CARDIFF, UNITED KINGDOM. An emulsion is a mixture of two immiscible (unblendable) substances. Emulsions are common in the food industry and include margarine and mayonnaise (oil-in-water emulsions). Emulsions are usually stabilized with surfactants such as lecithin. The main advantage of emulsions is improved digestibility, absorption, and palatability. British researchers completed a trial to determine if pre-emulsification of long-chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the main components of fish oils, would improve their absorbability (bioavailability).
The trial involved 14 women and 10 men who were randomized to receive a mixture of oils (either emulsified or non-emulsified) with their breakfast. The oil mixture contained 43% concentrated fish oil, 31% borage oil, and 26% flaxseed oil. The participants had blood samples drawn prior to breakfast and 1.5, 3, 4.5, 6, 7.5, and 9 hours after. Analyses of the blood samples showed that the absorption of EPA and DHA in the group receiving the non-emulsified oil was only 34% and 44% respectively of that observed for the group receiving the emulsified oil.
The experiment was repeated after a 20-day washout period (the emulsified group receiving non-emulsified oil and vice versa) with similar results. The researchers observed no difference in absorption for palmitic acid, stearic acid, oleic acid, or linoleic acid suggesting that the increased absorption observed with emulsification is limited to long-chain polyunsaturated fatty acids such as EPA and DHA. The authors conclude that pre-emulsification significantly improves the absorption of fish oils.
Garaiova, I, et al. A randomised cross-over trial in healthy adults indicating improved absorption of omega-3 fatty acids by pre-emulsification. Nutrition Journal, Vol. 6, (4) 2007