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How many people know about vitamin D?

Posted on: July 7, 2012   by  Brant Cebulla


Ever wonder how many people know as much about vitamin D as you? Last summer, Professor Sandra Clips and colleagues from John Hopkins University wanted to know this, too, and published some interesting results.

Clipp, SL et al. Sun-seeking behavior to increase cutaneous vitamin D synthesis: When prevention messages conflict. Public Health Reports, 2011.

In 2007, they sent out a questionnaire to a group of people who lived in Washington County, Maryland (a semi-rural county) in 1989 and have been followed ever since. From this questionnaire the researchers sent out, they got a total of 8,027 valid responses.

Here is what they found:

  • 30% were aware that unprotected sun exposure increased vitamin D levels.
  • Women were a little more aware of this interaction than men (32% vs. 28%).
  • Education was a significant factor. Awareness increased from 23% to 25% to 38% among those who had <12, 12 and >12 years of education, respectively.
  • 42% of people who took vitamin D supplements were aware of the vitamin D-sun exposure interaction compared to just 25% of non-supplement users.

Did people who were aware that sun exposure increased vitamin D levels actually seek sun exposure?

  • 42% who were aware of the interaction sought sun exposure for vitamin D.
  • Women were more likely than men to seek the sun for vitamin D (45% vs. 35%).
  • Vitamin D supplement users were much more likely to seek the sun for vitamin D than non-supplement users (49% vs. 35%).

Although not surprising, the most attention-grabbing finding here is that vitamin D supplement users are more likely to be aware that sun exposure increases vitamin D levels and that they are more likely to seek sun exposure for this reason.

People ask, “If I live in a sunny climate, why do I care about vitamin D supplements?” This study, from a public health perspective, is a good illustration of why sun exposure and supplements go hand in hand. If you take a vitamin D supplement, you are more aware of the issue, more aware that you need vitamin D from either the sun or a supplement substitute.

If you don’t take a supplement, you are more likely to be blind to the whole issue. My guess is that even if you are aware that the sun increases vitamin D production but do not take a supplement, you are probably less likely to be interested in the nuances of getting the right amount of vitamin D. In the 21st century, the public needs to be aware that both sun exposure and supplements can be part of getting the right amount of vitamin D.

6 Responses to How many people know about vitamin D?

  1. [email protected]

    Right! Good!

    So how do we inform people? people who, in many ways do not want to change something in their lifestyle … there is much to say when it comes to understanding and doing. Think about those with severe allegies, they do not go out at all in spring-summer, if they can avoid it, – what D3-levels do they have? Have you seen all 1-2 year olds, with legs looking like wheels! Just saw some pictures of the son of a famous stylist, Rachel Zoe … poor kid, legs like wheels, too much SPF?

    As I said before, I do not get burned, even if I did not burn easy before either. I take my 50 000 IU per weak the year around, we have so bad summers in Sweden, and I live in the south! I just checked my D3-level and it is just as I want it, 197 nmol/L, that would be lika 80 ng/mL.

  2. [email protected]

    Here are the results of many other surveys, from doctors, mid-wives, lifeguards, those with dark skins, etc. http://www.vitamindwiki.com/tiki-index.php?page_id=2986
    A LOT of education is needed about sunlight and vitamin D.

  3. Jeffrey J

    I was wondering if you have seen this recent study?
    Too Much Vitamin D Can Be as Unhealthy as Too Little, Study Suggests:

    From the story:

    “If the blood contains less than 10 nanomol (nmol) of vitamin per liter of serum, mortality is 2.31 times higher. However, if the blood contains more than 140 nmol of vitamin per liter of serum, mortality is higher by a factor of 1.42. Both values are compared to 50 nmol of vitamin per liter of serum, where the scientists see the lowest mortality rate.”

    My comments:

    In other words, the study showed a significantly higher total mortality risk for low levels of Vitamin D, versus higher levels, but I have a couple of questions. Were they testing for 25(OH)D levels, and how many people were in the high vitamin D level group, out of the quarter million samples that they tested?

    In any case, the following chart shows disease prevention by Serum 25(OH)D level. Curiously enough, there are no data on the chart showing any beneficial effects from blood levels above 55 ng/ml (about 135-140 nmol/L), either because there is no evidence of beneficial effects, or perhaps because there are so few people with higher blood levels, but in any case, it’s a null data set.

    It seems to me that the linked study would basically seem to confirm existing research, in the sense that there does not seem to be any evidence of beneficial effects of Vitamin D in excess of about 140 nmol/L, but there is a dramatically increased higher mortality risk associated with low levels of Vitamin D.

    Disease Prevention by Serum 25(OH) D Level:


    In any case, any comments?

  4. Kcal

    It would help, I believe, if vitamin D was not called a “vitamin.” When I mention it to people their reaction is often, “Oh, another vitamin.” And it’s true that many, if not all, vitamin supplement advantages have been debunked, or can even be harmful. Perhaps a more appropriate name could get more (deserved) attention.

  5. Brant Cebulla

    Kcal, I do think people would take vitamin D nutrition a little more seriously if it was considered a hormone. However, if it had been classified as a hormone the day it was discovered, would we readily be able to purchase vitamin D supplements today?

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