Another egg-related study, published in the Journal of Nutrition, found that eating one egg per day can increase levels of both lutein and zeaxanthin in the bloodstream. Researchers found that lutein levels were increased by 26% and zeaxanthin levels by 38% during the weeks that study participants consumed one egg per day. The research team also made note that adding a daily egg to participants’ diets did not increase total, LDL, or HDL cholesterol or triglycerides—an important fact for those who are still wary of eating eggs.