Vitamin D is made in the body through exposure to sunlight. As the days grow shorter, people often turn to supplements. Supplements can be an excellent way to make sure you fill gaps in your nutritional needs. But when it comes to vitamin D, you can have too much of a good thing.
Vitamin D is needed for overall health, but also helps specific regions of the body. It is sometimes added to milk as it helps you absorb calcium. However, as it is a fat-soluble vitamin, if the milk is fat-free and you aren't consuming any fat with your milk, the vitamin isn't likely to be absorbed. Vitamin D also helps heart and nerve health, along with muscle function and the immune system. Vitamin D deficiency can cause osteoporosis, malabsorption disorders, kidney and liver diseases, neurological and mood disorders, problems during pregnancy and rickets.
The amount of vitamin D a person needs changes throughout their life. A newborn needs 1,000 IU while adults need 4,000 IU. That includes vitamin D from the sun, food and supplements. Depending on where you live, the time of year, and how light or dark your skin is, you may be able to get enough vitamin D from daylight alone. Five to 30 minutes of sunlight on uncovered, unprotected arms and legs between 10 in the morning and four in the afternoon twice a week may be enough to hit your requirement. Plus, it is in egg yolks, fatty fish, mushrooms grown in UV light and fortified foods.
Too much vitamin D can be unhealthy, potentially deadly. Vitamin D toxicity usually occurs over time as it builds up in the body. It cannot happen from sun exposure and rarely from food. It's almost always from supplements. The technical term for vitamin D toxicity is hypervitaminosis D.
"Unlike other vitamins, vitamin D acts like a hormone, so an excess of it in your body can lead to other health problems, such as hypercalcemia (high levels of calcium in your blood)," said Maria Haddad-Garcia, editorial manager of nutrition and news, at Eating Well. "This buildup of vitamin D in your body may happen when you take very high doses of vitamin D for several months. Additionally, since vitamin D is fat-soluble, your body can't get rid of it like it does with water-soluble vitamins."
"While vitamin D is essential to maintain strong bones and muscles, there is such a thing as too much of a good thing. When there are elevated levels of calcium in our blood, it can cause damage to soft tissues, bones, kidneys and arteries," said Dr. Benjamin Barlow, chief medical officer of American Family Care.
Vitamin D toxicity can cause kidney failure, irregular heartbeat and, potentially, death. It's essential to take only the recommended amount of a vitamin D supplement. Symptoms of vitamin D toxicity include nausea or vomiting, decreased hunger, constipation, muscle weakness, confusion, bone pain, dehydration and thirst, excessive urination and kidney stones. If you experience any of these symptoms, stop taking vitamin D and talk to a doctor.
