by Marion Nestle
Nov 30 2010

IOM: vitamin D, calcium supplements not needed!

In a report likely to send shock waves through the dietary supplement industry, the Institute of Medicine (IOM) released new Dietary Reference Intakes for vitamin D and calcium.   The report summary says Americans are getting all the vitamin D and calcium we need, and we do not need more.

The committee emphasizes that, with a few exceptions, all North Americans are receiving enough calcium and vitamin D. Higher levels have not been shown to confer greater benefits, and in fact, they have been linked to other health problems, challenging the concept that “more is better.

In an account of the report in today’s New York Times, Gina Kolata writes that the committee was puzzled about how vitamin D became the hot nutrient of the year.  Sales rose 82% from 2008 to 2009.

Some of this surely had to do with testing.  A method for testing existed, so doctors used it.  The test, however, looked at an intermediate in vitamin D synthesis—not at the vitamin itself.  And the test did not have a standard until recently.

And groups like the Vitamin D Council promote much higher intakes of vitamin D supplements.  According to the Council:

Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.

In my San Francisco Chronicle column on this topic a year or so ago, I pointed out that “vitamin” D is not really a vitamin.  It is a hormone. This means that vitamin D supplements are a form of hormone replacement therapy—not necessarily a good idea.

Are vitamin D supplements needed?  Not if you expose your skin to sunlight for a few minutes a day, even in winter.

Comments

I think the doc in this cartoon states the case very well: http://bit.ly/dGZUjH

[...] This post was mentioned on Twitter by Marion Nestle, Helen Branswell, Barry A. Martin, Erika Nicole Kendall, Heather Stryk and others. Heather Stryk said: @choosingraw I feel like I got the complete opposite message via Food Politics about Vitamin D http://trunc.it/cxi35 [...]

  • Uncle Herniation
  • November 30, 2010
  • 10:19 am

Even in winter?

It depends on where you live. Go outside in NYC right now, and you will be exposed to a UV Index of 1. A UV index of 3 is necessary for the skin to be exposed to 270–300 nm wavelength UVB light. That is how Vitamin D is made. You could stand out there all day and not have any Vitamin D manufactured.

  • Melissa
  • November 30, 2010
  • 10:20 am

I did 15 minutes a day of outdoor exposure last winter and when I got the test for D levels in the spring I was very low. Is the test really flawed? Then is there another way to know if my levels are OK?

  • Anna
  • November 30, 2010
  • 10:44 am

I live in the northern USA, when it is cold in the winter I am mostly covered up and I am sure that I do not get direct sunlight every day in the winter. At my last check up, my doctor told me I should take vitamin d supplement. She did not even test my levels, just said that people aren’t getting enough vitamin d, so I should take a supplement. I’ve taken it sporadically, but it seemed like she read a study and then told me that is what I should do. It so hard to know what to do with all of these studies. I want to be healthy, but this information can be very confusing.

I agree with the previous comments. The combination of sunscreen and latitude really reduces the sun as Vitamin D source. It’s very hard to eat the amount of vitamin D we need and while we shouldn’t megadose, supplementation for many doesn’t seem like a bad idea.

  • Anthro
  • November 30, 2010
  • 12:00 pm

Could someone give a straight answer to the question of exposure to sunlight in Northern climates. How much skin needs to be exposed? Is light enough or need it be SUN light? Is 15 minutes with only a bit of ones face exposed enough? Does sunscreen interfere with this? My moisturizer has SPF 15 in it and I use it every day without thinking; should I walk for 15 minutes before applying the stuff?

I’ve been taking minimum supplement for about a year now, but am thinking I should only do so in the winter–if at all, but some days in winter, I do not get more than five minutes outside with very little skin exposed. I think this is common for a lot of people who live in the Northern US. I don’t use much dairy, so that’s why I started the supplement. It seems there might be a lot of individual factors and more information needs to be given. I know the study applies to the general population, but people are bound to be concerned about their own personal circumstances. I don’t think it’s enough to ask one’s doctor–they cannot be up on all the studies and know if the methodologies are good in all cases. Doctors are science-trained, but not primary researchers and many are not going to argue with people–even if they are doing all kinds of supplementation and other “complementary” practices.

  • B.
  • November 30, 2010
  • 12:03 pm

That’s exposure to sunlight WITHOUT sunscreen.

  • Renee
  • November 30, 2010
  • 1:09 pm

Medical advice can change with the wind, it seems. My vitamin D levels tested deficient, and I’ve been supplementing throughout the winter months for several years. I often get no direct sun at all during the winter, so I’ll keep my supplements going for now.

Well, I’m not sure how much credence to place in this report. It seems like nutritional advice is very trendy- veering in one direction and then another. I DO know that I make it a point to consume 1200 mg.day calcium from the food I eat (dairy, leafy greens, almonds, canned salmon w/bones etc), plenty of K (radishes etc), and I DO take a 1000 IU/day Vitamin D supplement and have done so for a couple of years. And- I DO believe this regime is bone protective. I am 67, ride my bike about 50 miles/week or more and unfortunately, fall off it 2-3 times a year. Knock on wood…. so far, so good. So, I’ll stick to what seems to be working for me, thanks.

  • Kelly
  • November 30, 2010
  • 2:33 pm

One hand appears to not be talking to the other. I mean, the report is saying “sure, as long as you get enough exposure to the sun without sunscreen” – forgetting that they tell people to not go outside without sunscreen for more than a few minutes a day. (And on top of that, forgetting that some folks live in areas where the sun is a mighty fine memory for a good part of the year.)

The report also says that people eat enough fortified foods to get all the excess supplements they need – but isn’t this the same group that says folks should avoid pre-packaged, fortified foods and instead eat things you prepare yourself (thus skipping out on the fortified bit)?

Yeah. I think this is a problematic report, to say the least.

  • Cathy Richards
  • November 30, 2010
  • 2:52 pm

Even in winter?
UV index of 3?

It depends entirely on your lattitude and the seasons.

In the winter, in Canada & Alaska, the sun has to pass through more atmosphere than it does in the summer. The atmosphere filters out more UVB than UVA. In the winter, in Canada, enough UVA gets through that you can still sunburn, so the UV index may still be high.

However, UVB rays — the ones that help us make vitamin D — cannot get through in sufficient quantity so that even being outside naked on the sunniest day we cannot make adequate vitamin D in our skin to meet our needs. UVA rays have nothing to do with vitamin D production.

The months during which insufficient UVB gets through to us depends on your lattitude.

Kamloops, British Columbia @ 52 degrees latitude: No vitamin D produced from October to March

Boston, MA @ 42 degrees, is November to February.

  • Cathy Richards
  • November 30, 2010
  • 3:08 pm

PS. I oversimplified the lattitude issue. It’s really thickness of atmosphere, which isn’t directly related to lattitude once you get closer to the poles.
But basically, the report says that from October to March North Americans can’t count on sun synthesis to meet their vitamin D requirements.

What if you become an obsessive sun tan lotion user? I’m a firm believer that you can get all the vitamins and minerals you need from a balanced diet/lifestyle alone, but I’ve been reading all year about vitamin D deficiency becoming an issue across America. Am I just being brainwashed to buy vitamin supplements? By doctor even told me I should probably start taking one.

  • Kate
  • November 30, 2010
  • 5:17 pm

Maybe it was a mighty strong placebo effect, but I started taking vitamin D last winter on my doctor’s recommendation and felt better within days – way more energy, less groggy. I was an otherwise very healthy triathlete that found myself hardly able to work out last winter. Besides, I live in MN. Most days I’m not sure which patch of skin I would like to expose to the winter freeze. 5 minutes is a long time some days.

  • Nuc Sub Vet
  • November 30, 2010
  • 5:27 pm

I tested low last year, I live on the central coast of CA and get sun, although sometimes not 15 minutes. I also have arthritis. My Rheumy prescribed 50,000 units, (that is 50,000 units) twice a week. I researched a lot and told her I thought this was too much. She said I was low on my vit d test. My regular doc never mentioned this.

I told my Rheumy that I thought it was too much and she said ok go down to once a month. By the way this amount of vit d is a very expensive medication not on my formulary.

I now take a regular multivitamin and don’t think I’ll be taking huge doses of vit D.

  • Tony K
  • November 30, 2010
  • 6:11 pm

Nuc Sub Vet

That amount of D is a pretty common prescription for Vit D2. Vitamin D3 requires much lower levels. Costco sells a pretty good oil-based D3 supp with 2000 iu.

If you take one of those per day in the winter, it probably wouldn’t hurt. Do get your Vit D levels checked first though to ensire that you are low.

I did a post on Vitamin D tests a while back http://www.emotionsforengineers.com/2009/10/which-vitamin-d-test-to-get-25-hydroxy.html

Regards

  • Sarah G
  • November 30, 2010
  • 9:03 pm

I’m glad that they’ve clarified that we don’t need mega doses of Vitamin D. But because I don’t eat like “most Americans” (I’m lactose intolerant and eat mostly unprocessed foods that aren’t fortified) I am going to continue to supplement. I think people should only stop supplementing if they eat the Standard American Diet.

  • Eric E, MS RD
  • November 30, 2010
  • 10:04 pm

This statement from the Conclusion of the Summary of the Report is inconsistent with the actual report: “the committee emphasizes that, with a few exceptions, all North Americans are receiving enough calcium and vitamin D.”

The report recommends an Estimated Average Requirement of 400 IU and 600 IU RDA (for most adults). However, the report says that “the median intake for males ranges from 272 to 396″ less than the EAR. For females, intake from food ranged between 160 and 260, again much lower than the EAR without supplementation. With supplementation the numbers still do not meet the EAR let alone the RDA. For women over 70 in particular, for whom the RDA is higher at 800 IU, the findings were that the median intake with food AND supplements reached a median of only 356 IU. Food alone for this group only accounted for 160 IU. Clearly, without supplementation, the amount would be dramatically inadequate. We don’t need megadoses. But supplementation appears necessary to reach adequacy, especially in the older population.

