What does Vitamin D do for the body

This article is about what does Vitamin D do for the body, but before we get in to that, let me explain a little bit about Vitamin D:

Vitamin D is the sunshine vitamin, it is something we get through sunlight rather than from food. Actually, some foods do contain Vitamin D but it is nowhere near enough to replace what we get from the sun. The recommended daily allowance is about 600 IU, whereas we can produce more than 10.000IU in about 30 minutes of full sun exposure, which is over 15 times more than the government recommends for us to take.

Scientists have started to realize this, and have recently recognized that the benefits of Vitamin D are not just implicated in bone diseases like rickets, but in a host of other serious disorders and illnesses.
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What does Vitamin D do for the body?

Vitamin D is a fat soluble vitamin, and functions as a steroid hormone. What steroid hormones do is go in to the nucleus of cells, and alter gene expression, that is turning genes on or off, or simply giving them a nudge in either direction (more info on Vitamin D Function here). Other steroid hormones include testosterone, aldosterone and many more. Being deficient in a hormone is pretty serious, and Vitamin D is no exception.

What this implies, is that people who don’t get enough sun year round are probably deficient in a major hormone in their bodies. A hormone, whose lack of has been implicated in some serious illnesses.

What does Vitamin D do for diseases?

  • Reduce chances of heart disease
  • Dramatically reduce chances of cancer
  • Extremely helpful against osteoporosis
  • Very good for the immune system
  • Helps fight depression
  • Reduces acne
  • Helps reduce chances of getting Alzheimers
  • May also help with weight loss
  • Help prevent pathological muscle weakness
  • Combat type II diabetes and the metabolic syndrome

The list goes on and on and on… I’m not gonna go dig up all the promising studies on Vitamin D since that would take many days, but if you need proof then take a look at the Vitamin D Council Research section.

I recommend that anyone who lives in the northern atmosphere, or doesn’t get a lot of sun throughout the year, get tested by a doctor as soon as possible. The symptoms deficiency can be very subtle, and you may not ever realize you had a Vitamin D deficiency until it is too late.

Out of the causes of deficiency, lack of sunlight is the biggest factor, but other things such as eating a low-fat diet or making poor use of the little Vitamin D that the body has can matter as well. Getting enough Magnesium and minimizing gluten grains will help with Vitamin D absorption. However, for a lot of people, it may be necessary to take a supplement in order to properly correct a deficiency.

It should be aimed to have a blood level of about 50-80 ng/ml, and someone who has less than 30 ng/ml is most surely deficient and should take action as soon as possible. I recommend taking Vitamin D3 (cholecalciferol), oil filled gel caps, up to 5000 IU every day and possibly even higher, but it would be necessary to have a blood test done regularly in order to adjust the dosage properly.

There really is no need to worry about Vitamin D Toxicity unless you take insane amounts, but a Vitamin D overdose has been reported after several months of taking 50.000IU per day.


  1. What are the names of drugs that someone can take during painful menstruation?

    • Take Aleve. It is a lower dosage of Anaprox (which is given to relieve arthritis symptoms. It was discovered that women who took Anaprox didn’t have cramps–and so, Aleve was born). I took it for almost twenty years and I was free of pain!!!!! If it is really painful and Aleve doesn’t work, ask your doctor for Anaprox….

      Take care…..DebraV

  2. I have no idea, sorry.

    I’m sure your doctor has the answer, though.

  3. susan gardner says:

    I just found out I have low vitamin d and I have no clue what it is.

    • Susan Benson says:

      In addition to what Kris has said… Trying to get Vitamin D from the sunshine is highly unlikely, especially if you are already deficient. If you are dark skinned it will take you up to three times as long to get only half of what it would a fair skinned person. Also, if you live in certain areas it would also be difficult, such as Seattle…
      The doctor, or whoever told you that you are deficient – hopefully you know this from a blood test, would be the best bet to let you know what types of medication (usually high dose Vitamin D – a once a week pill that will contain around 20,000 IU of vitamin D). Also, fish is a great source. They have cans of salmon at the grocery store that contain the fish bones in it, this is high in vitamin D and calcium and the fish oil is a bonus!!! I know it sounds a bit gross, but you can make salmon cakes that are wonderful tasting out of it and the bones are very soft and just mix in! Hope it helps!!!

