Vitamin A Dosage: Safety and Toxicity Concerns

Vitamin A dosage

Dear Pharmacist: I have bronchial issues, and during severe episodes, I experience wheezing.
A friend suggested that taking 15,000 IU of vitamin A and 800 IU of vitamin D daily has significantly improved my allergic reactions after a month.
How long can I take these supplements before risking toxicity? Thank you.

A Cai, 50~59 year old female. Ask Date: 2012/05/17

Dr. Ke Bowen reply Pharmacology

Dear Mr.
A-Cai,
According to the announcement by the Department of Health, Executive Yuan on February 14, 2000, the upper limit for the recommended dosage of Vitamin A has been increased from 9,750 IU to 10,000 IU per day, and the upper limit for Vitamin D has been increased from 600 IU to 1,000 IU per day.
If the daily intake of Vitamin A is below 9,750 IU and Vitamin D is below 600 IU, they may be managed as food products, but health claims cannot be made.

Although both Vitamin A and D are essential nutrients for the human body, long-term consumption of high doses may lead to vitamin toxicity.
Symptoms of Vitamin A toxicity include nausea, vomiting, headache, increased intracranial pressure, dizziness, blurred vision, and muscle incoordination, as well as bulging fontanelle in infants.
For individuals with Vitamin D toxicity, symptoms may include hypercalcemia, polyuria, extreme thirst, and hypercalciuria.
Reports have also indicated that intakes of Vitamin D as high as 50,000 to 200,000 IU can lead to central nervous system symptoms such as depression, headache, dizziness, fatigue, weight loss, anorexia, nausea, and vomiting.
Since you are taking 15,000 IU of Vitamin A and 800 IU of Vitamin D daily, which is not as per physician's instructions, there is a higher risk of vitamin toxicity.
If you experience any similar symptoms or other issues, please consult your physician for further examination and advice.
Thank you.

Reply Date: 2012/05/17

More Info

When it comes to the safety and potential toxicity of vitamin A and vitamin D, it is essential to understand the recommended dosages, the body's ability to store these vitamins, and the signs of toxicity.
Vitamin A is a fat-soluble vitamin, which means that it can accumulate in the body's tissues. The recommended dietary allowance (RDA) for vitamin A varies by age, sex, and life stage. For adults, the RDA is approximately 900 micrograms (mcg) for men and 700 mcg for women, which translates to about 3,000 IU (International Units). Consuming vitamin A in excess of 10,000 IU per day over an extended period can lead to toxicity, known as hypervitaminosis A. Symptoms of vitamin A toxicity can include nausea, headaches, dizziness, blurred vision, and even more severe effects such as liver damage and intracranial pressure increases.

In your case, taking 15,000 IU of vitamin A daily is significantly above the safe upper limit. While you may notice improvements in your bronchial symptoms, it is crucial to consider the long-term implications of such high doses. If you continue this regimen, you may be at risk for developing toxicity, especially if taken for an extended period. It is advisable to monitor for any signs of toxicity and consult with a healthcare professional to adjust your dosage appropriately.

Vitamin D, on the other hand, is also a fat-soluble vitamin, and its RDA is about 600 IU for adults, with an upper limit set at 4,000 IU per day. While vitamin D is essential for bone health and immune function, excessive intake can lead to hypercalcemia (high levels of calcium in the blood), which can cause nausea, weakness, and kidney complications. Your intake of 800 IU is within the safe range, but it is still important to be cautious, especially if you are taking other supplements or medications that may affect your vitamin D levels.

Given your bronchial issues and the improvements you've experienced, it is crucial to balance the benefits of supplementation with the risks of toxicity. It is recommended to have regular check-ups with your healthcare provider, who may suggest monitoring your vitamin A and D levels through blood tests. This way, you can ensure that you are within a safe range while still addressing your health concerns.

In summary, while vitamins A and D can provide health benefits, particularly in individuals with deficiencies or specific health conditions, it is vital to adhere to recommended dosages to avoid toxicity. Always consult with a healthcare professional before making any significant changes to your supplement regimen, especially when dealing with chronic health issues.

Similar Q&A

Eye Health Supplements: Key Considerations and Dosage Guidelines

Hello, Nutritionist: I would like to consult you regarding eye health supplements. I purchased an eye care "product" that does not list vitamin A as an additive in the ingredient list, but it contains beta-carotene (the dosage is not specified). The nutritional label in...

Dr. Cai Xiuwen reply Nutrition
Hello! According to the announcement by the National Health Administration, the Dietary Reference Intakes for Taiwanese (7th edition, revised in 2011) states that high doses of "preformed" vitamin A have significant toxicity. However, long-term intake of high doses of b...

Does Excess Vitamin A Affect Muscle Growth and Nutrient Absorption?

Excessive intake of Vitamin A, such as 15,000 IU, can indeed have implications beyond eye protection. It may interfere with muscle function, bone health, and overall development, potentially affecting growth in height. Additionally, high levels of Vitamin A can hinder the absorpt...

Dr. Zhang Yuzhang reply Physical Fitness
Dietitian Tsai Pei-Fen from Tainan Hospital, Department of Health, responded to an online inquiry: Generally speaking, Vitamin A is a fat-soluble vitamin. Long-term high doses, approximately 70,000 to 100,000 units daily, can lead to accumulation in the body, with primary symptom...

Vitamin A Intake Limits for Chronic Hepatitis B Carriers

I have been a carrier of hepatitis B for over 20 years. Recently, my tests showed GOT 62 and GPT 94. Currently, I am taking a multivitamin that contains 5000 IU of vitamin A and 5000 IU of beta-carotene, taken twice daily. For someone like me with poor liver function, is there a ...

Dr. Huang Shuli reply Nutrition
According to the revised Dietary Reference Intakes for Taiwanese citizens by the Department of Health in 2002, the adequate daily intake of vitamin A for adult males is 600 micrograms (equivalent to 2000 IU), and for females, it is 500 micrograms. The upper limit for adults is se...

Vitamin A Supplementation for Dry Eyes: Safe Practices and Recommendations

Hello, pharmacist. I have dry eye syndrome and am considering supplementing with vitamin A. However, the pharmacy staff advised against taking it alone due to potential accumulation in the body and its effects. Aside from the usual intake of fruits and vegetables, how can I bette...

Dr. Hou Fangmin reply Pharmacology
Hello: 1. Vitamin A is a fat-soluble vitamin that is not easily metabolized and can lead to liver damage. Symptoms of acute and chronic vitamin A toxicity include nausea, headache, hair loss, fatigue, loss of appetite, dizziness, dry skin, peeling, cerebral edema, hepatosplenom...