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How Much Vitamin D Should An Adult Take Daily

Taking Vitamin D Safely

Should Adults and Kids Take Vitamin D Daily?

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Each 1-A-Day vitamin D supplement contains 10 micrograms of vitamin D. This is equivalent to 400 international units of vitamin D. This is the daily amount recommended for the general population by government for general health and in particular to protect bone and muscle health.

If your GP has recommended that you take a different amount of vitamin D, you should follow your GPs advice.

Do not exceed the recommended dose equivalent to 400 international units). This is a safe level of intake, designed to meet your nutritional needs. Taking more is not currently recommended.

For most people taking up to 100 micrograms equivalent to 4,000 international units) per day is considered safe. In a few people, taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body . This can weaken the bones and damage the kidneys and the heart. NHS.UK has more information about vitamin D, including advice on intakes.

While some medications may interact with high doses of vitamin D, there are no issues associated with the 10 microgram vitamin D supplement. They are intended to supplement the diet and should not be substituted for a varied diet.

The Possible Link Between Vitamin D And Chronic Conditions

Generally, research on the role vitamin D may play in disease prevention and management is murky. Particularly with regard to the benefits of taking supplements, most of the studies have been observational or done on small groups . Until recent years, there has been a lack of large randomized, controlled trials, which are the gold standard for medical research because such studies point to cause-and-effect relationships between factors. The data now coming in from such trials fails to back up previous claims about the benefits of vitamin D supplementation.

But one thing is for sure: The scientific communitys interest in vitamin D clearly isnt waning. Heres what some of the latest research suggests about how the vitamin may affect certain chronic conditions.

Bone Health As mentioned, vitamin D helps in the absorption of calcium in the gut. So its no surprise that vitamin D supplements have long been recommended for preserving bone health. However, recent research has found that they dont live up to the hype. A review of more than 81 clinical trials published in November 2018 in TheLancet Diabetes and Endocrinology found that vitamin D supplements dont prevent fractures or falls, or affect bone mineral density to a degree that is clinically meaningful.

What About Sun Exposure

The DRIs for vitamin D are set based on the assumption of minimal sun exposure. This was necessary because of public health concerns about skin cancer due to ultraviolet radiation from the sun. Currently, there is a lack of information about whether sun exposure may be experienced without increasing risk of cancer.

Many people meet at least some of their vitamin D needs through exposure to sunlight. However, season, time of day, cloud cover, smog, skin pigmentation, and sunscreen use are all factors that can affect the amount of ultraviolet radiation received and thus vitamin D synthesis.

The DRI values have been set at levels that ensure that sun exposure is not necessary in order to obtain enough vitamin D.

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Q: Should People Consider Vitamin D Supplements

A: If the level of vitamin D in your blood is less than 20 nanograms per milliliter, your doctor may recommend taking a supplement. Many women already take calcium and vitamin D supplements together for bone health because vitamin D can help in calcium absorption, and they work best when taken together. Ask your doctor if supplements are right for you.

Can You Get Enough Vitamin D In The Sun Only

Your Vitamin D Requirements are VASTLY Higher Than You Think

Some people will be able to get enough vitamin D from the sun. However, it depends on where they live in the world, the time of year, the time of day, and the color of their skin.

People living near the equator get a lot of sun. In the Northern Hemisphere, a person may not be getting enough vitamin D from the sun during the winter.

The sun usually rises between 11:00 am and 3:00 pm In summer, one does not need to stay in the sun too long to make enough vitamin D.

The amount of melanin a persons skin contains affects how much vitamin D they can produce. A small amount of melanin leads to light, unprotected skin, and harmful ultraviolet radiation.

People with a lot of melanin on their skin are better protected from the sun, but it takes longer to make vitamin D. In the United States, the Centers for Disease Control and Prevention found that many Mexican, American, and non-Spanish blacks are more likely to be deficient in vitamin D.

These various factors make it difficult to recommend how much sun a person should get to make the vitamin D his body needs.

Vitamin D Council provides some examples:

  • At noon during the summer in Miami, a person with a medium skin tone will need to expose one-quarter of his or her skin to sunlight for six minutes.
  • At noon during the summer in Boston, someone with a dark skin tone will have to expose one-quarter of their skin to sunlight for two hours.

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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.

How Can I Know If I Am Vitamin D3 Deficient

Since there are two kinds of vitamin D, you need to have a blood test for both to know what dosage of vitamin D3 is appropriate for you. If you have low levels of vitamin D3, the storage form of the vitamin, then you definitely need to take more vitamin D3, up to 5,000 IU per day for up to two weeks, and then 1,000 to 2,000 IU per day as a maintenance dose thereafter. This is what is needed if the problem is not getting enough sun.

