Mayo Clinic Q And A: How Much Vitamin D Do I Need
DEAR MAYO CLINIC: I have heard different recommendations from different sources regarding vitamin D. One doctor told my husband that everyone living in the Northern Hemisphere should take a vitamin D supplement every day, even in the summer. What do you recommend?
ANSWER: Understanding how much vitamin D you need can be confusing because there are different recommendations about how much vitamin D adults should get. Using the recommendations that fall on the low end, many adults dont get the amount of vitamin D they should. Because few foods contain vitamin D naturally, eating foods fortified with vitamin D and taking a supplement may be beneficial.
Vitamin D is important because it helps your body sustain normal levels of calcium and phosphorus. Because it works as a key that allows your body to absorb calcium, vitamin D plays a critical role in forming and maintaining healthy bones. It also helps keep your muscles, nerves and immune system healthy.
Research suggests that consistently getting enough vitamin D can significantly lower the risk for the bone-thinning disease osteoporosis. Low vitamin D also is associated with falls, multiple sclerosis, rheumatoid arthritis, chronic pain, diabetes, high blood pressure, cardiovascular disease and some cancers. However, an association does not mean low vitamin D causes these conditions, or that taking a vitamin D supplement will adequately prevent or treat them.
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The Move Away From International Units
Starting in 2021, the International Unit will no longer be the only strength listed on vitamin D supplements. In fact, it may not be listed at all.
New dietary supplement labeling requirements from the FDA will go into full effect by January 2021. Among other things, they will require the strength of vitamin A, D and E to be listed as a metric measure .
“In addition to changing some DVs , the proposed rule would change the units used to declare vitamins A, E, and D from international units, or I.U. to a metric measure, milligrams or micrograms, and also would include the absolute amounts in milligrams or micrograms of vitamins and minerals, in addition to the % DV, on the label.” Federal Register / Vol. 81, No. 103 / Friday, May 27, 2016
Many manufacturers have already started following these new requirements, by listing both the IU strength and the metric strength on their labels. Here is one example:
Hopefully, manufacturers will list both the International Units and the metric strength to assist individuals in finding the appropriate product.
However, there certainly may be situations where you need to convert between one or the other.
Fortunately, the conversion is easy.
Will Vitamin D Prevent Dementia Cancer And/or Premature Death
Several studies have identified an association between vitamin D deficiency and diagnoses such as Alzheimers disease and cancer. In other words, people with these conditions tend to have low vitamin D blood levels.
But an association isnt the same thing as causation, so its not yet known whether vitamin D deficiency causes these diseases. Its also not yet known whether taking vitamin D supplements will reduce ones chance of developing these diseases.
To date, most randomized studies of vitamin D to improve health outcomes have been negative.
Although its possible that low vitamin D levels might be a factor in developing certain diseases, its probably a small effect. Cancer and Alzheimers, after all, generally seem to be the result of lots of little factors genetics, epigenetics, stress, immune function, nutrition, inflammation, toxins interacting over time.
In 2010, the Institute of Medicine concluded: This thorough review found that information about the health benefits of vitamin D supplementation beyond bone healthbenefits often reported in the mediawere from studies that provided often mixed and inconclusive results and could not be considered reliable.
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What Is Vitamin D And Why Is It Important
Vitamin D belongs to the family of fat-soluble vitamins, which include vitamins A, D, E and K. These vitamins are absorbed well with fat and are stored in the liver and fatty tissues.
There are two main forms of vitamin D in the diet:
- Vitamin D2 : Found in plant foods like mushrooms.
- Vitamin D3 : Found in animal foods like salmon, cod and egg yolks.
However, sunlight is the best natural source of vitamin D3. The UV rays from sunlight convert cholesterol in your skin into vitamin D3 .
Before your body can use dietary vitamin D, it must be activated through a series of steps .
