Can too much vitamin D be toxic? As more Americans take vitamin D supplements, there has been concern that more people could experience toxic effects from very high vitamin D levels. But a new study shows that people rarely experience harmful side effects when taking large amounts of vitamin D. Researchers analyzed information from more than 20,000 vitamin D blood tests performed on people living in Rochester, Minnesota, and the surrounding area over a 10-year period. They looked to see how many people had "high" vitamin D levels, defined as levels over 50 nanograms per milliliter. (Normal vitamin D levels are between 20 and 50 ng/mL.) About 8 percent of the people had vitamin D levels over 50 ng/mL, but 0.6 percent had even higher levels, over 80 ng/mL, and 0.2 percent had levels over 100 ng/mL. The researchers also found that the proportion of people with high vitamin D levels increased considerably during the study period — from 9 per 100,000 people in 2002 to 233 per 100,000 people in 2011.
This spike is likely due to an increase in people taking vitamin D supplements, either because a doctor prescribed them or because they decided on their own to take them, the researchers said. Despite this increase, the people in the study rarely experienced hypercalcemia, or high blood calcium levels that can occur as a result of high vitamin D levels. The condition can cause weakness, vomiting and kidney problems, and is the main side effect of high vitamin D levels. In fact, there was no link between people's vitamin D levels and their blood calcium levels. [9 Good Sources of Disease-Fighter Vitamin D] "We found that, even in those with high levels of vitamin D over 50 ng/mL, there was not an increased risk of hypercalcemia, or elevated serum calcium, with increasing levels of vitamin D," study co-author Dr. Thomas D. Thacher, a family medicine expert at Mayo Clinic, said in a statement. The study identified just four cases over the 10-year period of people who had hypercalcemia associated with high vitamin D levels, and three of those were mild cases in which people did not have symptoms.
(In those three cases, the condition was revealed only by the blood test.) There was just one case of true vitamin D toxicity, in a 51-year-old woman who had vitamin D levels of 364 ng/mL. The woman had taken 50,000 international units (IU) of vitamin D per day for three months, along with calcium supplements, and went to the doctor with weight loss, vomiting and confusion. (The recommended upper limit for vitamin D supplementation is 4,000 IU per day.) The woman turned out to have kidney damage. Doctors should ask their patients about vitamin D supplements that they are taking, because people can buy very high doses — as much as 50,000 IU — over the counter, Thacher said. The study was published in the May issue of the journal Mayo Clinic Proceedings. Vitamins and Supplements May Lead to Earlier Death 5 Key Nutrients Women Need As They Age 9 Healthy Habits You Can Do in 1 Minute (Or Less) Copyright 2015 LiveScience, a Purch company. This material may not be published, broadcast, rewritten or redistributed.
Some individuals subscribe to the thought that, “if a little is a good thing, a lot is better.” That may be true in some activities and some circumstances when it comes to your health, but with optimal vitamin intake and supplementation that’s simply not true. According to Medscape, the majority of Americans consider vitamins safe, and that belief alone can increase the likelihood of taking too many, as there is no perceived risk in the minds of many people. The truth is, too much of certain vitamins can lead to a vitamin overdose, which can be dangerous and, in some cases, life threatening. That is certainly not true with many vitamins – you’re safe with a multivitamin that covers about 100% of the Daily Value (DV) for all vitamins and minerals. Daily Values are the levels of vitamins and minerals set by the Food and Drug Administration for the general population. But there are some nutrients to be careful with… Recently, there’s been a lot of buzz about vitamin D deficiency and the problems vitamin D deficiency can cause in individuals, and for good reason.
