Vitamin D or calciferol is a fat-soluble vitamin, synthesized by the body from exposure to the Sun. It maintains the level of calcium and phosphorus in the blood, and is essential for healthy bones and teeth. It helps the body absorb calcium, which in turn results in strong teeth and bones. Recent studies have revealed that vitamin D safeguards the body from hypertension, cancer and autoimmune diseases. Vitamin D, though essential for the body, can cause number of problems in case of overdose, although it is rarely seen.
Causes of Vitamin D Overdose
The daily requirement of vitamin D for the body is very low, and once the body makes enough vitamin D the process of manufacturing ceases. A person requires only 15-20 minutes of exposure to the Sun, three times a week to manufacture the required amount of vitamin D. However, when vitamin D supplements are consumed, there is no automatic shutdown mechanism, to prevent overdose of the vitamin. The levels of calcidiol increase in the blood, thereby causing toxicity. Vitamin D overdose can lead to a potentially dangerous condition called hypervitaminosis D.
Excessive ingestion of vitamin D generally takes place as a result of supplement overdose, and not due to high dietary intakes of vitamin D. Vitamin D rich foods contain high concentrations of vitamin D, however, the concentration is not high enough to cause an overdose. Although, cod liver oil is an exception to this. People suffering from rickets, osteoporosis or other conditions caused by vitamin D deficiency, are the ones who are prescribed vitamin D dosage and are most vulnerable to overdose. Moreover, as the body ages, natural synthesis of vitamin D reduces. Thus, old people need to rely on supplements for their daily vitamin D intake.
The daily recommended dosage for children and adults is 600 International Units (IU). For older folks (above 70), the recommended dosage is 800 IU. The risk of vitamin D toxicity is when a person consumes more than 10,000 to 40,000 IU per day. However, the levels vary from person to person, for example; a person consuming 15,000 IU may experience vitamin D toxicity symptoms, while another person consuming the same amount may be perfectly fine.
Symptoms of Vitamin D Overdose
Vtamin D overdose symptoms are primarily caused by the elevated calcium and phosphate levels in the blood. Moreover, the symptoms vary from individual to individual. The symptoms commonly seen are as follows:
Calcification: Abnormally high amounts of calcium and phosphate that are deposited in the soft tissue, such as kidneys, heart and lungs, is called calcification. These deposits can lead to irreversible organ malfunction. Breast calcification is one common type of calcification. Breast calcification is mostly benign, however, sometimes it can be indicative of breast cancer.
Urinary Stones: When hard mineral masses get lodged in the urinary tract region, they are called urinary stones. These stones are actually formed in the kidneys, which then move to the urinary tract. The victim goes through immeasurable pain, and most of the time, surgery is required to remove them. In some cases, a specific diet can dissolve the stones.
Nerve Symptoms: These symptoms comprise particular sensations such as numbness, pain, reflex issues, taste symptoms, hearing impairment, temperature sensitivity, tingling, burning, prickling sensations, etc.
Muscle Symptoms: Muscle weakness, loss of muscle control, muscle pain, cramps, stiffness, decrease in size and bulk of the muscle, called muscle atrophy are the various muscle symptoms occurring due to vitamin D overdose.
Bone Symptoms: Too much calcium in the blood conduces to over calcification of the bones. This results in bone pain and bone loss.
The other symptoms of vitamin D overdose are vomiting, nausea, poor appetite, excessive thirst, excessive urine production, loss of weight, abdominal pain, dehydration, constipation, diarrhea, itchy skin, severe headache, irritability and nervousness. Heart rhythm irregularities, increased risk of heart disease, high blood pressure as well as renal failure are also symptoms of the overdose. vitamin D overdose in pregnant women can result in mental or physical retardation in babies.
Vitamin D overdose is not the result of a single large dose, but is the result of a high vitamin D dosage over a period of time. This is because, the body does not excrete the excess levels of vitamin D from the body, like it does with the other essential nutrients. The excess vitamin D is stored in the fat cells of the body, where they accumulate and reach the toxic levels over a period of time. Vitamin D overdose can be treated with steroids, prescribed by a medical professional.