First, the liver converts dietary vitamin D into the storage form of vitamin D. This is the form that is measured in blood tests. Later, the storage form is converted by the kidneys to the active form of vitamin D thats used by the body .
Interestingly, D3 is twice as effective at raising blood levels of vitamin D as vitamin D2 .
The main role of vitamin D in the body is to manage blood levels of calcium and phosphorus. These minerals are important for healthy bones .
Research also shows that vitamin D aids your immune system and may reduce your risk of heart disease and certain cancers .
A low blood level of vitamin D is linked to a greater risk of fractures and falls, heart disease, multiple sclerosis, several cancers and even death (
For instance, an analysis of five studies examined the link between vitamin D blood levels and colorectal cancer .
Can Taking Too Much Vitamin D3 Hurt You
Yes, taking too much vitamin D3 can cause issues. Vitamin D toxicity can lead to an abnormally high blood calcium level, which can cause nausea, vomiting, constipation, poor appetite, and weight loss.
It can also lead to kidney stones and other kidney problems. If you take too much vitamin D it can also damage your liver. Therefore, it’s important to speak with your doctor if you’re thinking about taking vitamin D supplements, especially if you take other medications.
While vitamin D is essential for our health, it’s possible to have too much of a good thing. Too much vitamin D can lead to serious health problems, so it’s important to speak with your doctor before taking any supplements.
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Is 50 000 Units Of Vitamin D A Lot
When provided for 12 months, vitamin D3 treatment was safe and effective in reversing statin sensitivity in individuals with vitamin D insufficiency. Serum vitamin D levels seldom surpassed 100 ng/mL, and there was no significant change in serum calcium or eGFR. These data suggest that high-dose vitamin D supplementation is safe and may be effective in restoring cholesterol metabolism in some hypercholesterolemic patients on statins.
Vitamin D Deficiency: Symptoms Treatment And Prevention
Experts only recommend testing only for people at high risk for vitamin D deficiency, like those populations at high risk for developing low levels, or those with signs suggestive of a vitamin D problem . Screening tests for vitamin D deficiency are not recommended .
The majority of patients with low vitamin D dont have symptoms. But for severe and prolonged vitamin D deficiencies, some common signs include :
- Muscle weakness
- Bone pain
The reference ranges for vitamin D blood levels are not well established. According to the NIHs Office of Dietary Supplements and the Institute of Medicine , reference ranges are as follows :
Suppose you have low vitamin D levels or vitamin D deficiency. In that case, your healthcare provider may suggest increasing your dietary intake through food products, sun exposure, or supplements, such as high-dose vitamin D 5000 IU pills.
Work with your doctor to determine if you need a vitamin supplement and how much of it.
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Tolerable Upper Intake Level
The tolerable upper intake level, or UL, is the âmaximum amount of a nutrient that is safeâ for the general population to get each day on a regular basis. Above this amount, the health risks increase the greater the excess intake, the greater the health risks, according to the National Institutes of Health .
The National Academy of Medicine has set the UL for vitamin D at 4,000 IU, or 100 mcg, per day for all adults. Taking 50,000 IU of vitamin D each week, divided among seven days, would give you 7,143 IU each day, which is nearly double the UL.
Is It Ok To Take Vitamin D3 Every Day
Yes, it is absolutely fine to take vitamin D3 every day. In fact, many doctors recommend taking a daily supplement of vitamin D, especially during the winter months when we don’t get as much sunlight.
Vitamin D is a fat-soluble vitamin, which means it can be stored in your body for long periods of time. This is why you don’t need to take it every day. However, if you are deficient, taking a supplement daily will help increase your levels back to normal.
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What Should You Do
These conflicting recommendations and data pose a dilemma for the consumer. A daily intake of 7,000 IU is highly unlikely to cause vitamin D toxicity and very unlikely to cause other problems. However, there’s no way to be sure.
If you think you may be deficient in vitamin D, see your doctor for a âblood testâ. Get her expert advice on the right blood level. If testing shows you are below this level, then follow your doctor’s recommendation for how much vitamin D to take each day.
