ST. LOUIS — Soybean oil enriched with stearidonic acid (SDA) increased the omega-3 fatty acid index in subjects participating in a study appearing on-line Aug. 25 in The American Journal of Clinical Nutrition and involving researchers from the Monsanto Co., St. Louis, and the University of South Dakota in Sioux Falls. The study identified the omega-3 fatty acid index as the sum of two omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — as a percentage of total fatty acids.

In the placebo-controlled, double-blind multicenter study, 252 overweight subjects randomly were assigned to one of three treatments for 12 weeks. A control group daily took 1 gram of encapsulated soybean oil plus 14.7 grams of liquid soybean oil. A second group daily took 1 gram of encapsulated EPA plus 14.7 grams of liquid soybean oil. A third group daily took 1 gram of encapsulated soybean oil plus 14.7 grams of soybean oil enriched with SDA. After 12 weeks, treatment values for the omega-3 fatty acid index were 4.15 plus or minus 0.12% for the control group, 4.84 plus or minus 0.13% for the EPA group and 4.69 plus or minus 0.15% for the SDA group.


The omega-3 fatty acids EPA and DHA are found in fatty fish. The body also converts the omega-3 fatty acids SDA and plant-based alphalinolenic acid (ALA) into EPA and DHA, but SDA is converted more efficiently than ALA.

Monsanto and The Solae Co., St. Louis, have collaborated to add SDA to soybean oil. The Solae Co. offers Soymega, a soybean oil enriched with SDA that has been shown to work in baked foods, soups, sauces, beverages, snack bars, dressings and yogurts.