Vitamin D is an essential vitamin most known for its ability to absorb calcium in the body and strengthen bones. Osteoporosis, a disease that causes brittle bones, affects 200 million women worldwide, according to the International Osteoporosis Foundation, most of whom are over the age of 50. There are three ways of getting the recommended daily allowance, or RDA, of vitamin D: through diet, sunshine and supplements. Only supplementation has ever been associated with hypervitaminosis.
Tolerable Upper Intake
The RDA of vitamin D for women, according to the Office of Dietary Supplements, is 600 IU for those between the ages of 1 and 70, including women who are pregnant and breastfeeding, and 800 IU for those 71 years and older. The tolerable upper intake -- the amount that is least likely to cause adverse side effects in most people -- is 4,000 IU for all females over the age of 9, including those who are pregnant and lactating.
Side Effects
It takes about 10,000 to 40,000 IU per day of supplemental vitamin D over a long period of time for these side effects to occur. Health risks associated with hypervitaminosis D are often nonspecific, according to the ODS. Taking too much can raise blood levels of calcium, leading to heart, kidney and blood vessel damage; cause an irregular heartbeat, weight loss and increase urinary output.
Dangers
The Food and Nutrition Board reports that increases in all-cause mortality -- or death from any cause -- has been seen as a result of vitamin D toxicity in lower amounts. Taking more than 5,000 IU has been linked to greater risk of cancer -- especially in the pancreas -- cardiovascular events and more falls and fractures. In women, heart disease is more fatal than any other disease, according to the National Coalition for Women with Heart Disease. Women are also disproportionally affected by osteoporosis, falls and broken bones.
Sunshine
Going outside with exposed arms, legs and much of your torso could result in absorbing about 10,000 IU of vitamin D, clearly above the RDA. The ODS reports, however, that the body has a built-in mechanism for preventing vitamin D toxicity from sun exposure. Additionally, it's nearly impossible to exceed the RDA of the vitamin through diet alone, making toxicity very rare in people who don't take supplements.
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