Vitamin D Can Fight Inflammation
Vitamin D is beneficial to the immune system because it helps regulate the production of cytokines. Cytokines are proteins that are used by the immune system to communicate with other cells, and when they are produced in the wrong amounts or at the wrong time, they can cause inflammation.
Vitamin D can also help reduce the risk of infections by promoting the production of white blood cells and increasing the efficiency of T-cells. A lack of Vitamin D has been linked to an increased susceptibility to infection, so maintaining healthy levels might help keep you from getting sick.
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How Does Vitamin D3 Work
Vitamin D is a fat-soluble vitamin that may only be found in a few foods, added to others, and obtained as a supplement. It’s also produced naturally by the body when sunlight strikes the skin, which stimulates vitamin D synthesis.
Vitamin D is biologically inactive unless two hydroxylations occur in the body after absorption. The first is carried out in the liver, where vitamin D is converted to 25-hydroxyvitamin D .
Calcitriol is a calcium and phosphate regulator that circulates in the blood and works to maintain bone formation and other physiological processes. Vitamin D sufficiency is defined as serum 25D levels of at least 30 ng/mL .
The majority of vitamin D is obtained from sunlight, although the quantity of sun exposure required to maintain sufficient amounts varies based on a person’s age, skin color, season, latitude, time of day, clothing habits, and usage of sunscreen.
People who don’t get enough sun exposure need to get their vitamin D from foods or supplements in order to achieve and maintain sufficient serum 25D levels.
Vitamin D Units To Microgram And Milligram Conversion
The conversion between Vitamin D units and micrograms is easy:
From Micrograms to IU:
- 1 microgram equals 40 IU
Similarly, going from IU to mcg:
- 1 IU equals 0.025 mcg
The most common strengths you will see are:
- Vitamin D 400 IU = 10 mcg
- Vitamin D 1,000 IU = 25 mcg
- Vitamin D 2,000 IU= 50 mcg
- Vitamin D 5,000 IU = 125 mcg
- Vitamin D 10,000 IU = 250 mcg
- Vitamin D 50,000 IU = 1,250 mcg
So, the specific answer to your question, “400 units of Vitamin D is how many micrograms?”, the answer is 10 mcg.
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How Much Vitamin D Is Too Much
Since relatively little is known about how vitamin D toxicity works, its hard to define an exact threshold for safe or toxic vitamin D intake .
According to the National Academy of Medicine, formerly known as the Institute of Medicine, 4,000 IU is the safe upper level of daily vitamin D intake. However, doses up to 10,000 IU have not been shown to cause toxicity in healthy individuals (
Hypercalcemia caused by regularly taking high amounts of vitamin D supplements may take a few months to resolve. This is because vitamin D accumulates in body fat and is released into the blood slowly .
Treating vitamin D intoxication includes avoiding sun exposure and eliminating all dietary and supplemental vitamin D.
A doctor may also correct your calcium levels with increased salt and fluids, often by intravenous saline.
The main consequence of vitamin D toxicity is hypercalcemia, with symptoms including nausea, vomiting, weakness, and kidney failure. Treatment involves limiting all vitamin D intake and sun exposure.
So How Much Vitamin D Is Actually Too Much
“Interestingly 10,000 I.U. of vitamin D per day is considered a science-backed Tolerable Upper Intake Level from top vitamin D researchers who have actually studied vitamin D toxicity for decades,” says Ferira.
To be clear, the U.L. is not the toxic level. Instead, the U.L. is the highest amount of a nutrient the general population can take that likely doesn’t have a risk of adverse health effects. “That’s an important call-out: general population,” Ferira continues. “We’re individuals, and the collective science plus your health care provider may determine you personally need less or more than the ‘average’ person.” In fact, some people may even need more than 10,000 I.U. of vitamin D3 per day to reach the desired 50 ng/mL range.*
Gallo seconds the advice: “In cases where an individual may be at risk for deficiency, higher intake may be warrantedand this decision should be made in consultation with a health care professional who can monitor for any signs or risks of toxicity,” she says.
