What are the side effects and contraindications of century eggs?
Dec 12, 2025
Source: Cainiu Health
Dr. Huang Yuhong
Introduction
Side effects of century eggs generally include kidney function impairment, interference with bone development, digestive discomfort, increased blood pressure, and nervous system stimulation. Contraindications typically include avoiding consumption by pregnant women, cautious intake by children, and avoidance by individuals with hypertension, kidney disease, or allergic constitutions. If symptoms such as dizziness, vomiting, or skin irritation occur after consumption, intake should be stopped immediately and medical attention sought.
Side effects of century eggs generally include kidney function impairment, adverse effects on bone development, digestive discomfort, elevated blood pressure, and nervous system stimulation. Contraindications typically include avoidance by pregnant women, cautious consumption by children, and prohibition for individuals with hypertension, kidney disease, or allergic constitutions. Specific details are as follows:
I. Side Effects
1. Kidney Function Impairment: Century egg production involves ingredients such as sodium carbonate and quicklime, resulting in high levels of sodium and residual heavy metals. Long-term excessive consumption increases the metabolic burden on the kidneys and may impair renal filtration function, particularly affecting individuals with pre-existing kidney weakness.
2. Adverse Effects on Bone Development: Century eggs contain high levels of phosphorus. Excessive intake interferes with calcium absorption and disrupts the body's calcium-phosphorus balance. Prolonged consumption may lead to calcium loss from bones, compromising bone health—especially detrimental to adolescents and the elderly.
3. Digestive Discomfort: As a preserved food, century eggs contain significant amounts of salt and alkaline substances. Overconsumption can irritate the gastrointestinal mucosa, potentially causing stomach pain, bloating, diarrhea, and other digestive issues. Individuals with weak spleen and stomach functions are more susceptible to these symptoms.
4. Elevated Blood Pressure: Large quantities of table salt are added during the production process. Long-term overconsumption leads to excessive sodium intake, causing water and sodium retention, increased blood volume, and consequently higher blood pressure—posing risks to cardiovascular health.
5. Nervous System Stimulation: Some century eggs may contain trace residues of lead. Chronic ingestion allows lead to accumulate in the body, stimulating the nervous system and potentially causing symptoms such as dizziness, fatigue, and difficulty concentrating. In severe cases, neurological function may be impaired.
II. Contraindications
1. Pregnant Women Should Avoid Consumption: Residual heavy metals and high sodium content in century eggs may cross the placenta and affect fetal development, increasing the risk of congenital malformations and growth retardation. Additionally, high sodium intake may加重 maternal physiological strain, leading to edema and related complications.
2. Children Should Consume with Caution: Children’s organs are not fully developed, and their kidney metabolism and nervous system defenses are relatively weak. Consuming century eggs may result in heavy metal accumulation, negatively impacting intellectual and physical development. Intake should be strictly limited or avoided altogether.
3. Hypertensive Patients Should Avoid Consumption: The extremely high sodium content in century eggs can cause a sharp rise in blood pressure among hypertensive individuals, worsening their condition and hindering blood pressure control, potentially triggering cardiovascular and cerebrovascular complications.
4. Kidney Disease Patients Should Avoid Consumption: Patients with kidney disease have impaired renal metabolic function and cannot effectively excrete excess sodium and heavy metals. Eating century eggs further burdens the kidneys, possibly exacerbating the condition and leading to progressive kidney damage.
5. Individuals with Allergic Tendencies Should Avoid Consumption: Some people may be allergic to proteins or pickling components in century eggs. After consumption, they may experience allergic reactions such as skin itching, rashes, or breathing difficulties. These individuals must strictly avoid eating century eggs.
To minimize risks, century eggs should be purchased from reputable sources to ensure quality and reduce the likelihood of heavy metal contamination. If symptoms such as dizziness, vomiting, or skin irritation occur after consumption, intake should be stopped immediately and medical attention sought.
