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Importance of Getting Adequate Vitamin D

Updated on January 31, 2014

Vitamin D is loosely known as the sunlight vitamin. Your body makes vitamin D when skin is exposed to sunlight. However, many people in certain parts of the world that is far from the equator do not get enough sunlight (especially in the winter) for optimum vitamin D production.

Also the ultraviolet B radiation of sunlight that is needed for this production is blocked by glass and by sunscreens (as in sunscreen lotions). So your skin can not generate vitamin D if you are sitting inside a car or an office even with sunlight streaming though the closed window.

In an episode of the radio program The Sound of Ideas, two of the guests, Joe Graedon and Dr. Susan Joy, both agrees that the body cannot generate vitamin D when sunlight is going through a window.

People with darker skins will need greater sun exposure. Same for people who are farther from the equator.

Generally speaking, people need about 15 minutes in the sun (as in a short walk) several times a weeks -- preferably with good skin exposure and between 11am and 1pm in order to get the UVB rays.[6][8]

From an evolution perspective, out bodies is used to the sunlight when in prehistoric times it was running around hunting and gathering in the sun. Our modern indoor society have lead to roughly 40 to 50% of Americans deficient in vitamin D.[1][8]

Dr. Cannell Founder of Vitamin D Council

Below is a very informative video about vitamin D with discussion between Dr. Mercola and Dr. Cannell. Dr. Cannell is the founder of Some key take-away points are ...

  • The test to determine this is 25-hydroxyvitamin D, or 25(OH)D, test. Not the 1,25-dihydroxyvitamin D test
  • Anyone with an autoimmune condition should have their vitamin D levels tested.
  • It is important to get enough vitamin D during pregnancy.
  • Vitamin D produced by the UVB rays hitting the skin is superior to supplements. But supplements are still necessary since many people in higher latitudes do not get the right sun angle many times of the year. And when the sun is out during the summer, they are indoors working. The sun angle needs to be 50 degrees or more in order for UVB rays to penetrate the atmosphere.
  • It is possible to get a tan from the UVA rays and still not be getting any vitamin D due to the lack of UVB rays.
  • As one becomes adequate in vitamin D, the skin becomes less sun-sensitivite. So sunburning easily is a sign of vitamin D deficiency.
  • Make sure you take vitamin D3 and not vitamin D2. Vitamin D2 is not found in the body and is not produced naturally. Vitamin D3 is.

Vitamin D for Bone Health

One of the main importance of vitamin D is bone health. Without vitamin D, your body can not absorb calcium. That is why you many manufacturers put vitamin D in with calcium supplements. And that is why vitamin D along with calcium helps prevent osteoporosis.

Reader's Digest Your Health, What Works, What Doesn't says ...

"No matter what form of calcium pill you take, it won't do much good if you're low on vitamin D, which stimulates the intestines to absorb calcium. It has become increasingly evident that adequate vitamin D is essential of preventing osteoporosis -- not to mention various cancers." [page 189]

Vitamin D serves to modulate of cell growth. That is why vitamin D is protective against cancer. It helps reduce the incidence of breast cancer and colon cancers. Vitamin D deficiency is a risk factor for prostate cancer. Dr. Cedric Garland of UCSD School of Medicine says "every cancer patient should be taking vitamin D"[8]. However, some experts says that the relationship between vitamin D and cancer is still early and inconclusive and inconsistent as of April 2011.[reference]

Vitamin D helps reduce incidences of rickets, Type 1 Diabetes and multiple sclerosis[8]

Vitamin D provides neuromuscular functions. So it reduce falls in elderly people. article says ...

"Chronic vitamin D deficiency is often misdiagnosed as fibromyalgia because its symptoms are so similar: muscle weakness, aches and pains."[1]

Vitamin D deficiency increases inflammation in the body and has a negative impact on cardiovasular health.[9] A Harvard Medical School study showed that older people who have vitamin D3 deficiency had twice the risk of a heart attack.[6]

Vitamin D boosts immunity

Researchers are seeing an link between vitamin D and the immune system. Vitamin D is an immune modulator. Vitamin D deficiency may be a contributing factor to some autoimmune diseases.

