What Does Vitamin D Actually Do In My Body
Vitamin D is important for a huge number of functions in the body, from supporting strong and healthy bones to maintaining your immune system.
Most of your bodys Vitamin D comes from getting enough sunlight on your skin. For many people, this is a challenge, which is why new Government guidelines recommend a daily Vitamin D3 supplement.
It has also been shown to support the immune system. So taking Vitamin D during the winter months, when you may be more likely to feel under the weather, could help support your immune system, which is integral in fighting off bugs.
Vitamin D And Your Health: Breaking Old Rules Raising New Hopes
Vitamin D was discovered in 1920, culminating the long search for a way to cure rickets, a painful childhood bone disease. Within a decade, the fortification of foods with vitamin D was under way, and rickets became rare in the United States. But solving the problem of rickets was only the beginning of research into vitamin D. Research results suggest that vitamin D may have a role in other aspects of human health.
How Fast Can You Raise Your Vitamin D Levels
Various studies have estimated that it takes up to 24 hours for vitamin D3 supplements to increase vitamin D levels in the blood.
Is Vitamin D Leaking Out of Your System?
Instead of being carried through your bodys wastewater, the vitamin will cling to your body fat for later use, which can compound the effects of daily overdose.
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What Happens If I Take Too Much Vitamin D
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.
If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.
Do not take more than 100 micrograms of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years.
Children aged 1 to 10 years should not have more than 50 micrograms a day. Infants under 12 months should not have more than 25 micrograms a day.
Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor.
If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.
You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you’re out in the sun for long periods to reduce the risk of skin damage and skin cancer.
Page last reviewed: 03 August 2020 Next review due: 03 August 2023
Is Vitamin D3 Better Than Vitamin D2
Studies show that Vitamin D3 is far more important for our health than Vitamin D2. So either choose a Vitamin D3 supplement, or one which contains optimal levels of both forms. Vitamin D2 on its own is not enough.
Experts used to think that vitamins D2 and D3 were of equal importance for human health. But this was based on outdated studies of rickets in children. These days, we know lots more about Vitamin D. And it is clear that D3 is far more important and more effective for our health and wellbeing.
We need to look at how the body absorbs Vitamin D to understand why Vitamin D3 is more important. There are lots of biological processes involved. A specific enzyme in the liver helps Vitamin D3 metabolise into the bioactive form of Vitamin D. This process takes much longer with Vitamin D2.
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Genomic Effect Of Vitamin D
Figure 3.
The structure of the Vitamin D receptor .
After active vitamin D crosses the target cell membrane, it interacts with the ligand-binding domain of its own receptor in the cytoplasm of the cell. Vitamin D is embedded in the ligand-binding domain, and subsequently, in the H12 alpha-helix H12 region, which is located at the end of the ligand binding part . This critical conformational change of AF-2 facilitates the binding of co-activators in later stages . In the next step, vitamin D-bound VDR binds to RXR to form a VDR/RXR heterodimer structure that binds to cognate VDR elements in the promoter region in the target genes with a high affinity to initiate gene activation or inhibition. There are many gene-specific VDREs associated with bone metabolism, xenobiotic detoxification, drug resistance, cell growth and differentiation, angiogenesis, mammalian hair growth cycle, lipid synthesis regulation, apoptosis, and immune functions, suggesting that vitamin D has numerous regulatory roles in various organs or tissues in the body .
Should You Worry If You Store Vitamin D In Your Body
There has been a lot of talk on the internet from people concerned that they are ‘Storing’ vitamin d and what problems this might cause. Now, Im not sure where people have got the idea that storing vitamin d is something that is worrisome or something harmful, but let me set the record straight that you should not worry if you store vitamin d. Vitamin d is a FAT SOLUBLE vitamin and you do not excrete it through the sweat, urine or stool as you would if it were a Water Soluble vitamin. Vitamins and minerals such as the B vitamins, magnesium and Vitamin C Supplements must be taken on a daily basis because they get excreted if you do not use them in a short period of time . But the fat soluble vitamins like vitamin d are not excreted this way. In fact it is a GOOD thing that you store vitamin d because this was how humans were designed!
Sometimes doctors will give extremely large-sounding dosages, up to as much as 600,000 IUs all at once, and some forums out there are saying, Oh no, thats bad because you store the Vitamin D, there is just simply no worry about this. To store vitamin d when its in excess is what our bodies do. While certainly too high of dosages for too long can lead to Vitamin D Toxicity, that is NOT the same thing as storing vitamin d. Too much is TOXIC, but storing vitamin d is a natural healthy body process that no one should Worry about.
