# Vitamin D: What is it good for? **URL:** \ **Category:** Factual Questions\ **Created:** [January 22, 2011, 3:10pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565 "2011-01-22T15:10:44Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [January 23, 2011, 3:54pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/21 "2011-01-23T15:54:33Z")
Here’s an overview of vitamin D and its implications in health and disease by Michael Holick, who is considered to be one of the world’s leading authorities on vitamin D: [http://www.ajcn.org/content/79/3/362.long](http://www.ajcn.org/content/79/3/362.long) > [@](#): > > Why should we care about vitamin D deficiency? \*\*It is insidious and has both short- and long-term consequences. Infants and young children who are vitamin D deficient may be imprinted for the rest of their lives with increased risks of type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and many common cancers (Figure 8). Adults are at increased risk of common cancers and cardiovascular disease. Recently, it has been reported that young adults with vitamin D deficiency were at greater risk of congestive heart failure than were their vitamin D-sufficient counterparts (73, 74). \*\* > > Therefore, to maximize health and reduce the risk of common diseases, it is reasonable to pay attention to the 25(OH)D concentration. Just as the blood concentration of cholesterol is often measured on an annual basis, so too should the blood concentration of 25(OH)D be measured. Indeed, vigilance in maintaining a healthy 25(OH)D concentration may have more important health ramifications than a simple lowering of a blood cholesterol concentration to prevent coronary artery disease. \*\*A minimum concentration of 25(OH)D should be 50 nmol/L, and, for maximum bone health and prevention of many chronic diseases, the 25(OH)D concentration should be 78-100 nmol/L. \*\* > > The simplest way to obtain vitamin D is from moderate exposure to sunlight. I recommend that exposure of hands, face and arms, or arms and legs to sunlight for a period equal to 25% of the time that it would take to cause a light pinkness to the skin (1 minimum erythemal dose) is sufficient not only to satisfy the body’s requirement, but also to make sufficient amounts of vitamin D to store in the body for use on rainy days and during times when sun exposure is inadequate to produce enough vitamin D in the skin. I have provided guidelines for the amount of sun exposure needed by people of all skin types to achieve their vitamin D requirement without significantly increasing the risk of skin damage and skin cancer (9, 39). Increasing the intakes of foods fortified with vitamin D, including milk, orange juice, cereals, and oily fish, is a reasonable approach to satisfying the body’s requirement. Taking \> 1 multivitamin is counterproductive, because too much vitamin A would be ingested, and that increases the risk of birth defects and osteoporosis. Alternatively, one multivitamin containing 400 IU vitamin D and a vitamin D supplement containing either 400 or 1000 IU vitamin D is appropriate. ---
**Author:** ![MuleSkinner](https://avatars.discourse-cdn.com/v4/letter/m/779978/32.png) [@MuleSkinner](https://boards.straightdope.com/u/MuleSkinner)\ **Post date:** [January 23, 2011, 4:12pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/22 "2011-01-23T16:12:38Z")
[New Guidelines for Vitamin D and Calcium](http://healthland.time.com/2010/11/30/government-group-issues-new-nutritional-recommendations-for-vitamin-d/) Snippet: > [@](#): > > That’s why the Institute of Medicine (IOM), an advisory group established by Congress, was charged by the U.S. and Canadian governments to gather the existing evidence on the health benefits of vitamin D and calcium, and come up with revised guidelines to help the public and the medical community determine the recommend dietary allowance, or RDA, of each nutrient. And according to the committee’s analysis, North Americans are not nearly as deficient in vitamin D as we have been led to believe. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [January 23, 2011, 4:57pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/23 "2011-01-23T16:57:03Z")
> [@bardos](#): > > Some medical folks are saying Vitamin D is not a vitamin, but a hormone. I am taking 4000 units per day D3. It is a quasi-hormone. It acts like a hormone and the body is able to synthesize vitamin D3 with the aid of sunshine (radiation). ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [January 23, 2011, 5:01pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/24 "2011-01-23T17:01:55Z")
