Vitamin D occurs naturally in some foods and is often added to others. However most people receive their intake through dietary supplements or exposure to sunlight. It is produced when sunlight hits the skin. In fact, the term "vitamin" is a misnomer since vitamin D is closer to a hormone.
Overdoses can occur with most vitamins but generally are not harmful. However, because vitamin D is a hormone, there are consequences that come with high intake levels that should be taken seriously.
Toxicity from Vitamin D
Vitamin D is stored in fat cells and not excreted like most other vitamins. However for intake to reach toxic levels, it is generally a gradual process and not a one-time event. The daily recommended dosage of vitamin D has been debated in recent years. Initially, it was thought that 200 to 600 IU (International Units) per day were sufficient. But that number has been raised to approximately 1,000 IU per day. For most people some exposure to the sun every day can help fulfil that requirement. However some doctors suggest that people in northern climates who do not have as much exposure to the sun add supplements to their diet. Toxicity becomes an issue when upper intake levels are reached on a consistent basis. For most people, these levels are around 100,000 IU per day. Even still, for an overdose to occur, a person would need to reach those levels for a few months before symptoms begin to appear.
Symptoms of Vitamin D Overdose
The symptoms of vitamin D overdose can vary from mild to serious. Some, like nervousness and irritability, are emotional. But physical signs can start to appear as nausea, vomiting, loss of appetite and accompanying weight loss. Sufferers may also become dehydrated and experience increased thirst and severe headaches. As symptoms progress, the nerves and muscles become affected, leading to itchy skin, fatigue and weakness. More serious issues of vitamin D toxicity in the body leads to elevated levels of calcium that reside in the blood and soft tissues (like the lungs, heart and kidneys). At this point, bone pain or bone loss can occur. Sufferers will also exhibit urinary tract symptoms ranging from excessive production of urine to kidney stones or renal failure. High blood pressure and an increased risk of heart disease are concerns and ultimately can lead to irrevocable damage to major organs.
Diagnosis of Vitamin D Overdose
Because overdoses are rare and have few symptoms that identify it exclusively, diagnosis can be difficult. One of the determining factors is whether a person has had large doses of vitamin D for an extended period of time. If you are concerned that you may have experienced vitamin D toxicity, consult your physician who can conduct other tests and recommend necessary treatments.
Treatment of Vitamin D Overdose
The solution to vitamin D overdose is generally simple and includes limiting its intake for a specified period of time. However it may take time for some of the symptoms to subside. Because excess vitamin D is stored in fat cells, the side effects may not start to wane until those reserves are exhausted.
Risk Factors of Vitamin D Overdose
While Vitamin D overdose is a possibility with serious consequences, it is very rare. Most people will not approach the upper intake levels and those that do generally will not reach them often enough to trigger any type of overdose symptoms. If you are concerned about your vitamin D intake, contact your doctor who can answer any questions you have. You can not overdose on vitamin D becaues of exposure to the sun or through food sources. Overdose of vitamin D comes from excessive amounts in supplements.