Kerri Knox, RN
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How Does Your Body Absorb Vitamin D
The way you absorb vitamin D depends on whether you’re getting it from food or sunlight:
- Food/supplements: After you eat food or take supplements with vitamin D, your body stores it in fat cells until it is needed. At that point, the liver and kidneys transform the stored vitamin D into the active form the body needs known as calcitriol via a process called hydroxylation.
- Sunlight: Your body’s process for making vitamin D works similarly after sun exposure. The main difference is that the sun first triggers a type of cholesterol found in the body called 7-dehydrocholesterol. This starts the process of vitamin D production and transport where it moves to the liver and kidneys, much like after you eat foods with vitamin D.
However, not everyone can easily obtain or absorb vitamin D.
Renal Production Of 1252d
1,252D is the most potent metabolite of vitamin D, and mediates most of its hormonal actions. 1,252D is produced from 25OHD by the enzyme 25OHD-1 hydroxylase . The cloning of CYP27B1 by four independent groups ended a long effort to determine the structure of this critical enzyme in vitamin D metabolism. Mutations in this gene are responsible for the rare autosomal disease of pseudovitamin D deficiency rickets . An animal model in which the gene is knocked out by homologous recombination reproduces the clinical features of this disease including retarded growth, rickets, hypocalcemia, hyperparathyroidism, and undetectable 1,252D . Unlike Vdr null mice and VDR mutations in humans, alopecia is not part of this phenotype.
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How Quickly Will Vitamin D Levels Drop After The Summer
Often referred to as the Sunshine vitamin,vitamin D can be best utilized by your body when it is metabolized by direct exposure to sunlight. While the family of D vitamins ranges from D1 to D5, the most important for you metabolically are D2 and D3 .
Vitamin D is integral for many physiological functions, including calcium absorption and bone health. A deficiency in vitamin D can put you at risk for bone diseases, compromised heart and nerve functioning, mental confusion, and even kidney damage.
In light of these health concerns, many people wonder how long their vitamin D reserves will last into the winter. Will a summer of sunbathing sessions give you enough vitamin D to stay healthy until springtime? Understanding the factors that affect how vitamin D is stored in your system will answer this question.
Ways To Get Vitamin D
You can get vitamin D in three ways: by eating foods that contain it, by taking supplements or by spending time in the sun. Few foods contain vitamin D fatty fish such as salmon, liver, egg yolk and fortified foods such as milk and orange juice help you meet your daily needs. Unless you overdose on cod liver oil, eating foods containing vitamin D won’t raise your vitamin D levels too high. You also can’t get too much vitamin D by spending time in the sun, since other substances your body produces will prevent overproduction. If you take high supplemental doses of vitamin D over time you can overdose, since vitamin D builds up in your body.
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Is It Best To Get Your Vitamin D From The Sun Definitely Not
David J. Leffell, MD, Yale Medicine dermatologist and chief of Dermatologic Surgery
One of the biggest challenges weve faced in dermatology and in the world of skin cancer prevention has been a lot of misinformation about vitamin D metabolism.
There are claims that one needs to get a certain amount of sun exposure every day in order to produce enough vitamin D to be healthy. Its just not true. The majority of people can get their vitamin D from nutritional supplements and from vitamin D-fortified foods.
There are some people who have advocated for tanning to get vitamin D. But we know that UVB light causes skin cancer and that protecting yourself against it makes sense. As a doctor who treats patients who have melanomas, I want the general public to be advised that under no circumstances can use of a tanning bed or tanning in general be justified on the basis of vitamin D. Take a supplement instead.
Storing Enough Vitamin D
Can you tell me if the vitamin D you get from sun exposure during the summer is stored in the body for use in winter months when sunlight is less available? Also, should African-Americans use sunscreen since it blocks the ultraviolet rays needed for the body to make vitamin D?
Andrew Weil, M.D. |July 28, 2016
Most adults are not getting enough vitamin D, which we need for bone health and, more and more research suggests, for protection against a number of diseases including many types of cancer. We get vitamin D from fortified milk and cereals as well as from eggs, salmon, tuna, mackerel and sardines, and our bodies make it with exposure to sunlight. Unfortunately, many people dont get optimal sun exposure, particularly in northern latitudes during the gray winter months. In addition, sunscreen blocks vitamin D synthesis in the skin, and dermatologists have made us so fearful about UV damage to skin that many people dont get enough direct exposure to sunlight regardless of where they live.
Because so many people dont get sufficient vitamin D from sun exposure or their diets, I recommend a daily supplement of 2,000 IU. Use the D3 form and take it with a fat-containing meal to ensure absorption. There are no concerns about toxicity with this dose of supplemental vitamin D .
