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Vitamin D

Posted: Feb 12, 2007 8:15 pm
by Nutrients
Vitamin D

Vitamin D is a fat soluble vitamin that is found in food and can also be made in your body after exposure to ultraviolet (UV) rays from the sun. Sunshine is a significant source of vitamin D because UV rays from sunlight trigger vitamin D synthesis in the skin.
The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. By promoting calcium absorption, vitamin D helps to form and maintain strong bones. Vitamin D also works in concert with a number of other vitamins, minerals, and hormones to promote bone mineralization. Without vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults, two forms of skeletal diseases that weaken bones.

Research also suggests that vitamin D may help maintain a healthy immune system and help regulate cell growth and differentiation, the process that determines what a cell is to become.

Where do I find Vitamin D?
Vitamin D is produced in skin exposed to sunlight, specifically ultraviolet B radiation. Very few foods are naturally rich in vitamin D, and most vitamin D intake is in the form of fortified products including milk, soy milk and cereal grains.

What are the health risks of too much vitamin D?

Vitamin D toxicity can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss .It can also raise blood levels of calcium causing mental status changes such as confusion. High blood levels of calcium also can cause heart rhythm abnormalities. Calcinosis, the deposition of calcium and phosphate in the body's soft tissues such as the kidney, can also be caused by vitamin D toxicity.

Vitamin D malnutrition.

Vitamin D malnutrition may also be linked to an increased susceptibility to several chronic diseases such as high blood pressure, tuberculosis, cancer, multiple sclerosis, chronic pain, depression, schizophrenia, seasonal affective disorder and several autoimmune diseases.

How much vitamin D do we need? UPDATED: 01 2019

Code: Select all

Ages      International Units         mcg/d
0–12 months*   400 IU                    10
1-69           600 IU                    15
70 +           800 IU                    20

When can vitamin D deficiency occur?

A deficiency of vitamin D can occur when dietary intake of vitamin D is inadequate, when there is limited exposure to sunlight, when the kidney cannot convert vitamin D to its active form, or when someone cannot adequately absorb vitamin D from the gastrointestinal tract.

Vitamin D on NIH
Vitamin D on Wikipedia

Posted: Mar 4, 2007 12:49 pm
by Backwood
Vitamin D deficiency may be linked to cancer and at the same time over exposer to sunlight is also linked to cancer.

Does a solarium session help generate vitamin D in the body?

Re: Vitamin D

Posted: Jan 14, 2010 11:49 am
by AndyBa
Vitamin D is usually not found in vegan products unless they are fortified but here are those few that have some vitamin D :
Vegan Products Rich in Vitamin D

Vitamin D can also be found in UV exposed mushrooms: ... minD-desc/

Re: Vitamin D

Posted: Oct 1, 2010 10:27 am
by markwilson419
Nice post!
Vitamin D is necessary for the health we can also get vitamin D from the Sunlight.

Re: Vitamin D

Posted: Oct 4, 2010 4:13 am
by meign
Thank you so much for this posts... all the while I thought Vitamin D is only sunshine vitamin.

Re: Vitamin D

Posted: Dec 11, 2010 8:52 pm
by AndyBa
actually vitamin D is in deed mostly a sun vitamin.
the food sources are neglectable in comparison to the amount synthesized through sun exposure.

Re: Vitamin D

Posted: Jan 26, 2011 12:19 pm
by Berlingo
Most yogurt has some Vit. D, approx. 10%. The info given about Calcium blocking Vit. D absorption is incorrect

Re: Vitamin D

Posted: Jan 27, 2011 9:11 pm
by EnergieFitness1
A few things...

First, the RDA of vitamin D is very low. Therapeutic levels of vitamin d3 don't start until at least 2,000 iu (50 mg).

Consider this, if you lay out in the summer wearing a bathing suit, your body produces about 1,000 iu every 5 to 7 minutes.

Here in Seattle, where the sun hides behind the clouds 6 months out of the year (and for people who don't get outside), I recommend my clients supplement 5,000 iu per day. This should be your daily goal for d3 combining sun exposure and supplementation.

Re: Vitamin D

Posted: Apr 22, 2011 7:41 pm
by Dacite
Good vitamin D also can be found in flax seeds.

Re: Vitamin D

Posted: Jul 6, 2011 2:45 pm
by pauline2009
I noticed nobody mentioned about Vitamin D promoting calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent hypocalcemic tetany. It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts . Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps protect older adults from osteoporosis.

Re: Vitamin D

Posted: Jul 5, 2012 3:30 am
by xplr60
Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol .


Re: Vitamin D

Posted: May 8, 2015 7:50 am
by Stelawn
Try to wake up early in the morning and go for a 20 min walk. The sun rays are the natural source of vitamin D and nothing can beat it.

Re: Vitamin D

Posted: Mar 10, 2018 4:52 pm
by expialidocious
I was wondering about an upper limit for supplementation. There are some clues in the medical literature for an educated guess. Vitamin D intoxication: case report, etc.

This report describes a patient who presented worsening of renal function and hypercalcemia. After investigation, vitamin D intoxication was confirmed and it was due to an error in compounding (he was taking approximately 50,400IU per day).

The cases of hypervitaminosis D usually occur in excessive supplementation. The upper limit of daily vitamin D intake needed to cause toxicity is unknown; however, up to 10,000IU per day was considered safe in a healthy population.

Another paper says that proposed doses of around 10,000IU per day for healthy adults would probably suffice to maintain vitamin D levels, with practically zero risk of toxicity. The Big Vitamin D Mistake: Undeniably, further studies are needed to clarify the optimal supplementation of vitamin D, although it is uncertain whether a universal recommended dietary allowance is feasible.

Evaluation of vitamin D3 intakes up to 15,000 international units/day: None of the participants developed any biochemical evidence for vitamin D toxicity.

Vitamin D: Deficiency, Sufficiency and Toxicity: Vitamin D hypersensitivity syndromes are often mistaken for vitamin D toxicity.

Dietary Reference Intakes for Calcium and Vitamin D: In the United States, vitamin D can now be found in multi-vitamin/multi-mineral formulations as well as a single supplement in a range of dosage levels, including 1,000 to 5,000 IU of vitamin D3 per dose and even up to 50,000 IU of vitamin D2 per dose. In Canada, dosage levels of vitamin D above 1,000 IU are obtainable only with a prescription.

Correcting vitamin D deficiency using over-the-counter supplements: A patient was taking over-the-counter vitamin D3 for the treatment of deficiency. Her therapy had increased her vitamin D serum levels, but not sufficiently. She therefore needed an increase to 2,000 IU daily to further raise her levels and put her within her target goal.

Should I prescribe sunlight instead of vitamin D? According to the American Academy of Dermatology and the Canadian Dermatology Association position statements on vitamin D, there is no scientifically validated, safe threshold level for ultraviolet exposure from the sun (or indoor tanning devices) that allows for appropriate vitamin D synthesis without increasing the risk of skin cancer.

Sounds like toxicity (as it were) is more likely from the sun, but if you can't avoid that, then supplements could compound it, and this is probably why setting a universal dietary allowance for vitamin D is tricky. It depends on where you live, what season it is, or how often you're outside.

Re: Vitamin D

Posted: Jan 3, 2019 10:51 am
by AndyBa
Dacite wrote:Good vitamin D also can be found in flax seeds.

Flax seeds don't have any vitamin D, unless they are fortified.