Soybean-oil more healthful than fish-oil capsules

Nutrition Health Review, Wntr, 1989

Soybean-Oil More Healthful Than Fish-Oil Capsules

A few tablespoons of a soybean-oil-based salad dressing confer the same health benefits as fish oil capsules, a new preliminary study suggests. Omega-3 fatty acids in fish oil have become popular with consumers lately, but the health claims remain controversial.

Linolenic acid, found largely in soybean oil, is also an omega-3 type fatty acid, but its molecular structure differs from that of omega-3 fatty acids found in fish oil. For the study, conducted in Peoria, Ill., by chemist Edward A. Emken and colleagues from the United States Department of Agriculture's Agricultural Research Service, two men were fed milk shakes containing a small amount of chemically labeled linolenic acid and two were fed shakes without the acid.

Analysis of blood samples taken periodically from the four men over three days showed that within a couple of hours, the two who had ingested the linolenic acid had begun to convert it to the same type of omega-3 fatty acids found in fish oil. The researchers found that one of the two men who drank a shake with linolenic acid converted only a trace of it to omega-3 fatty acids, possibly because he had satisfied his dietary need for omega-3 fatty acids with foods he had eaten the previous week, they said.

According to Emken, salad dressings containing soybean oil have about 7 to 8 percent linolenic acid. Soybean oil in shortening and hard margarine contains about 3 per cent linolenic acid. About two tablespoons of non-hydrogenated soybean-oil-based salad dressing provides about the same amount of linolenic acid as most fish oil capsules, according to Emken, who cautioned that "people shouldn't go overboard and consume so much soybean oil that they increase their total fat intake." Research News (a publication of the U.S. Department of Agriculture).