  4. Susan: If you have low Vitamin D, then you either need to get more sun or start supplementing with Vitamin D3, in oil-filled caps.

    A good starting point would be 4000IU in a day, but then you need to have a blood test done in a few months time to measure 25(OH)D and adjust your dosage accordingly.

    It should be in the 30-80ng/ml range.

    It would be best if you would speak to your doctor about this and have him decide the dosage for you.

    • Mary Merrall says:

      Question – When I take the 50000 IU once a week that my doctor prescribed it makes me feel completely drained/tired, nauseated and sick. My dr. said that is not the cause. This only happens the day I take this large dosage. It is a gel cap so I can’t cut it in half.
      I only feel sick the day I take it….any suggestions?

      • You could try a different brand.

        You could also try a smaller dosage, spread throughout the week, such as 7.000IU per day (7 days x 7.000IU = 49.000IU).

      • Mr.Knowitall says:

        That’s retarded. Go see a different doctor. I can’t think of any situation where some one should take that much vitamin D in one go. Take less or at least spread out the dose to less IU once a day, as opposed to taking a ridiculous amount in one go for the whole week.
        Taking too much of anything will make you feel sick.

  5. I have no energy sometimes and someone reccomened Vitiman D to me, would this help ?

    • Susan Benson says:

      Try fish oil and be sure that you are drinking plenty of water. The vitamin helps your hormones work better (in lamest terms!). Also, if you are overweight the fat in your body will “sequester” the vitamin D you are consuming and make it unavailable for your body to use. This is because it is a fat suluble vitamin.

    • Vitamin B12 is the vitamin you should be taking, It increases your engery levels. and has many other benifits. but, vitamin D would help too, just B12 is the energy vitamin.

      • I don’t think B12 is going to do much unless you are deficient in it, that being said a deficiency is definitely a possibility, especially for those who eschew animal products (vegans).

  6. Brynn,
    it is definitely possible, although tiredness can be caused by many different things. There’s no harm in going to the doctor to check if you are Vitamin D deficient or not, and to discuss the lack of energy.

  7. Susan Benson says:

    What about all of the effects of Vitamin D with Calcium? I think you missed a huge one there!

  8. Well, Vitamin D enhances absorption of Calcium from the digestive tract, but I don’t believe there is a big risk of Calcium deficiency so I don’t really see that it matters much.

  9. Does having a vitamin d deficiency cause you to be extremely tired all the time?

  10. samantha garrison says:

    Awesome! All this information has really helped me. My doctor said that I have low vitamin D and before reading this I had no idea what she was talking about. Does low Vitamin D feel like you’re completely drained without feeling tired?

  11. In researching MS vitamin D3 is mentioned. What would this vitamin do for MS in an 11 year old cjild?

  12. Vitamin d deficiency can make you glucose intolerant too and if you’re severely malnourished for the fat soluble vitamin and eating low saturated fats diets it can make you very fat too. after all fat is where these nutrients are stored. if you tend to run low due to dietary deficiencies then you body wants to hoard them and you need more fat cells for that and the more you need to hoard the fatter you become. If you need to produce the fats you need too due to low fat eating which translates into high carb diets they convert glucose to fat that you need.

    The less glucose you can utilize due to resistance the more fat cells you need to convert to fat you can still use fat even when insulin levels are high. Thus the more nutrient deficient you are and insulin resistant you are the fatter you are. that is why low calorie diets seldom work as you just make the malnourishment worse.

  13. My doctor has just put me on an 8 week treatment for Vit D deficiency with a prescription. I am still confused about what it all means. I am doing research as to what it is, the symptoms but it is all overwhelming. Anyone has any advice?

  14. Kananan says:

    I have vit D level 31.02nmol/L is it for men or but i feel weakness and pain in bone aslo but i checed other test calcium in 8.2 so any health problem how i improve both ca and vit d level so kindly advice.

    • Kristjan says:

      You should talk to your doctor and consider supplementation, or increasing your sun exposure and dairy intake.

  15. Bruce Norton says:

    Interesting information, I am in the process of doing a 4 year study on the value of vitamen D for the University “VIDA Study”, I am trying to find out as much information about vitamin D as I can. It will help me understand the value of the program I am undertaking !

  16. I had a. Blood test to check this the doc said it is dangerlish low what could this effect

  17. My Doc put me on 50.000 iu a week for 8 weeks then 400 iu 2 a day know has me back on 50.000 iu a week for the next 9 weeks I am over weight and don’t sleep very well I no that 50.000 iu is vitamin d2 not d3 . can vitamin D3 help with my weight and sleep problem ?

  18. Moon Child says:

    Hi, I have read the comments on this article and am blown away at the information. I have a couple of other questions where I need some clarification. A few years ago I found out that some of my digestive issues were due to a severe gluten intolerance. 4 years later I have found myself eating whole foods with no gluten. However, I am also lactose intolerant. So, no dairy. Last year I started a weight loss personal program. Basically this is eating proper portions, whole foods, not frying foods, drinking plenty of water (still working on that one) and exercise. Doing tons of research I decided to ask my Doctor during my yearly blood work to look into V. D and wouldn’t ya know I am deficient in it (severely). I have been given a 2 week prescription. I am African American and in the Northern Hemp. We don’t have a lot of sunshine year round here. I read the list of diseases and dis-eases that V. D can assist in helping you to avoid. 1. Digestion, heart disease etc. which I think are amazing. However, my next issue is how exactly does V. D add in being over weight, gluten etc.??? Is there any where else I can find more info on this? My health is very good and I want to KEEP IT THAT WAY. I plan on going back to my primary care physician and having a long talk. WHY DOESN’T THE MEDICAL COMMUNITY SHARE THIS INFORMATION WITH PATIENTS??!!

    Thanks for your Time.

    • Vitamin D deficiency can cause a lot of things and gluten intolerance can exacerbate vitamin d deficiency.

      Also, if you have dark skin then you will produce very little Vitamin D in the little sun that you get there in the North.

      Good chances are you will need to keep supplementing. Make sure to take D3 (not D2) and take a large enough dose. Probably best to get your test repeated in a few months.

      You should definitely discuss all this with your doctor.

  19. I am a sixteen year old girl, I get plenty of sunlight (if anything, more than I should) but I was just recently diagnosed with depression and I have a history of quite a bit of anxiety. We did a blood test to check my hormones and such for my depression and we found that my vitamin d is low, at about a 22. I eat quite healthily and am a fairly well balanced person. What could this mean? Could this be a factor in my depression at all? All comments would be tremendously helpful! Thank you

    • I believe Vitamin D levels can affect depression, but considering that you aren’t severely deficient then I personally doubt that it is a major contributing factor.

      You should seek professional help. Depression and anxiety are treatable.

  20. Yep! I am on some medication. Thank you for your help!

  21. Jeanette Mofokeng says:

    I have been told that i suffer from the lack of vitamin D becouse i often get thirsty, severe headaches and constipated. If it is true that i lack vitamin D in my body what name are the pills with vitamin D?

  22. I just found out today I have low vitamin D my doctor said it was at 8. I asked if this was bad and he said it could be but did not go into detail instead said he was sending me to a hematologist and I could ask them all the questions. I’m worried as I do not know if this is bad. I know I will be getting another doctor but if you could help me understand this better I would really be greatful. Thank you.

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