The conclusion from the Summary does not make sense given these numbers which indicate Americans need to intake more vitamin D than they currently do. It is the wrong sentence from which to draw headlines.

  • Subvert
  • December 1, 2010
  • 12:58 am

Gosh, what did my grandparents and other ancestors do without all this information and dietary influence? I am amused by all the seemingly urgent ‘am I getting my vitamin D, or not?!’ banter. I guess we all have to have something to obsess on in this incessant life we are surrounded by…

  • Jill
  • December 1, 2010
  • 6:04 pm

This study looked at what was adequate for BONE health. It does not address the importance of higher vitamin D levels for proper IMMUNE SYSTEM health. I’ll stick to taking a supplement here and there in the winter months.

  • Cathy Richards
  • December 2, 2010
  • 5:09 pm

@Subvert
– some of your grandparents would have bow-legged friends that experienced rickets as children.
–And since the average life expectancy at the turn of the 20th century was 47, not many people lived long enough to get osteomalacia (like osteoporosis, but caused by lack of vitamin D, vs lack of calcium).
–your grandparents likely got a lot more sun exposure, in days without sunscreen, and didn’t live in cities with high rises that shadowed kids playing in the streets.
-if your grandparents are white, it’s relatively easier for them to make vitamin D in sunlight at our latitudes. The ethnic mix of North Americans is much different now and on average we need a longer time exposed to the sun to make adequate vitamin D.

Although it’s romantic and nostalgic to look back to simpler times, the health practices weren’t necessarily better. Pre-formula, babies who weren’t breastfed had a high risk of illness and death from drinking cow/goat milk. Unpasteurized milk could result in typhoid, tuberculosis, and many g.i. infections. Sewer systems were inadequate and resulted in diseases. Smoking was everywhere. People died from smallpox, were paralyzed or killed by polio.

I dunno. Our health isn’t great now, but I don’t want to look backwards except to learn lessons.

  • Cathy Richards
  • December 2, 2010
  • 5:13 pm

@Jill — yes, they did look at the role of vit D beyond bone health. They could not find adequate numbers of well designed studies to justify changing vit D recommendations based on the many other diseases they looked at (MS, cancer, heart disease, depression, etc). The report states clearly that other chronic diseases will be continued to be examined — they clearly recogninze the potential role but could not recommend an increase in a hormone (vitamin D is more like a hormone than a ‘vitamin’) based on inconclusive evidence.
Thus, the changes in recommendations could only be based on bone health.

  • Tony Sheehy
  • December 4, 2010
  • 5:21 am

While I have the greatest regard for Marion’s opinions on virtually everything she writes about, in this instance I am surprised at how on the issue of vitamin D she has ignored the absolutely critical issues of latitude and ethnicity. Wherever this advice that ‘a few minutes a day of sunlight exposure is OK, even in winter’ is written for, it certainly does not apply above 35-40 degrees, latitudes above which hundreds of millions of people around the world live.

I live in Cork, Ireland, at about 51.5 degrees N, and colleagues of mine (Cashman et al. (2008) Am J Clin Nutr. 88(6):1535-42) have shown that depending on what level of serum 25-OH D is selected as the cut-off point for deficiency, a minimum of 7 mcg and in fact anything up to 42 mcg/d of vitamin D intake is required in Ireland to maintain adequate vitamin D status in wintertime. The modern-day Irish diet is insufficient, containing only about 3-4 mcg vitamin D on average. The reduced efficiency of vitamin D synthesis on skin by both the elderly and people with darker skin pigmentation are additional factors that have to be taken into account.

To get a more comprehensive perspective on the vitamin D situation in the modern world based on current evidence I highly recommend this video featuring Dr. Michael Holick of Boston University School of Medicine.

Vitamin D and Prevention of Chronic Diseases
http://www.youtube.com/watch?v=Cq1t9WqOD-0

It’s interesting and entertaining, and you will come away realising that when it comes to vitamin D, things are a lot more complex than those who say ‘a few minutes a day is OK’ would lead you to believe.

  • Roxanne Rieske
  • December 8, 2010
  • 3:24 pm

What a bunch of crock from the IOM. They need to be beaten over the head w/ this report and sent back to the classroom. I have a family history of various types of skin cancers, including melanoma. There is no way in hell I’m going outside for even five minutes without my skin being protected. There’s also the fact most of North America doesn’t receive adequate sun rays in the winter for our bodies to produce enough Vit. D. And what about the growing body of research that shows Vitamin D does much more for the body than protect our bones, and that the government RDA for vitamin D is highly inadequate?

  • Jon
  • December 13, 2010
  • 1:41 pm

Yeah, vitamin D’s a hormone, and unless you’ve got really dark skin and live really far up north, it’s not really a problem.

[...] isn’t a strictly accurate review of everything covered in the IOM report.  It seems that a San Francisco Chronicle columnist was certainly convinced although I am concerned that they think we get enough Vitamin D from sunlight, even in the [...]

[...] Vitamin D is not shown because you won’t get any from bananas, beans, or foods that aren’t fortified. But you can get Vitamin D for free (yes, free) from the sun. [...]

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