If you body has a problem converting vitamin D3 to D2, however, and your levels of D3 are high but your levels of D2 are low, then you need to speak with a nutritionally oriented doctor or a nutrition specialist about the full range of supplements that will help your body use its daily dosage of vitamin D3 effectively in making the active form of the vitamin, D2. Be sure you have both tests to make sure you are getting all the vitamin D you really need.

Selected Sources:

Laaksi I, Ruohola JP, Mattila V, Auvinen A, Ylikomi T, Pihlajamäki H. Vitamin D supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young Finnish men. J. Infect Dis. 2010 Sep 1 202:809-14.

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Whats The Recommended Intake

The Institute of Medicine has developed a set of reference values for specific nutrient intake levels, including for vitamin C.

One set of guidelines is known as the Recommended Dietary Allowance and considers average daily nutrient intake from both foods and supplements.

RDA recommendations for specific gender and age groups should meet the nutrient needs of 9798% of healthy individuals (

Here are the RDAs for vitamin C :

Life stage
Adult women 75 mg
Adult men 90 mg
Pregnant women 85 mg
Breastfeeding women 120 mg

In addition to the RDA recommendations for vitamin C, the Food and Drug Administration has issued a recommended Daily Value .

The DV was developed for food and supplement labels. It helps you determine the percentage of nutrients in a single serving of food, compared with the daily requirements. On food labels, this is displayed as %DV .

Currently, the recommended DV for vitamin C for adults and children aged 4 and above is 60 mg regardless of gender. However, in January 2020, this will increase to 90 mg .


The RDA for Vitamin C ranges from 1575 mg for children, 75 mg for adult women, 90 mg for adult men, and 85120 mg for women who are pregnant or breastfeeding.

Vitamin C is essential for overall health and wellness, and the nutrient may particularly benefit certain conditions.

The vitamin is especially helpful for immune health, as it supports your immune systems cellular function .

Did The Iom Report Make Recommendations With Respect To Serum Vitamin D Levels

How Much Vitamin D Should I Take

Serum concentration of 25-hydroxy-vitamin-D D) is the best indicator of vitamin D status. It reflects total vitamin D input – from food, supplements, and sun exposure.

There is considerable discussion surrounding the serum concentrations of 25D associated with optimal health, and cut points have not been developed by a scientific consensus process.

However, the IOM expert committee stated that its review of the data suggests that, relative to bone health:

  • People are at risk of vitamin D deficiency at serum 25D concentrations < 30 nmol/L. Some are potentially at risk for inadequacy at levels ranging from 3050 nmol/L.
  • Practically all people are sufficient at levels 50 nmol/L
  • There may be reason for concern at serum concentrations > 125 nmol/L

The IOM expert committee encouraged the development of evidence-based cut points for serum vitamin D measures relative to deficiency as well as excess.

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Does Being A Man Or A Woman Affect How Much Vitamin D You Need

Yes and no. Body size is more influential than sex when it comes to vitamin D intake recommendations, Foroutan says. On average, men weigh more than women. However, the relative amount of body fat an individual has may be more pertinent, since vitamin D is stored in body fat.

A study published online in November 2014 in PLoS One aimed to analyze the effect that body mass index may have on vitamin D dosing targets. Findings suggested that participants who were obese needed 2 to 3 times more vitamin D than their normal-weight counterparts.

But men and women are at different risks for various chronic conditions, which means adjusting your vitamin D target may be helpful for managing symptoms or delaying disease progression.

For example, women may be more likely than men to develop both thyroid disease, per the Department of Health and Human Services Office on Womens Health, and osteoporosis, and a vitamin D deficiency is associated with both, other research suggests. If you live with a chronic disease that is associated with your sex, your doctor may factor in vitamin D as part of your personal management plan.

What Tests Can Reveal

The most common way to measure vitamin D levels is with a blood test for 25D , but its not perfect. There are many different versions of the test, and the results can vary, says Mark Moyad, M.D., director of complementary and alternative medicine at the University of Michigan Medical Center, who specializes in studying vitamins, minerals, and supplements. You can get different results from different labs and even after multiple tests at the same lab.

Many of us in geriatrics, for better or worse, do screen and do treat vitamin D deficiencies, says Veronica Rivera, M.D., an assistant professor of geriatrics and palliative medicine at the Icahn School of Medicine at Mount Sinai. She admits that the evidence about testing and treatment is unclear. If Im doing yearly labs on someone, I may add it in. If theyre having falls, I may check it. If someone has osteoporosis or osteopenia, I would definitely screen, she says. The evidence is still conflicting, but I think the safe approach is to keep everyone at sufficient levels and to make it easy.