The Milwaukee Wisconsin Journal Sentinel reports of a study of 19,000 people where it was found that those deficient in vitamin D (less than 10 nanograms per milliliter) were 55% more likely to have had a cold or upper respiratory infection. Whereas those with adequate levels of vitamin D, had 30 nanograms per milliliter of vitamin D.

The Journal also reports that flu outbreaks have mostly occur when solar radiation is at its lowest. We primarily get vitamin D from the sun rather than the limited quantities from our food. Because vitamin D is generated when sunlight hits our skin, we experienced more colds and flu during the winter due to decrease sun exposure.

So it is probably even more important to take your vitamin D during the wintertime.

The book Why Do I Still Have Thyroid Symptoms? When My Lab Tests are Normal writes ...

"Vitamin D appears to help again autoimmune-mediated thyroid dysfunction. Vitamin D appears to be helpful for autoimmune-induced diabetes. Numerous papers have been published linking autoimmune disease to vitamin D deficiency." [page 205]

Vitamin D reduce risk against autoimmune diseases

Vitamin D is an immune modulator and help protects against autoimmune diseases (like Type 1 diabetes, celiac disease, rheumatoid arthritis autoimmune thyroid, lupus, multiple sclerosis, etc) by maintaining the intestinal mucosal barrier and preventing leaky gut syndrome which is one of the first steps to developing autoimmune disease. It is believed that vitamin D keeps cells tight and close together and functioning better.

Frank Garland PhD provides lots of convincing studies that suggest that low levels of vitamin D is associated with increased risk of Type 1 diabetes which is an autoimmune disease. See video on right.

Dr. Hedberg also mentions the importance of vitamin D in reducing the risk of autoimmunity in a Hawthorn University webinar.

Vitamin D is one of the factors that can help heal a leaky gut as mentioned in the talk by Dr. Thomas O'Bryan.

My other article talks more about autoimmune diseases.

Dr. Patrick Krupka talks about MS, Vitamin D and Viruses ...

Vitamin D protective against Cancers

Liz Lipski talks about vitamin D reducing cancers. She likes to see 25(OH) at least 32.

How Much Vitamin D?

As you get older you need more vitamin D. How much vitamin D you need depends on many factors such as your individual makeup as to how efficiency you convert sunlight to vitamin D, where you live, and how much sun you get, and how dark your skin is.

The vitamin D dosage will depend on the individual. What you want to target is to get your serum 25-hydroxyvitamin D within the proper reference range. For some a small dose will give a large boost in serum levels. And for others, they need a large dose in order to get any rise in serum levels. This level has to be monitored with a blood test. Too much higher than the reference range can have potentially adverse effects.

What that serum vitamin D range is depends on who you ask. And when looking at the numbers, note the units that it is measured in. It can be measured in nmol/L or in ng/mL. Europe tend to favor the use of the former units of measurement; whereas, the United States tend to use ng/mL.

According to Office of Dietary Supplements at the National Institutes of Health, what is generally considered adequate for bone and overall health in healthy individuals are greater than 50 nmol/L or greater than 20 ng/mL.

Chris Kresser mentions that he recommends a moderate range of 35 to 55 ng/mL.[reference]

Video about vitamin D by UCTelevision says the reference range should be 40-60 ng/mL. That's nano-gram per milliliter. They also said that 2000 IU/day is safe and that there won't be any toxicity below 200 ng/ml.

The RDA (recommended dietary allowances) value for adults under age 50 is 200 IU. But for some that may be too low.

Dr. Mark Hyman's article in says that we may need up to 25 times what the government recommends in order to be optimally healthy. He writes ...

"Unless you're spending all your time at the beach, eating 30 ounces of wild salmon a day, or downing 10 tablespoons of cod liver oil a day, supplementing with vitamin D is essential."

Other values for amounts of vitamin D provided by the National Institute of Health[5] and Institute of Medicine[4], shows higher RDA value to be 600 IU for ages 1 to 70. And 800 IU if you are over 70.

These are really the minimum amounts that you need. Some recommend going to 1000 IU for optimal health. See video by GrassrootsHealth.

