reported for the fetal baboons, whose mothers consumed a long chain polyunsaturate-free diet with a n-6/n-3 ratio of 10:1. Pregnant baboons received i.v. doses of U-13C-labeled fatty acids (LNA or DHA), plasma was collected from mother and fetus, and fetal brain (occipital cortex), retina, and liver were analyzed at various times post-dose. Fetal brain DHA plateaued 15-35 d post-dose with 1.6% of the preformed [U-13C-]DHA dose recovered in the brain. In contrast, LNA-derived DHA accretion also plateaued but was 20-fold lower. Liver and retinal results were of the same order of magnitude, but showed evidence of peaks and decline. Conversion products to n-3 long chain polyunsaturate were observed in the maternal circulation at 1 h after administration, as was transfer of both fatty acids to the fetus. From these measurements we estimate that a dietary level of about 0.45% of energy as LNA is sufficient to meet the requirements of the growing fetal brain, whereas 0.03% of energy as DHA would suffice. These data are the first direct measurements of the bioequivalence of DHA and LNA in developing primates and imply that n-3 fatty acid requirements for the developing fetal brain can be met by attainable dietary LNA for diets low in long chain polyunsaturates.
Greiner
R C
RC
Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA.
Winter
J
J
Nathanielsz
P W
PW
Brenna
J T
JT
D000818:Animals; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D004041:Dietary Fats / Q000493:pharmacokinetics*; D004281:Docosahexaenoic Acids / Q000493:pharmacokinetics*; D005314:Embryonic and Fetal Development / Q000502:physiology; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D008099:Liver / Q000196:embryology / Q000378:metabolism; D010215:Papio; D011247:Pregnancy; D012160:Retina / Q000196:embryology / Q000378:metabolism; D013810:Therapeutic Equivalency; D017962:alpha-Linolenic Acid / Q000493:pharmacokinetics*
D004041:Dietary Fats; D005227:Fatty Acids; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids