If you go over your daily recommended doses and take too much vitamin D, you can encounter some or all of the following side effects (depends on dosage): vomiting, constipation, dehydration, irritability, bone pain, sore eyes, muscle problems, frequent need to urinate, anorexia (decreased appetite) and fatigue.
Recommended dosage for children is 1000 IU (International Units; used for vitamins), and for adults id 2000 IU. It can go well above these numbers, but it shouldn’t go over 10.000 IU.Vitamin D is responsible for control of calcium and phosphorus levels in blood.
It is also connected to normal cellular creation and insulin secretion. To reach an acute overdose (called hypervitaminosis) it takes anywhere from several days to a few moths. It is very hard to diagnose vitamin D overdose because it is so rare.
Too much vitamin D in your blood stream can cause hypercalcemia which is actually too much calcium in your blood and that can lead to overcalcification of bones, kidneys and heart. It can cause kidney stones which can be followed by hypertension (high blood pressure).Vitamin D is created in the body through exposure to sunlight. It is synthesized in the skin.
Vitamin D and calcium are crucial for strong bones, but there’s long been confusion about how much is the right daily amount for optimal health. Get too little from your diet or through a supplement and you risk fractures and osteoporosis. Consume too much and you may develop painful kidney stones and potential kidney damage. It turns out most adults under age 70 in the U.S. and Canada should get no more than 600 international units (I.U.) of vitamin D per day, according to a comprehensive new report, which also found that adults age 19 to 50 need no more than 1,000 milligrams of daily calcium to maintain health.
A committee at the independent Institute of Medicine (IOM) examined more than 1,000 studies on vitamin D and calcium intake and found that more isn’t necessarily better. Its advice on how much is adequate varies by age and sex. The IOM recommends that most children ages 1 through 3 get 700 milligrams of calcium per day to meet their bone-health needs, and 1,000 milligrams daily is appropriate for kids age 4 through 8. Kids and teenagers between age 9 and 18 need no more than 1,300 milligrams a day. Most adults age 19 through 50 – and men until age 71 – can have their calcium needs covered by getting 1,000 milligrams a day, the IOM recommends. Starting at age 51, women need no more than 1,200 milligrams a day, and men should up their daily limit to the same when they turn 71.
In terms of vitamin D, which the body can produce when exposed to the sun’s ultraviolet rays, most people in the U.S. and Canada need no more than 600 I.U.s of it daily, unless they’re 71 or older, in which case they may need as much as 800 daily I.U.s, the report found. The IOM assumed minimal sun exposure in its calculations, a likely effect of more time spent indoors and warnings about the link to skin cancer.
The good news is many people are likely getting at least half the daily recommended calcium intake from consuming dairy products, says Dr. Sundeep Khosla, an endocrinologist and research scientist at the Mayo Clinic in Rochester, Minn., who wasn’t involved in the IOM study.
“People often don’t count up what they have in their diet,” he says, noting that each serving of milk or dairy products typically delivers between 200 and 300 milligrams of calcium. Having two glasses of milk every day, for example, or loading up on calcium-rich vegetables would get people closer to the daily recommended limit and reduce the need for high-dose supplements, Khosla says.
“Especially if you’ve had a history of kidney stones, you need to be very cautious about the amount of calcium supplementation you’re taking,” he says.
What’s more, excessive vitamin D intake can damage the kidneys and heart, according to the report.
Vitamin D controversies
Vitamin D is instrumental in helping the gut absorb calcium, and it’s received a lot of attention in the last few years as a potential weapon in the fight against cancer, diabetes, depression, heart disease and other serious diseases. But the jury is out on whether it helps prevent some of these conditions or may even raise the risk of others such as pancreatic cancer if taken at high levels, Khosla says.
“Bone health is the main one for which there’s evidence that vitamin D is helpful,” says Khosla, president of the American Society for Bone and Mineral Research. “At this point the IOM felt, and most of us would agree, you can’t really advocate vitamin D for these other issues.”
Some doctors advocate for daily doses of vitamin D in excess of 600 I.U.s, but that position may be harder to justify now that the IOM has weighed in, he says.
“What this will do is bring those people into the moderate zone the IOM is recommending,” Khosla says.
Another issue the report raises is the lack of uniform standards used by clinical laboratories to determine when blood tests show sufficient or deficient levels of vitamin D in the first place.
You cannot get too much vitamin D by sunbathing, nor is it very likely to get too much of this vitamin from food. Hypervitaminosis D occurs only if there is an excessive use of food supplements which contain this vitamin. However, treating hypervitaminosis D is not a problem.
You should just limit your intake for some period of time. Vitamin D is fat soluble, which means that it is stored in your fat cells. It may take some time until all the reserves in your body are depleted, including those in fat cells. When that happens, all the symptoms will be gone.