Dr. Shawn Talbott says in an interview in ...

"One good example is vitamin D - where we know that we absolutely cannot get an optimal amount (1,000-2,000IU/day) in our diets, nor can we produce enough in our skin during much of the year."[7]

And that is why he believes in the use of supplements. Epidemiologist Gary Schwartz says "If you're going to buy a supplement it's better to buy D3 than any other D supplement."[6] Vitamin D3 (also called cholecalciferol) is the biologically active form of vitamin D.

Dr. Datis Kharrazian says on episode 382 of the La Livin Low Carb Show that some people with autoimmune disease may need higher vitamin D levels.

One important point is that different people will require different doses. It depends on the genes and the amount of sun they are getting. The more important thing is the blood level of vitamin D. Get that measured and adjust the dose to get the blood level of vitamin D to its optimal level.

Dr. Mercola on Vitamin D

Upper Limit of Vitamin D

Vitamin D3 can be toxic when taken at 60 times the daily recommended allowance.[6] The Institute of Health and National Institute of Health both indicate the upper limit for vitamin D is 4000 IU if you are over 9 years old.[4] However, Reader's Digest Your Health: What Works, What Doesn't listed 2000 IU as the daily upper limit based on data from the US National Academy of Sciences.

WebMd says ...

"Vitamin D is LIKELY SAFE during pregnancy and breast-feeding when used in daily amounts below 4000 units. Do not use higher doses."

Other news reports says that long-term calcium and vitamin D supplements may be linked to higher risk of kidney stones.

Do not use tanning beds to get your vitamin D. Reader's Digest Your Health, What Works What Doesn't says so on page 377.

Some contra-indication of taking vitamin D is if you have granulomatous diseases, such as Crohn's, or TB, or sarcoldosis. You need to consult with your doctor in these cases.

The best and safest way to get vitamin D is by sun exposure, but not enough to burn.

Vitamin D balanced with Vitamin A

For every vitamin D receptor on our cell there are two vitamin A receptors. If you are deficient in vitamin A and take too much vitamin D, then vitamin D can become toxic at much lower doses than it would normally.

Vitamin A are in animal liver. Cod liver oil is a good source of vitamin A. And it also has some of vitamin D. However, since vitamin D is not stored in the liver, one can not rely solely on cod liver oil as a source of vitamin D. Some natural cod liver oil has only 20 IU of vitamin D. So one may want to supplement with vitamin D along with cod liver oil. Although some cod liver oil may have more due to artificially added vitamin D. So you need to check the vitamin D amount.

One may also considered taking the emulsified form of vitamin D. Book Primal Body, Primal Mind writes that ...

"Emulsified liquid forms of supplemental vitamin D may be a better choice for some people, as they are far better absorbed by most people and are much safer." [page 92]

Emulsification make it more water soluable so that body can more readily excrete the excess.

Although, the safest way to get vitamin D is from the sun (without sunscreen but not long enough to get burn). But depending on geography and climate, that may not always be possible.

Vitamin D Controversy

There are also some controversy over vitamin D such as mentioned on and Marshall Protocol Knowledge Base. The Marshall protocol is a protocol for treating autoimmune diseases that are caused by pathogen. It calls for the avoidance of vitamin D as referenced here.

Article on, writes ...

"Some researchers claim vitamin D is immunosuppressive; others argue it activates the immune system"

There is also the article ...

Waterhouse, J. C., Perez, T. H. and Albert, P. J. (2009), Reversing Bacteria-induced Vitamin D Receptor Dysfunction Is Key to Autoimmune Disease. Annals of the New York Academy of Sciences, 1173: 757–765. doi: 10.1111/j.1749-6632.2009.04637.x

which says that low levels of vitamin D may be due to ...

"chronic infection with intracellular bacteria that dysregulate vitamin D metabolism by causing vitamin D receptor (VDR) dysfunction within phagocytes. The VDR dysfunction causes a decline in innate immune function that causes susceptibility to additional infections that contribute to disease progression. Evidence has been accumulating that indicates that a number of autoimmune diseases can be reversed by gradually restoring VDR function with the VDR agonist olmesartan and subinhibitory dosages of certain bacteriostatic antibiotics. ... Disease reversal using this approach requires limitation of vitamin D in order to avoid contributing to dysfunction of nuclear receptors and subsequent negative consequences for immune and endocrine function." [from abstract]

What Doctor Chopra Says

Doctor Chopra himself takes 1000 IU of D3 and says it is the only vitamin he takes.[6]

In his book Doctor Chopra Says, he writes ...

"A deficiency of vitamin D3 has been shown to have a direct link to certain cancers and is also suspected of contributing to several other serious diseases."[6]

What Others Are Saying About Vitamin D

Many experts believe highly about vitamin D.

Dr. Jonny Bowden wrote article on vitamin D titled as "The Single Most Cost-Effective Medical Intervention" where within you will find a chart of optimal levels.

Dr. Mercola writes on his site ...

"when you consider the fact that you only have 30,000 genes in your body, and vitamin D has been shown to influence more than 2,000 of them, the bigger picture of its true impact on your health can be easily understood. It may, in fact, have literally thousands of health benefits!"[12]

Dr. Mark Hyman writes in The Blood Sugar Solution ...

"Your appetite control is impaired by low vitamin D levels."

Vitamin D may even help with seasonal allergies.[13]

Dr. Cannell studies vitamin D. And his theory is that vitamin D deficiency in the mother may be a contributing factor to autism in the child.[reference] There are some theory that sun exposure (which produces vitamin D) and sufficient vitamin D levels are protective of the brain.

Emulsified forms for vitamin D may have greater bioavailability.

Dr. Oz Recommends Vitamin D

In the video on the right, Dr. Oz says "Vitamin D to me is the most important vitamin." Note that here he says "vitamin" and not "supplement". Because later in the video he says the most important "supplement" is DHA Omega-3.

He himself takes a multivitamin, vitamin D, and Omega-3 every day. Yes you can combine a multivitamin that already contains vitamin D with another vitamin D pill, as long as the total of the two is around 1000 IU to 1200 IU. He feels that most multivitamin manufacturers do not put enough vitamin D in their multivitamins.

In a "Good Morning America" interview, Dr. Oz say that if there was one vitamin that he would push to everyone it would be vitamin D. And the best way to get vitamin D is through the sun.

Dr. Oz talks about vitamin on his show where he says that deficiency in vitamin D is implicated in more than 20 diseases. Guest on the show is Dr. Mark Hyman who says that vitamin D controls over 200 genes, some of which is involved with the important immune system that protects us.

Note that there is a difference between the vitamin D3 generate by the skin from sun exposure than from the vitamin D3 in supplement. The former is sulfated and the latter is not.

Stephanie Seneff writes that ...

"The skin also synthesizes vitamin D3 sulfate, upon exposure to sunlight. ... The body can't synthesize vitamin D3 sulfate from vitamin D3"

Vitamin D from Foods

It is true that fish, fortified milk, and eggs has some vitamin D. But the amounts are tiny and difficult to meet your needs from diet alone. Getting vitamin D from sunlight is more reliable.

For example, you would need 10 glasses of vitamin D fortified milk to get adequate amounts. One egg has only about 20 to 40 IU of vitamin D in the yolk. So you would need more than 2 dozen eggs per day.

It is more reliable vitamin D from sunlight.

Fish has higher levels of vitamin D. For example[5]...

1 tablespoon of cod liver oil: 1360 IU
3 ounces Sockey Salmon: 447 IU
3 ounces Mackerel: 338 IU
3 ounces Canned Tuna: 154 IU

Although, it looks like cod liver oil has a lot of vitamin D. But it turns out that cod liver oil also has high levels of vitamin A. Vitamin A and D compete for the same receptors in your body. So this decreases the effectiveness of vitamin D getting through when vitamin A is present.[8]

Also be careful of possible high mercury content in mackerel and tuna.


This HubPages article was updated March 2012 and is only opinion at the time of writing. This is not medical advice. Author is not a medical profession and may receive revenues from the links and display ads within content of article.

Consult with your doctor before taking supplements. Supplements can negatively impact prescription medicine and may not be suitable for certain individual cases or individual with certain conditions.


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