What are the dangers of excessive vitamin A?

Vitamin A has many benefits to the human body. For example, it can improve eyesight. Vitamin A also helps the growth of human bones and is beneficial to the maintenance of human gonad function. However, vitamin A should be consumed in moderation and not too much. If too much vitamin A is consumed, it will cause poisoning. Acute poisoning may cause dizziness, headache, nausea, vomiting, diarrhea, etc. Chronic poisoning can cause bone and joint pain, swelling, itchy skin, physical weakness, mood swings, and scanty menstruation. What are the dangers of excessive vitamin A? Let’s take a look at it next.

1. Vitamin A Excess​

Many people mistakenly believe that the more vitamin supplements they take, the better, so they take vitamin drugs for a long time. Little do people know that everything has its limits. If the human body is not lacking in vitamins, taking large doses of vitamins will not only cause waste, but may also cause various adverse reactions.

2. Hazards​

There are so many different vitamin products on the market today that it is hard to keep up. However, experts warn that excessive intake of vitamins will not only fail to ensure nutritional balance, but may also bring unexpected dangers.

Many people mistakenly believe that the more vitamin supplements they take, the better, so they take vitamin drugs for a long time. Little do people know that everything has its limits. If the human body is not lacking in vitamins, taking large doses of vitamins will not only cause waste, but may also cause various adverse reactions.

Vitamin A plays an important role in bone growth and maintenance of gonadal function, but excessive intake can also lead to poisoning. Acute poisoning is manifested by symptoms such as dizziness, drowsiness, headache, vomiting, and diarrhea. Chronic poisoning manifests itself as bone and joint pain, swelling, skin itching, fatigue, limb weakness, irritability, abdominal pain, and oligomenorrhea in women.

3. Adverse Reactions

Chronic hypervitaminosis A is mostly caused by long-term excessive intake. The dose that causes chronic poisoning varies with age and also varies from individual to individual, with infants being more sensitive than adults. Adults who consume 24 to 30 mg (80,000 to 100,000 IU) per day for half a year, or 9 to 12 mg (30,000 to 40,000 IU) per day for more than 8 years may suffer from chronic poisoning. If infants and young children consume 15 to 30 mg (50,000 to 100,000 IU) per day for more than 6 months, they may suffer from chronic poisoning. There are also reports that infants and young children may suffer from poisoning symptoms within one month if they consume only 7.5 mg (25,000 IU) per day. The clinical manifestations of chronic vitamin A poisoning in adults often first manifest as decreased appetite and weight loss, followed by dry, scaly, and cracked skin, dry hair, hair loss, red and swollen gums, chapped lips, and nosebleeds. Complaints of pain at the muscular junction of long bones, accompanied by swelling. Cortical bone hyperplasia, periosteum thickening, hepatosplenomegaly, and anemia. The cerebrospinal fluid pressure may increase, and mastoid pseudotumors may occasionally form in the brain. Hypercalcemia, hypercalciuria, and cirrhosis sometimes develop. Infants and young children often suffer from anorexia and irritability.

4. Symptoms of poisoning

1. Changes in the skin and mucous membranes often manifest themselves in different ways, with dry and rough skin, or thin and shiny skin, seborrhea-like rash or scattered maculopapular rashes all over the body, accompanied by flaky peeling or desquamation, and severe itching. The hair is dry, sparse, brittle and prone to hair loss.

2. Increased intracranial pressure is more common in infants. The anterior fontanelle may be full and bulging, the head circumference may be enlarged, and the sutures may be separated. There may be headaches, vomiting, crying and restlessness. The increased intracranial pressure may be related to excessive cerebrospinal fluid secretion or absorption disorders. After stopping the medication, the intracranial pressure returns to normal slowly, and taking vitamin A again may increase the pressure.

3. Changes in the skeletal system: Metastatic bone pain mostly occurs in the long bones of the limbs, especially in the forearm and calf, involving the ulna, radius, tibia, and occasionally the ribs, accompanied by local soft tissue swelling and tenderness, but no local signs of fever or redness. It can also appear in the temporal bone and occipital bone, which can be mistaken for craniomaslasia. Bone pain may occur repeatedly in the same area or in different areas at the same time.

4. Liver disease: Excessive intake of vitamin A is toxic to the liver and damages the liver parenchyma. The liver and spleen may become enlarged, transaminase may increase, and it may even cause cirrhosis, accompanied by portal hypertension and ascites. There are reports that liver biopsy showed infiltration of inflammatory cells in the liver parenchyma and an increase in sinusoidal adipocytes. The liver and spleen returned to normal two months after stopping vitamin A.

5. Long-term excess of vitamin A affects growth and development, especially during the critical period of fetal development, if the pregnant mother consumes too much vitamin A, it can cause fetal malformations. Extensive malformations of the nervous system, craniofacial bones, cardiovascular system, and urogenital system often occur. Animal experiments have also confirmed this teratogenic effect.

6. Others may have kidney diseases. Bone absorption can increase blood calcium, urine calcium, and hyperuricemia. The blood system may be accompanied by hypoplastic anemia and a decrease in white blood cells. Abnormal liver function, low prothrombin, and epistaxis and gingival bleeding may occur.

5. Acute poisoning

Systemic manifestations include symptoms of increased intracranial pressure, headache, drowsiness, nausea, vomiting, and even death.

6. Chronic poisoning

Symptoms include hepatosplenomegaly, hair loss, dry skin, and swollen and painful long bones.