One of vitamin D’s functions is to help your body to absorb calcium. The more vitamin D you take in, the more calcium is released into your bloodstream. If you get vitamin D in excess, your calcium concentration also gets too high, creating gastrointestinal problems. Before supplementing vitamin D, verify with your doctor that it can benefit you and follow her dosage instructions to prevent harmful effects.
Hypervitaminosis D and Hypercalcemia
Toxic levels of vitamin D, a condition called hypervitaminosis D, are usually provoked by excessive doses of prescription-strength supplements or more than 50,000 IU of vitamin D daily. The over-supplementation can cause hypercalcemia -- too much calcium in your bloodstream. The gastrointestinal symptoms of hypercalcemia are nausea, constipation, abdominal pain, decreased appetite and vomiting.
Addressing Hypervitaminosis D
Supplement vitamin D under your doctor’s supervision. If you accumulate a high level of the nutrient in your body, follow her instructions to lower it back to normal. Your physician may suggest, for instance, that you suspend vitamin D supplementation altogether. She might also check your calcium supply. If she determines you are hypercalcemic, she may recommend treatment for the condition. Depending on its severity, you might need to take diuretics, receive fluids intravenously or undergo dialysis to dilute and excrete the calcium.
Avoiding Hypervitaminosis D
According to the Linus Pauling Institute, few foods offer vitamin D. Most of your supply comes from the interaction between the sun and your skin. Spending about 10 minutes outside two to three times weekly provides your body sufficient energy to produce its own supply of vitamin D. It also prevents supplement overdoses that lead to excess vitamin D, too much calcium and the resulting gastrointestinal problems.
Befriending the Sun
In sunny Australia, where the population shields its skin from the sun with layers of sun block and clothes to prevent cancer, vitamin D deficiency has become a problem. The ozone hole above the country results in high ultraviolet radiation reaching Earth’s surface, which carries the risk of skin cancer. Low vitamin D is also more common among dark-skinned individuals, whose pigments are a natural barrier against the sun. Women who veil themselves and home-bound individuals show the same propensity to be deficient in the nutrient. Some sunscreen lotions reduce your body’s vitamin D production by 95 percent, says the Linus Pauling Institute. If you have concerns about exposing your skin to the sun, consult a dermatologist -- a skin doctor. If she advises you against any sun exposure, work with your primary care physician to create a diet and supplementation plans that are least likely to cause hypercalcemia and its gastrointestinal symptoms.
References
- Linus Pauling Institute; Vitamin D; Jane Higdon, Ph.D., et al.; June 22, 2011
- PubMed Health; “Hypercalcemia”; Robert Cooper, M.D., et al.; Jan. 21, 2010
- PubMed Health; Hypervitaminosis D; Ari S. Eckman, M.D., et al.;
- “Medical Journal of Australia”; Megadose Therapy for Vitamin D Deficiency; Peter R. Ebeling; 2005
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