Can You Actually Overdose on Vitamins?

My Doctor Finder
August 31, 2022

It pays to have a healthy body– especially with the times we have. There are many ways to build a healthy body, but one of the best ways to do it is to give your body the recommended dietary allowance (RDA) of vitamins and minerals.

These vitamins and minerals strengthen the immune system and improve body functions. For example, Vitamin C bolsters the immune system and Vitamin A is important for eye health.

An individual can get their daily RDA of different vitamins by eating vitamin-rich food and by taking supplements. These days, sources of vitamins are so easy to access. Everything you eat and drink from fruits, meats, bread, bottled water— even candies are fortified with vitamins!

When you pair eating vitamin-rich meals with taking vitamin supplements, it is possible to exceed the vitamin RDA before the end of the day without knowing it. But did you know that overdosing on vitamins has a negative effect on your body?

In this article, we will review the negative effects of excessive amounts of vitamins in the body.


1.      Vitamin A

Vitamin A (retinol, retinoic acid) is important for vision, eye health, bone health, cell growth, and the production and activity of white blood cells. Aside from that, Vitamin A has antioxidant properties that protect your cells from free radicals, substances that damage the cells and cause aging.

Adult males 19 years and older have 3,000 IU (900 mcg) RDA and females of the same age group have 2,333 IU (700 mcg). Going over 3,000 mcg in a day is still tolerable but going further above can cause Hypervitaminosis A.

Hypervitaminosis A is a disorder that can cause:

·         Abnormal softening of the skull bone in infants and children

·         Blurry vision

·         Bone pain or swelling

·         Nausea

·         Vomiting

·         Dry skin

·         Sensitivity to bright light

·         Birth defects

·         Bone loss

·         Hip fracture

·         Liver damage

·         Kidney damage

·         Interference with vitamin D benefits


2.      Vitamin C

Vitamin C is one of the most important nutrients your body needs. This vitamin is an antioxidant that helps protect the body from different diseases by boosting the immune system. It also helps the body form blood vessels, cartilage, muscle, and collagen in bones, and in the body’s healing and recovery.

The RDA for vitamin C is 90 mg for adults 90mg for men and 75 mg for women. Most people get their RDA from their food alone but taking supplements can help too.

Vitamin C is safe when taken at correct doses. However, the body’s absorption of vitamin C decreases to below 50% when taking doses above 1000 mg. Taking amounts higher than 3000 mg daily can have adverse effects on the body:

·         Nausea

·         Vomiting

·         Diarrhea

·         Stomach cramps

·         Bloating

·         Fatigue

·         Sleepiness

·         Insomnia

·         Headache

·         Skin Flushing

·         Increase in uric acid levels (increasing risk of gout)

·         Increase the formation of kidney stones in people with kidney disease or those with a history of kidney stones


3.      Vitamin D

Vitamin D is an essential nutrient that helps the body absorb and keep calcium and phosphorus to help in bone building. Without sufficient vitamin D, bones will become thin, brittle, misshapen, and more prone to damage.

Another benefit you can get from vitamin D is the risk reduction of developing cancer. In a 2006 study published in the American Journal of Public Health, they found that adequate amounts of vitamin D in the body can help reduce the risk of developing breast, colon, or prostate cancer.

But what is the RDA of vitamin D? Both adult men and women (19 years old and above) need 15 mcg of vitamin D, while adults over 70 need 20 mcg. Going over the RDA doesn’t have adverse health effects but megadosing on vitamin D for a long time can become toxic.

Although rare, vitamin D toxicity (hypervitaminosis D) can cause severe effects in the human body. The research of A Asif and N Farooq states that vitaminosis D can lead to hypercalcemia and imbalance in regulating bone metabolism.

To further explain, hypercalcemia is a condition that happens when the calcium levels in the blood are too high. This results in bone weakening, creation of kidney stones, and interfere with the heart and brain.


4.      Vitamin E

Vitamin E is important to skin, eye, blood, and brain health. It also acts as an antioxidant that protects the cells from free radicals which cause certain diseases. 

Taking large amounts of vitamin E for a long time rarely causes harm. But in those rare cases, excessive vitamin E can cause bleeding and cause the blood to clot less. Other side effects include weakness, fatigue, nausea, and diarrhea.


5.      Vitamin K

Vitamin K is an important nutrient that helps with blood clot and prevent excessive bleeding. An adult person has an RDA of 120 mcg for men and 75 mcg for women.

Vitamin K overdose is rare but when it happens, vitamin K toxicity occurs and may cause jaundice, hyperbilirubinemia, hemolytic anemia, and kernicterus in infants as one study suggests.


With all this said, it is important to take note that getting large amounts of these vitamins from food are usually good and will not cause side effects. However, vitamin toxicity may happen if you take high doses of vitamin supplements for a long time.

Like with everything in life, it is best to take vitamins in the recommended amount to keep yourself healthy. Although the mentioned side effects are rare, they can still cause severe health problems. 




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