> [@Northern\_Piper](#): > > is it true that lower levesl of Vitamin D may lead to more colds etc? There appears to be a strong association. > **[Vitamin D Levels May Be Linked With Recent Upper Respiratory Infection](https://www.medscape.com/viewarticle/588670)** > > In a population survey, serum 25-hydroxyvitamin D levels were inversely associated with recent upper respiratory tract infection, particularly in those with respiratory tract diseases. > [@](#): > > The investigators conducted a probability survey of the US population performed between 1988 and 1994 and evaluated the association between 25(OH)D levels and recent URTI in 18,883 participants 12 years or older, both with and without adjustment for demographic and clinical factors including season, body mass index, smoking history, asthma, and chronic obstructive pulmonary disease (COPD). > > Median serum 25(OH)D level was 29 ng/mL (interquartile range, 21 - 37 ng/mL). Recent URTI was reported by 19% of participants overall (95% confidence interval [CI], 18% - 20%), by 24% of those with 25(OH)D levels less than 10 ng/mL, by 20% of those with levels of 10 to less than 30 ng/mL, and by 17% of those with levels of 30 ng/mL or more (P \< .001). > > **Lower 25(OH)D levels were independently associated with recent URTI, even after adjustment for demographic and clinical factors (vs 25[OH]D levels ≥ 30 ng/mL: odds ratio [OR], 1.36; 95% CI, 1.01 - 1.84 for \< 10 ng/mL and OR, 1.24; 1.07 - 1.43 for 10 to \< 30 ng/mL)**. Among individuals with asthma and COPD, the association between 25(OH)D level and URTI appeared to be stronger (OR, 5.67 and 2.26, respectively). ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [January 23, 2011, 5:35pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/25 "2011-01-23T17:35:53Z")
> [@MuleSkinner](#): > > [New Guidelines for Vitamin D and Calcium](http://healthland.time.com/2010/11/30/government-group-issues-new-nutritional-recommendations-for-vitamin-d/) > > Snippet: Don’t fall for this. The very same IOM panelist who’s telling everyone we don’t need natural vitamin D is also a panelist for a pharmaceutical company that’s developing a synthetic version of vitamin D (you can’t sell sunlight for a profit). > **[Action Alert: Vitamin D Report Panelist Has Ties to Big Pharma | Alliance for...](https://anh-usa.org/action-alert-is-the-institute-of-medicine-in-bed-with-big-pharma/)** > > As we reported last week, the IOM’s new and absurdly low vitamin D recommendation flies in the face of scientific evidence. Now we need your help to get Congress to launch an investigation. > [@](#): > > **There is, unfortunately, a hidden agenda afoot. A pharmaceutical company is developing a patentable man-made vitamin D analog—yes, a synthetic drug version of vitamin D. And Glenville Jones, PhD, one of the committee members who determined the new vitamin D guidelines and who is quoted as saying that under these guidelines, most people “probably don’t have vitamin D deficiency” and “We think there has been an exaggeration of the public’s interest in vitamin D deficiency,” is an advisor for that same pharmaceutical company**. I can’t imagine a bigger conflict of interest than that. Astounding. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [January 23, 2011, 6:17pm UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/26 "2011-01-23T18:17:36Z")
> [@Surreal](#): > > Don’t fall for this. The very same IOM panelist who’s telling everyone we don’t need natural vitamin D is also a panelist for a pharmaceutical company that’s developing a synthetic version of vitamin D (you can’t sell sunlight for a profit). > > [http://www.anh-usa.org/action-alert-is-the-institute-of-medicine-in-bed-with-big-pharma/](http://www.anh-usa.org/action-alert-is-the-institute-of-medicine-in-bed-with-big-pharma/) > > I can’t imagine a bigger conflict of interest than that. Astounding. I’m not arguing but simply don’t understand. If Jones is saying that vitamin D deficiency is not as prevalent as commonly believed, wouldn’t that mean there would be fewer candidates for treatment with vitamin D or its analogues (i.e. his product)? If there was a conflict of interest, I’d expect him to be trying to _overstate_ the incidence of vitamin D deficiency in order to make more people possible users of his new agent. What am I missing? Thanks! ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [January 24, 2011, 12:56am UTC](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565/27 "2011-01-24T00:56:45Z")
> [@KarlGauss](#): > > I’m not arguing but simply don’t understand. If Jones is saying that vitamin D deficiency is not as prevalent as commonly believed, wouldn’t that mean there would be fewer candidates for treatment with vitamin D or its analogues (i.e. his product)? If there was a conflict of interest, I’d expect him to be trying to _overstate_ the incidence of vitamin D deficiency in order to make more people possible users of his new agent. What am I missing? Thanks! If they were to admit that vitamin D is effective and safe that might encourage people to get more sunshine (which is free) or to take vitamin D supplements (which are cheap). Vitamin D is not patentable so it’s difficult to make huge profits selling it. So they need to convince people that 1) natural vitamin D is _not_ therapeutic and 2) that their patented, synthetic, and probably outrageously expensive vitamin D analog actually _is_ therapeutic. Will it work? Probably. Just look at all the idiots taking Lovaza with its 5000% price markup. [Previous page](https://boards.straightdope.com/t/vitamin-d-what-is-it-good-for/568565.md?page=1)