Fatty acid patterns of major classes of lipids of serum were measured in forty Argentine children ages 2 to 24 months admitted to the hospital with chronic malnutrition. A normal control group of 48 children from the same population was also examined. Serum lipids were extracted and separated into phospholipids, cholesteryl esters, triglycerides, and free fatty acids. These were converted to methyl esters which were analyzed by gas chromatography. In chronic malnutrition, the fatty acid patterns of phospholipids and cholesteryl esters indicated changes characteristic of essential fatty acid deficiency of moderate degree. The total omega 6 acids were found to be highly significantly diminished from normal, and the ratio of 20:3 omega 9/20:4 omega 6 was highly significantly increased. Decreased proportions of omega 6 metabolites suggested impaired desaturase activity, and elevated ratios of 22:4 omega 6/20:4 omega 6 and 20:2 omega 6/18:2 omega 6 suggested increased chain elongation in chronic malnutrition.

Pregnant rats were kept throughout gestation on a control diet (i.e., 25% protein), on a low protein diet (i.e., 5% protein) or on a fat-free diet. At 20--21 days of gestation, the rate of 9-, 6-, and 5-desaturation was measured, using microsomes from maternal and fetal livers and placenta microsomes. The effect of protein malnutrition was more evident upon delta 6-desaturase activity from maternal liver, while a less severe reduction in the activities of delta 9- and delta 5-desaturases was observed. No measurable activities of delta 5- and delta 6-desaturases were observed in fetal liver and placenta, while a low activity of delta 9-desaturase was detected in both tissues from the three groups under study. We concluded that delta 6-desaturation is greatly affected by maternal protein deprivation, and this fact could affect the normal supply of polyunsaturated fatty acids for the normal fetus growth and tissue development.

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