Vitamin D ingested in excessive amounts can cause constipation.
Excessive Vitamin D
Excessive amounts of Vitamin D can cause nausea, weakness, fatigue, poor appetite, and weight loss as well as constipation. In higher amounts, excess intake of vitamin D has the potential to cause heart rhythm abnormalities, confusion, and can increase the body’s blood calcium level, which can lead to kidney stones.
Vitamin D a Fat-Soluble Vitamin
Vitamin D is a fat-soluble vitamin, which by definition means the body will store the vitamin until it is needed by the body. Generally, a fat-soluble vitamin carries more of overdose than a water-soluble vitamin because it compounds over time. Vitamin D can be obtained through food and exposure to sunlight.
Excessive Vitamin D Intake from Food
It is highly unlikely that the body can get too much vitamin D from food alone. Because very few food sources contain vitamin D naturally, many foods such as milk and cereal are fortified with vitamin D. Even with the addition of vitamin D, only 29% of adult American men and 17% of adult American women get the recommended daily intake of Vitamin D through food sources.
Excessive Vitamin D Intake from Sun Exposure
Most people receive an adequate intake of vitamin D through sun exposure. Excessive intake of vitamin D from sun exposure is thought to be unlikely as the constant heat on the skin photodegrades the vitamin.
Excessive Vitamin D Intake from Supplements
The most likely way to ingest excessive amounts of vitamin D is through supplementation. The recommended daily intake for both adult men and women, ages 19-50 is 5mg/200IU. But according to recent studies, the body can handle ingesting far more vitamin D safely, the upper limits of which have been tested safely at 10,000 IU for healthy adults.
Moshfegh A, Goldman J, Ahuja J, Rhodes D, LaComb R. 2009. What We Eat in America, NHANES 2005-2006: Usual Nutrient Intakes from Food and Water Compared to 1997 Dietary Reference Intakes for Vitamin D, Calcium, Phosphorus, and Magnesium. U.S. Department of Agriculture, Agricultural Research Service. [http://www.ars.usda.gov/ba/bhnrc/fsrg]
“Dietary Supplement Fact Sheet: Vitamin D.” Office of Dietary Supplements – HOME. N.p., n.d. Web. 4 Oct. 2010. http://ods.od.nih.gov/factsheets/vitamind.asp.
Byrdwell WC, DeVries J, Exler J, Harnly JM, Holden JM, Holick MF, et al. Analyzing vitamin D in foods and supplements: methodologic challenges. Am J Clin Nutr 2008;88:554S-7S.
Holick MF. Vitamin D deficiency. N Engl J Med 2007;357:266-81