Preserved eggs contain lead, which will have a bad influence on the absorption of nutrients in the body and may lead to iron deficiency and zinc deficiency. In addition, preserved eggs contain many alkaline substances, which will quickly neutralize gastric acid after eating, thus reducing the barrier protection of gastric juice on the stomach and affecting the digestion and absorption of food by the human body. Moreover, the nitrite in preserved eggs is very rich, which will increase blood pressure after eating, so you can't eat more.