Vitamin D, known as “the sunshine vitamin,” is primarily responsible for the regulation of calcium and phosphorus in the bones.* Without vitamin D, you’d be a softy – quite literally! Coupled with a lack of calcium intake and physical activity, your bones would likely become soft and weak over time, increasing the risk of osteoporosis, discomfort in the bones, and even a greater risk of broken bones! But, pay attention – while vitamin D overdose is extremely rare, there is such a thing as too much. Too much vitamin D can lead to a vitamin overdose and can cause permanent damage to your kidneys and heart. Vitamin D overdose symptoms can lead to bothersome health issues, although perhaps temporary, include nausea, vomiting, alternating constipation and diarrhea. Sometimes vitamin D overdose can even result in dangerous heart rhythm abnormalities. In addition, a vitamin D overdose in pregnancy has been shown to increase the potential of mental retardation in babies.
Though the recommended daily requirement of vitamin D is around 1,000 IU, many doctors believe this is too low and regularly prescribe more to those who are vitamin D deficient. So how much is too much? It has been shown that taking 40,000 IU of vitamin D in infants and 50,000 IU in adults for several months can cause toxicity. Make no mistake, that is a lot of vitamin D! The best way to determine the appropriate amount of vitamin D for you and avoid overdose is to avoid so-called mega-dosing, consult your own healthcare professional, and have your levels tested. If you are pregnant, make sure that you follow your healthcare professional’s guidelines for safe vitamin D supplementation to avoid a vitamin D overdose. We hear a lot about B vitamins, a group of 8 distinct vitamins, each responsible for aiding various functions in the body. The functions of the vitamin B group range from supporting the rate of metabolism, promotion of healthy skin and hair, as well as memory support.* Since the vitamin B group is responsible for all of that good stuff, can you really get too much resulting in a vitamin B overdose?
With some of the B vitamins, unfortunately, yes. In fact, a vitamin B6 overdose can lead to nerve toxicity, while B3 can lead to nausea, jaundice, and liver toxicity. Too much folic acid, too, can mask the symptoms of a B12 deficiency. So how much is too much? Typically, 300 mg of B6 is scary territory, while 2000 mg of B3 is risky. For folate, the Institute of Medicine recommends adult men and women not consume more than 1000 mg per day. In order to avoid a vitamin B overdose, make sure you consult your healthcare professional. Vitamin A supplementation may enable you to delay getting reading glasses since it supports the function of the human eye, but a severe vitamin A overdose can actually cause death.* Normally, a vitamin A overdose progresses slowly as it accumulates in the body, particularly since it is a fat-soluble vitamin and is stored in your fat cells. The initial signs of a vitamin A overdose may emerge as rather benign health issues: dry, rough skin, cracked lips, and hair loss.
Latter symptoms of vitamin A overdose may include irritability, headache, high level of liver enzyme in blood, and liver disease. In addition to a slow progressing vitamin A overdose, there is such a thing as an acute vitamin A overdose. This is a far more serious type of vitamin overdose with symptoms ranging from vomiting, high pressure in the brain, and even death. The vitamin A recommended daily dose for children 4 to 8 years old is 3000 IU and for adults is 10,000 IU. Staying within these limits is advised, but it is best to check with your healthcare professional to determine what is best for you. Probably one the most widely known and one of the most dangerous vitamin overdoses, particularly for children, is an iron overdose. While iron is necessary for red blood cells and the prevention of anemia, an iron overdose can lead to death, and is actually the leading cause of fatal poisoning in children younger than 5. This is the major reason why we don’t put iron in our gummies.
The best source of iron is from foods like spinach, sweet potatoes, whole wheat bread, strawberries, and eggs. If your healthcare professional tells you that you or your child still need more iron, using liquid iron with a dropper will allow you to control the iron levels and has no appeal to kids as a treat. The recommended daily requirement of iron for adults varies depending on age. The same goes for the recommended daily requirement for children. Depending on the severity of the health issues, a vitamin overdose may not be cause for immediate alarm. If the health issues aren’t life threatening or life altering, simply reduce or discontinue the use of a daily multivitamin. However, if you have any concerns for you or your family member, contact a healthcare professional sooner than later. Most vitamin overdose problems occur in children under six years of age. If acute life threatening symptoms appear, seek medical assistance immediately. Storage of supplements is also important for every household.