Andrew Weil, M.D.
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How Your Body Makes Vitamin D
You can get more than 80 percent of the vitamin D you need from the sun. The ultraviolet B radiations of the sun convert 7-dehydrocholesterol — a compound found in your skin’s epidermis — to previtamin D-3. The body then converts previtamin D-3 to vitamin D-3 in a process that consumes heat. Your body’s production of previtamin D-3 depends on factors like your skin pigment, seasons, time of the day, sunscreen use and clothing.
What Happens If You Take Too Much
It is a myth that it is easy to overdose on vitamin D.
Vitamin D toxicity is very rare and only happens if you take very high doses for extended periods .
The main symptoms of toxicity include confusion, lack of concentration, drowsiness, depression, vomiting, abdominal pain, constipation, and high blood pressure .
SUMMARY
Vitamin D toxicity is very rare. The symptoms include confusion, drowsiness, depression, constipation, and high blood pressure.
Vitamin D is a fat-soluble vitamin important for bone health.
For those low in this nutrient, increasing intake may also reduce depression and improve strength.
Your skin produces vitamin D when exposed to sunlight. Foods like fatty fish, fish oil, and liver also contain vitamin D as well as certain fortified foods and supplements.
Deficiency is fairly common due to limited sunlight exposure and a small selection of rich dietary sources.
If you dont spend much time in the sun and rarely eat fatty fish, consider supplementing.
Getting enough vitamin D can go a long way to boosting your health.
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Regulation Of Active Vitamin D Synthesis In Extra
Numerous studies have shown active vitamin D synthesis by 1-alpha hydroxylase enzyme is not only a renal feature . The gene encoding the 1-alpha hydroxylase enzyme and the vitamin D receptor gene can be expressed in many cells or tissues such as skin, placenta, prostate, parathyroid, bone tissue, colon, lung, breast tissue, monocytes and macrophages, as well as renal cells. It has been reported that active vitamin D synthesized in the aforementioned tissues functions mostly as an intracrine or paracrine factor in the tissues where they are located, and does not contribute to the active vitamin D levels in the circulation, except for some special cases . Since PTH and FGF-23 receptors are not found in these tissues, they are not directly involved in controlling active vitamin D synthesis. However, it is propable that PTH increases the effect of vitamin D through posttranscriptional modification . Unlike in other tissues, in activated macrophages, there is also no negative feedback of active vitamin D on 1-alpha hydroxylase enzyme . Moreover, although the 24-hydroxylase enzyme is expressed in these cells, its function is not fully understood. Cytokines such as IL-1, TNF-, IFN- induce the synthesis of active vitamin D in keratinocytes. Unlike macrophages, keratinocytes have a fully functional 24-hydroxylase enzyme activity and is induced by active vitamin D. In this way, active vitamin D limits its own synthesis in the epidermis through alternative catabolism .
Can I Get Too Much Vitamin D
Here is where things get interesting. If you are taking vitamin D supplements, you should not exceed more than 600 IU per day if you are an adult. The reason for this is that toxicities can occur from high doses of vitamin D supplements.
If, however, you get your vitamin D from the sun or from the foods that you eat, there is no risk of overdose. When you get your vitamin D naturally, the body does not react negatively to it, no matter how much you get.
You could literally spend 5 hours a day unprotected in the sun every day and never overdose on vitamin D. You might develop skin cancer and your skin may look like garbage, but the vitamin D absorbed through the skin will simply store away until you need it. Once your body cannot store anymore, the body stops absorbing it.
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How Long Will Vitamin D Last In Your Body
Because the previously listed factors affect vitamin D metabolization and any excess amounts are stored in fatty tissue, it’s difficult to make broad statements about how long a seasonal dose will last in the body.
Generally speaking, healthy people store roughly a three-month supply of vitamin D within their bodies during the summer months.
To determine how long a compound stays within your body, doctors look at its half-life, or the length of time it takes for half of it to be removed from the body. The half-life of calcidiol, a compound connected to vitamin D, is 15 days, though this doesn’t take into account the percent of vitamin D stored in body tissue.
A more precise picture comes from studying the effects on calcidiol levels of a single dose of oral vitamin D over time. A study published in the American Journal of Clinical Nutrition determined that patients given a dose of 100,000 IU of vitamin D maintained elevated levels in their blood for longer than 84 days. However, this research doesn’t consider the impact of vitamin D metabolized from sunlight.
Storage rates of vitamin D can also vary depending on many factors, including weight levels. For instance, some research indicates that obese subjects worked through their vitamin D stores more quickly than those of standard weights. Likewise, vitamin D that was stored in their tissues was rarely released when needed.
