Vitamin D, while important for proper bone development and calcium utilization, can also cause serious problems taken in high doses. Vitamin D overdose and toxicity is very rare, and can only occur by taking supplements since there are no foods that have high enough concentrations to cause blood levels to rise to dangerous levels. The most serious complications of a vitamin D overdose involve the overabsorption of calcium in the intestines which later causes problems as the calcium is stored in undesirable locations throughout the body. The recommended amount of Vitamin D to be consumed each day is 5-10mcg. Problems associated with a vitamin D overdose and toxicity occur when a person consumes over 50mcg/day for an extended amount of time, usually at least a few weeks.
The most common cause of vitamin D overdose and toxicity occurs when vitamin D in pill form is taken incorrectly. There are also several nutritional supplements that contain very high amounts of vitamin D, which when taken incorrectly can cause the body to gradually reach toxic levels. The most common of these supplements is Cod Liver Oil. Individuals taking either a multivitamin or supplements such as Cod Liver Oil need to pay close attention to the instructions on the labels. While vitamins and minerals are needed for good health, too much of them can also cause serious problems.
The most serious symptoms of a vitamin D overdose involve calcium absorption in the intestines and later storage in the body. Vitamin D is used by the body to facilitate the transport of calcium from food, through the intestines, into the bloodstream. When there is too much vitamin D in the body, too much calcium is absorbed and the body does not have a mechanism to safely remove the excess. The body ends up storing the calcium in places that can be harmful to the body. The most problematic areas involve the heart, lungs and kidneys. In each of these areas, the calcification of the tissue (deposition of calcium) results in the inability of the tissue to function properly. This is most noticeable in the kidneys, where the excess calcium can quickly cause kidney failure. Kidney failure caused by calcium is irreversible and the damage permanent.
In less severe cases of vitamin D overdose, more moderate symptoms can occur. One of the most commonly seen consequences of a vitamin D overdose are kidney stones, which are usually composed of calcium. There are other symptoms that sometimes occur such as nausea, vomiting and other digestive problems. High calcium levels in the bloodstream can also result in anorexia.
Another frequent symptom seen with vitamin D overdose is associated with its function of controlling blood pressure. When there is too much vitamin D and calcium present, blood pressure will gradually increase. This can result in a number of symptoms such as frequent headaches and nose bleeds. High blood pressure also can contribute to kidney damage and failure.
While vitamin D is manufactured in the body in the presence of sunlight, it is impossible for a person to overdose or reach toxic levels of vitamin D as a result of this production. The chemicals that the body uses to compose vitamin D are found in limited quantities in skin cells. Once the body has used sunlight to turn these chemicals into vitamin D, it takes a long time for these precursor chemicals to be replaced. So vitamin D production ceases while the skin cells wait.
Finally, it needs to be mentioned that vitamin D in excess amounts in pregnant women can cause serious problems with fetal development. The most common problems include mental retardation and facial deformities. It is imparative that pregnant women cease taking any supplements except those recommended by her doctor.
Vitamin D is both obtained through food and can be produced in the body. Because there are no foods that contain excessive amounts of vitamin D and the body is incapable of overproducing the nutrient, the only way to reach overdose or toxic levels is through the consumption of pills or other supplements. The real danger of an overdose comes not from vitamin D itself, but from the fact that excessive levels of vitamin D allow the body to absorb excessive amounts of calcium. This excess calcium then causes damage when it is stored in tissues throughout the body. The most frequent problem associated with Vitamin D overdose and toxicity involve the kidneys. Kidney stones occur frequently, and in prolonged cases, complete kidney failure can occur.
