Can You Take Too Much Vitamin D?

Vitamin D deficiency is a global issue. It is estimated that 40% of the population are deficient, and most of them are asymptomatic. As fat-soluble, vitamin D helps the body to absorb and retain calcium and phosphorus, which are essential for building and maintaining healthy bones and teeth. It also plays a role in the proper functioning of the immune system.

There are three major sources of vitamin D: your body makes it when your skin is exposed to the sun; a diet rich in fatty, cold water fish such as salmon, swordfish, tuna, mackerel, sardines, fortified milk, dairy products, and orange juice; and supplementation. It is difficult to get adequate vitamin D from the sun and few people eat the necessary foods to maintain a steady level of adequate vitamin D intake. And if most people are unaware of their deficiency, it’s unlikely that they are supplementing. The only way to confirm that you are either deficient or sufficient is to have a blood test.

While vitamin D toxicity is rare, it is a potentially serious side effect that results from having excess amounts of vitamin D in your body. Though it would take a healthy person an extremely large dose of vitamin D supplements to reach toxicity, it is real and could cause major health problems if undetected.

What Causes Vitamin D Toxicity?

Vitamin D toxicity, also known as hypervitaminosis D, or its clinical manifestation - severe hypercalcemia –is related to long-term, excessive intake of vitamin D, malfunctions of the vitamin D metabolic pathway, or the existence of disease that produces vitamin D metabolite locally. It is very uncommon and is not typically caused by deficient diet or lack of sun exposure. No food, even fortified, contains large enough amounts of vitamin D to cause toxicity, and the body regulates the amount of vitamin D produced as a result of sun exposure.

Exogenous vitamin D deficiency is usually caused by inadvertent or improper intake of extremely high doses of (typically prescription strength) vitamin D preparations. At Care/of the vitamin D formula contains only 25 mcg (1,000 IU) of vitamin D per capsule. Taking 1500 micrograms (mcg) or 60,000 international units (IU) a day of vitamin D for several months without proper guidance and regular lab measurements of vitamin D levels has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 15 mcg (600 IU) of vitamin D a day.

Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame. Blood levels should be monitored while taking high doses of vitamin D.

What Are The Signs And Symptoms Of Vitamin D Toxicity?

In order for vitamin D to reach toxic or dangerous levels in the body, it needs to exceed 100 nanograms (ng) per mL. This is defined as hypervitaminosis D, while vitamin intoxication is defined as serum levels over 150 ng/mL. Normal vitamin D levels between 30-60 ng/mL are ideal for optimal benefit. High Levels of Vitamin D can cause increased blood calcium levels (hypercalcemia).

Symptoms of hypercalcemia can include:

• Gastrointestinal distress, including nausea, vomiting, constipation, and diarrhea
• Loss of appetite
• Kidney complications
• Fatigue, dizziness, confusion, agitation, unresponsiveness
• Bone pain
• Frequent urination (Polyuria)
• Excess thirst (Polydipsia)
• Dehydration

It should be noted that these symptoms are not specific to high levels of calcium and any new symptoms or health concerns should be addressed with your doctor.

Vitamin D Deficiency vs Toxicity

A deficiency means you are lacking the necessary baseline levels of a certain vitamin or mineral. The only way to tell if you are insufficient or deficient is to have a healthcare professional test your vitamin D blood serum levels. A circulating level of 25-hydroxyvitamin D greater than 30 ng/mL is required to maintain a healthy level of vitamin D. Chronic unaddressed vitamin D deficiency can lead to an array of bone problems.

Toxicity means you have taken too much of a vitamin or mineral, and the excess has led to unwanted side effects. Vitamin D toxicity would result in high blood levels of vitamin D, 150 ng/mL, and calcium. You might also experience vomiting, nausea, constipation, diarrhea, appetite changes, confusion, or agitation. Prolonged toxicity could lead to kidney complications and bone issues.

How To Prevent Vitamin D Toxicity

Vitamin D toxicity is usually caused by large doses of vitamin D supplements, not by diet or sun exposure. Before you begin to take vitamin D supplements, consult your physician or healthcare provider. A blood test may be taken to determine your blood levels. If a deficiency needs to be corrected, your physician will determine how much vitamin D you should take and for what duration of time. Most typically, your vitamin D levels will be monitored by regular blood work. Avoid megadoses of vitamin D. At Care/of the vitamin D formula contains only 25 mcg (1,000 IU) of vitamin D per capsule. Taking 1500 micrograms or 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 15 mcg (600 IU) of vitamin D a day.

The Bottom Line

Vitamin D supplements are considered very safe, and toxicity is uncommon. A healthy person would need to take extremely large doses of vitamin D over an extended period of time in order to reach dangerous or potentially toxic levels in the body. The only way to know if you are deficient or insufficient is to have your healthcare provider test your vitamin D level. Most cases of vitamin D toxicity are caused by inappropriate supplement dosing and prescription errors.

Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame. Blood levels should be monitored while someone is taking high doses of vitamin D.

The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can lead to serious complications. Treatment includes stopping vitamin D intake and restricting dietary calcium. Your doctor might also prescribe intravenous fluids and medications.

Increased public awareness of vitamin D-related health benefits might increase the risk of vitamin D toxicity due to self-administration of vitamin D in higher doses than what is recommended for the particular demographic.

As always, talk to your doctor before taking vitamin and mineral supplements.