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Might Prevent Certain Types Of Cancer
Vitamin D3 can assist decrease the chance of developing particular types of cancer. Epidemiological studies have shown that people who reside in southern/equatorial regions and are more exposed to the sun have a lower risk of some malignancies.
Vitamin D has been linked to cancer in numerous studies. Vitamin D aids in the repair and regeneration of cells, which might slow the growth of cancerous tumors, stimulate the death of cells that have been damaged by cancer, and decrease blood vessel formation in tumors.
Can U Get Enough Vitamin D From The Sun
Regular sun exposure is the most natural way to get enough vitamin D. To maintain healthy blood levels, aim to get 1030 minutes of midday sunlight, several times per week. People with darker skin may need a little more than this. Your exposure time should depend on how sensitive your skin is to sunlight.
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Precautions Regarding Vitamin D Intake
If you notice signs of vitamin D side effects and youre at risk for experiencing vitamin D toxicity due to taking more than 300,000 IU in the past 24 hours or more than 10,000 IU per day for the past several months then stop taking vitamin D and visit your doctor right away for a blood test. Your doctor will test you for hypercalcemia and also discuss any symptoms youre having.
While taking too much vitamin D can be dangerous in some instances, keep in mind that getting too little vitamin D is also problematic. Your goal should be is to strike a balance and get the amount of vitamin D your body needs without taking excessive quantities.
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Cholecalciferol 125 Mcg Capsule
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Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and phosphorus. Having the right amount of vitamin D, calcium, and phosphorus is important for building and keeping strong bones. Vitamin D is used to treat and prevent bone disorders . Vitamin D is made by the body when skin is exposed to sunlight. Sunscreen, protective clothing, limited exposure to sunlight, dark skin, and age may prevent getting enough vitamin D from the sun.
Vitamin D with calcium is used to treat or prevent bone loss . Vitamin D is also used with other medications to treat low levels of calcium or phosphate caused by certain disorders . It may be used in kidney disease to keep calcium levels normal and allow normal bone growth. Vitamin D drops are given to breast-fed infants because breast milk usually has low levels of vitamin D.
Take vitamin D by mouth as directed. Vitamin D is best absorbed when taken after a meal but may be taken with or without food. Alfacalcidol is usually taken with food. Follow all directions on the product package. If you have any questions, ask your doctor or pharmacist.
If your doctor has prescribed this medication, take as directed by your doctor. Your dosage is based on your medical condition, amount of sun exposure, diet, age, and response to treatment.
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Why Should I Supplement With Vitamin D3
Customer: To me, there’s nothing better than being outside on a really nice day. Whether I’m working in my garden or taking a walk with my family, we all love the outdoors. But during my last checkup, the doctor noticed that I wasn’t getting enough vitamin D.
Michael A. Smith, MD: From your brain to your heart, your bones to your immune system, vitamin D affects nearly every cell in your body and is critical for optimal health. Even if you spend a lot of time outdoors, your body may not be producing enough of this important vitamin. In fact, studies show that people are really low in vitamin Dand that’s why doctors are recommending it to their patients more than ever.
Customer: So, my body needs more vitamin D, but there are all these different doses and options. How can I decide which is best for me?
Michael A. Smith, MD: Like all of our products, Life Extensions Vitamin D3 is made with the highest quality standards. We recommend taking 5,000 international units a day, but we offer doses ranging from 1,000 to 7,000 units depending on your vitamin D blood level. Be sure to check with your doctor to see which one is right for you. We also offer Vitamins D and K with Sea-Iodine for a complete vitamin D formulation.
Customer: Three weeks in, and vitamin D has really made an impact on my whole life. I have more energy and overall, I feel for lack of a better wordsunnier.