Another confounding factor is that normal D levels may differ depending on skin color. We make vitamin D when our skin is exposed to sunlight. Darker skin makes it harder to synthesize the vitamin, leading to lower levels, but researchers are still trying to understand the health implications of that and the need for supplements.

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Can You Get Enough Vitamin D From The Sun Alone

Some people will be able to get enough vitamin D just from sunlight. However, it depends on where in the world they live, the time of year, the time of day, and their skin color.

People who live nearer the equator get more sun exposure. In the Northern Hemisphere, a person may not get sufficient vitamin D from sunlight during the winter.

The sun is usually strongest between 11:00 a.m. and 3:00 p.m. In the summer, a person does not need to be out in the sun for very long during this period to make enough vitamin D.

The amount of melanin a persons skin contains affects how much vitamin D they can make. Less melanin results in lighter skin, which does not protect as well against harmful ultraviolet rays.

People with more melanin in their skin have better protection from the sun, but take longer to make vitamin D. In the United States, the Centers for Disease Control and Prevention found that Mexican-Americans and non-Hispanic black people are more likely to have vitamin D deficiency.

These varied factors make it difficult to recommend how much sunlight a person should get to make the vitamin D that their body needs.

The Vitamin D Council gives some examples:

  • At noon during summer in Miami, someone with a medium skin tone would need to expose one-quarter of their skin to sunlight for 6 minutes.
  • At noon during summer in Boston, someone with a darker skin tone would need to expose one-quarter of their skin to sunlight for 2 hours.
  • egg yolk
  • beef liver

Am I Taking Too Much Vitamin D

The Sunshine Vitamin: Why Women Need a Vitamin D Supplement

Even though taking vitamin D has many health benefits, its possible to take too much. Vitamin D toxicity, or hypervitaminosis D, can cause a buildup of calcium in the blood and result in bone pain, nausea, vomiting, or kidney problems.

Here is a list of the more common side effects that someone might experience from taking too much vitamin D:

  • Fatigue
  • Nausea
  • Weakness

Some medications may interact with vitamin D. Steroids may interfere with how the body metabolizes the vitamin. The cholesterol-lowering drug cholestyramine and weight-loss drug orlistat can hinder the bodys ability to absorb vitamin D. Some medications can also increase vitamin D levels.

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The Right Foods Supplements

Vitamin D is called the sunshine vitamin since it is made in the skin after exposure to sun. The same UVB rays that cause a sunburn also make vitamin D. Sunscreen, darker skin pigmentation, clothing and reduced daylight in winter diminish the skins ability to make vitamin D. The people who experience the biggest seasonal swings in vitamin D levels are fair-skinned individuals living in the northern regions of the United States and at higher latitudes around the globe where there is very little daylight in winter.

But those most at risk for low vitamin D levels are people of color and people living at higher latitudes. Dark-skinned individuals are more likely than fair-skinned individuals to be low for vitamin D year-round because the darker skin blocks the UVB rays from producing vitamin D. But even in dark-skinned individuals, vitamin D is lowest in the winter.

In the winter, in addition to high vitamin D food, adults should take additional vitamin D from foods or supplements to get at least 600 IU per day of vitamin D. People who have dark skin or avoid sunshine should eat more vitamin D year-round.

Just Right: How Much Vitamin D Is Enough

For many years, various organizations and studies have said you can get too much vitamin D while others say the opposite. Fortunately, clinical trials could provide answers to this controversial question soon.

There is little debate over the role of vitamin D and calcium in bone health, but the question of whether much higher intakes of vitamin D could have a host of nonskeletal benefits remains hotly debated. New studies linking vitamin D deficiency to nonskeletal problems are popping up with great frequency, but correlation is not causation, and most meta-analyses have not found evidence to bolster claims of wide-ranging benefits.

We are at a crossroads in terms of vitamin D research, says JoAnn Manson, MD, DrPH, a professor at Harvard Medical School who served on a recent Institute of Medicine task force on reference intakes for vitamin D. We have numerous observational studies suggesting associations between low vitamin D levels and increased risk of myriad diseases, but we dont yet know whether there is a cause and effect relationship. We do know that vitamin D deficiency is a health problem associated with bone disorders. Th e real issue is whether you have greater health benefits from exceeding, rather than meeting, the recommended dietary allowance for vitamin D. We dont yet know that giving vitamin D supplementation will lower the risk of cardiovascular disease, cancer, diabetes, cognitive decline, depression, and a host of other diseases.

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