The perennial question about which came first, the chicken or the egg has been debated for a very long time. The more relevant questions about chickens and eggs—especially as they relate to health and nutrition—pertain to the cholesterol content in eggs. Researchers in Israel recently completed part of an ongoing, multifaceted study of eggs, the most recent arm of which examined how the cholesterol content of eggs can be manipulated to impact health. Their takeaway message was simple: not all eggs are created equal.
 
Along with her colleagues, Niva Shapira, PhD, of the Institute for Nutrition Research, Rabin Center, at Beilinson Hospital in Petach-Tikva, Israel, traced the origins of egg cholesterol back to the feed egg-laying chickens consumed. The team then designed wheat, barley and milo-based chicken feeds that were high in antioxidants and lower in omega 6 fatty acids.
 
The custom-formulated feed was fed to young hens that had not yet accumulated omega 6 fatty acids in their tissues. The composition of their resulting eggs was then tested and the levels of nutrients in the feed were continually adjusted until a desired composition of low omega 6 and high antioxidant eggs was achieved. Dr. Shapira said the modifications made to the feed were at the grain composition level. The total amount of oils and fat were tinkered with, and the fat was changed from soy/corn to canola.
 
Two of the feed-influenced eggs were then given to study participants to eat daily. A second group of participants ate two grocery store eggs with high omega 6 levels per day. A third control group ate two to four standard grocery store eggs.

After testing the participants in each group, the Israeli researchers confirmed that the grocery store eggs contributed to a 40% increase in LDL (“bad”) cholesterol levels. In comparison, the participants who consumed two of the specialty feed-influenced, higher antioxidant eggs per day returned LDL oxidation levels similar to the control group who ate two to four eggs a week.

Dr. Shapira explained that eggs high in omega 6 fatty acids heighten cholesterol’s tendency to oxidize, which contributes to the formation of dangerous arterial plaque. “We know that the combination of polyunsaturated fatty acid, especially n-6 like linoleic acid, is very prone to oxidation and LDL oxidation is a risk factor for atherosclerosis,” she said.
 
She went on to add that the most surprising aspect of her research was when she and her team realized the big results that can come after small adjustments to their feed formula. “The unbelievable effect of small change on big response in such a critical factor: the yolk has only 5 grams of fat, the n-6 decreased from 22% to 12-15%, meaning hardly 1-1.5 grams linoleic acid change in two eggs, and a reduction of 37% in LDL oxidation,” she said “This shows how powerful small changes in food composition can be to our health.”
 
Looking ahead, Dr. Shapira said her future research will hinge on the role of eggs versus a variety of disease risks and metabolic states, as affected by different composition. “The unique capacity of egg to concentrate and transform critical nutrients—some of which may be deficient in our diet—make the eggs a ‘strategic’ food with potential for contributing to balance insufficient populations,” she commented, pointing out how eggs could impact critical developmental periods such as peri-natal, pre-conception, during pregnancy and up to ages 2-4 years old. “Eggs are among the best value for money protein and basic food, more sustainable and friendly with the environment, and easier to adapt to climate change and to acquire the knowledge of production in new populations.”
 
The team’s current study, titled “Egg modifications vs. disease risk: the effect depends on the composition,” was accepted for publication in an upcoming issue of the Journal of Agricultural and Food Chemistry.