Toxicity Levels Of Vitamin D

Vitamin D plays important roles in immune function and maintaining normal levels of calcium and phosphorus in your blood. In your diet, you obtain vitamin D from dairy products, fish, eggs and vitamin-fortified cereals. According to MayoClinic.com, you should take no more than 5 mcg of vitamin D a day if you are under age 50. If you are between the ages of 50 to 70, take 10 mcg daily. However, long-term high intake of vitamin D -- called hypervitaminosis D -- can cause many disorders and problems in your blood, kidneys and soft tissues.

Toxicity Level

You can develop vitamin D toxicity if you take more than 1,200 mcg of vitamin D a day over a period of several months, according to former nutrition professor Gordon Wardlaw of Ohio State University. However, you should not be too concerned with overdosing because your body stores excess vitamin D in your fat tissues and it does not accumulate easily in your blood. Vitamin D deficiency is more common than accumulating toxic levels.

Calcification

Calcification is the deposit of calcium in your soft tissues. Because vitamin D helps your body absorb more calcium, extra calcium minerals that are not absorbed by your bones get deposited in your arteries, connective tissues, lungs, heart and skeletal muscles. According to Wardlaw, this is an irreversible process that eventually damages the organs. One way to remove calcium from these areas is with arthroscopic surgery. This works only during the early stages of calcification.

Kidney Stones

Kidney stones, which are made up of calcium oxalate, form when you have excess calcium concentrations in your blood. When your kidneys filter calcium from your bloodstream, some of these calcium deposits gradually build up in the kidney cavities. According to the National Kidney and Urologic Diseases Information Clearinghouse, vitamin D toxicity can increase the risk of kidney stones, along with excess calcium intake and hyperoxaluria -- a condition where your body produces too much oxalate, which is a type of salt.

Symptoms and Susceptibility

Other common and less severe symptoms include nausea, vomiting, headaches, and high blood pressure. According to Oregon State University's Linus Pauling Institute, people who suffer from certain diseases such as hyperparathyroidism, sarcoidosis and tuberculosis are more susceptible to hypervitaminosis D because their bodies are very sensitive to vitamin D absorption.

Prevention

Wardlaw suggests that you avoid foods or supplements that have more than 50 percent of the recommended daily vitamin D intake per serving, unless you have a medical reason that is identified by a physician or registered dietitian.