Shapira, 2010 – Every egg may have a targeted purpose: toward a differential approach to egg according to composition and functional effect

Despite the suggested health advantages of traditionally- over industrially-produced western ‘regular’ eggs and the flexibility of egg composition, studies on the effects of egg intake refer mostly to quantity and lack qualitative information. The possibility of lending differential nutritional enhancement and functional advantages, i.e. vs. cardiovascular disease (CVD) or for perinatal health, could impact the current egg intake debate. N-3 polyunsaturated fatty acid (PUFA)/long-chain PUFA (LCPUFA) fortification of regular eggs by feeding extruded linseed (5%) yielded 3.8-fold higher total n-3 PUFA and 2.4-fold higher docosahexaenoic acid (DHA), with 3.6-fold lower n-6:n-3 PUFA ratio (p≤0.0005). This resulted in human dietary contributions of 10- 20% of the n-3 PUFA Dietary Reference Intake (DRI) and 40% for DHA. Together with antioxidants, they may be beneficial against CVD risks as associated with oxidative stress, endothelial dysfunction, dyslipidemia, and inflammatory processes, especially in diabetics. Eggs fortified via poultry feed supplementation could attain higher %DRI for pregnancy or lactation for key nutrients, i.e. DHA (≈120- 130%), vitamins A (9.0-15.2%) and E (51.6-65.3%), iodine (15.2-20.1%), and selenium (33.7-39.3%). For infants aged 1-3 years, the improvement in %DRI for vitamins, minerals, and n-3 PUFA needed during peak brain development could be even higher. Compared to increased low-density lipoprotein (LDL) oxidation as seen with intake of two regular high n-6 PUFA eggs/day, eggs with reduced n-6 PUFA (by 40%), increased n-9 monounsaturated FA (MUFA) (by 30%), reduced PUFA: MUFA ratio (by 50%), and increased antioxidants vitamin E and carotenoids (by >200%), were associated with a 30% drop in LDL oxidisability (p<0.01), back to levels seen with a low-egg diet (2-4 eggs/week). Because egg composition is highly feed-dependent and closely affects plasma nutrients and lipoprotein composition and physiological qualities, it has much potential for imparting both nutritional and functional benefits. Poultry feeding could be carefully tailored for egg modification to address specific risks and requirements in consumers, warranting further research regarding differential effects and corresponding quantitative
recommendations for egg intake, to maximise beneficial and preventative potential.