Enriched eggs as a source of N-3 polyunsaturated fatty acids for humans

Abstract

Dietary intake of omega-3 fatty acids (n-3 PUFA) decreases the risk of heart disease, inhibits the growth of prostate and breast cancer, delays the loss of immunological functions, and is required for normal fetal brain and visual development. The US has not established a recommended daily intake for n-3 PUFA. However, Canada has established the Canadian Recommended Nutrient Intake (CRNI) at 0.5% of energy. Dietary sources of n-3 PUFA include fish, chicken, eggs, canola oil, and soybean oil. Food consumption studies in the US indicate that the majority of Americans do not meet the CRNI for n-3 PUFA. Mean n-3 PUFA consumption was 78% of the CRNI for Midwestern women during pregnancy. In Midwestern women at risk for breast cancer, the mean n-3 PUFA consumption is approximately 50% of the CRNI. Increased consumption of n-3 PUFA requires identification of a food source that the public would eat in sufficient amounts to meet recommended intake. N-3 PUFA-enriched eggs can be produced by modifying hens diets. When 70 g/kg of cod liver oil, canola oil, or linseed oil are added to a commercial control diet, the n-3 PUFA are increased from 1.2% of egg yolk fatty acids to 6.3, 4.6, and 7.8%, respectively. Feeding flaxseed increases linolenic acid in the egg yolk about 30-fold, and docosahexaenoic acid (DHA) increases nearly fourfold. When individuals are fed four n-3 PUFA-enriched eggs a day for 4 wk, plasma total cholesterol levels and low-density lipoprotein cholesterol (LDL-C) do not increase significantly. Plasma triglycerides (TG) are decreased by addition of n-3 PUFA-enriched eggs to the diet. N-3 PUFA may influence LDL particle size, causing a shift toward a less atherogenic particle. Blood platelet aggregation is significantly decreased in participants consuming n-3 PUFA-enriched eggs. Overall results of studies to date demonstrate positive effects and no negative effects from consumption of n-3-enriched eggs. Three n-3 PUFA-enriched eggs provide approximately the same amount of n-3 PUFA as one meal with fish. It is recommended that n-3 PUFA-enriched eggs be used as one source of n-3 PUFA to increase individual consumption to meet the current Canadian recommendations.