The People's Perspective on Medicine

Study of Vitamin D Supplements Results in Disappointment

A study of vitamin D supplements demonstrated that these pills do not protect people from heart disease or cancer.

Millions of Americans are low in vitamin D, but taking vitamin D supplements may not do any good. A study of vitamin D supplements recently published in The New England Journal of Medicine (online, Nov. 10, 2018) showed that they do not protect against heart disease or cancer.

These results leave physicians and patients in a quandary. Research has shown that people who are deficient in vitamin D are more susceptible to rheumatoid arthritis, hypertension, asthma, diabetes, depression and osteoporosis. In addition, those who have more sun exposure and higher levels of this hormone in their bodies appear less susceptible to certain cancers and autoimmune conditions. They may also resist infections better.

Why Are People Low in Vitamin D?

If vitamin D is so critical to our health, why are so many people deficient? One reason is that we spend a lot of time indoors. Our skin makes this crucial compound when it is exposed to sunlight.

When we go outside in the sunshine, we are supposed to slather on sunscreen. Such products interfere with vitamin D formation, however. When asked about this, many dermatologists will tell you that you can always take a supplement to get your vitamin D.

Do Vitamin D Supplements Work to Prevent Problems?

Now, it looks as though taking vitamin D in pills may not actually provide the expected benefits. The VITAL clinical trial was a study of vitamin D supplements that recruited nearly 26,000 adults to take 2,000 IU vitamin D3 or look-alike placebo pills every day for more than five years.

The investigators reasoned that this dose of vitamin D should be enough to make a difference in circulating levels of the vitamin (which acts as a hormone in the body). And in fact, it was. In the volunteers who had repeat measurements of 25-hydroxyvitamin D, the levels increased by about 40 percent in those on vitamin D pills. They hardly changed at all in those who were taking placebo pills.

Big Disappointment from the Study of Vitamin D Supplements:

That’s why it is such a disappointment that there was no difference between the groups when it came to the important outcomes–invasive cancer and major cardiovascular events. In an after-the-fact analysis, the researchers found that if they didn’t include the first year or two years in the analysis, people taking vitamin D were about 37 percent less likely to die of cancer. This difference was significant, but the overall rate of death did not differ between the groups. There also did not appear to be any differences with respect to unpleasant reactions such as kidney stones, digestive distress or elevated calcium levels.

These eminent researchers conclude

“daily supplementation with high-dose vitamin D for 5 years among initially healthy adults in the United States did not reduce the incidence of cancer or major cardiovascular events.”

It is not entirely clear why this study of vitamin D supplements showed them to be so ineffectual. These results mirror those of several other randomized controlled trials over the past few years.

It leaves us wondering, however, whether the casual advice to simply take vitamin D pills instead of getting some sun exposure is really adequate. Of course, too much ultraviolet radiation can lead to sunburns, wrinkling and skin cancer. But moderate sun exposure might be more beneficial than most people think.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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This demonstrates how misperceptions happen.
The study was done to see what if any positive effects are observed on heart disease or cancer and none were observed.
Too many prople will read the article and extrapolate (inaccurately) that D3 is useless altogether.
I believe that my 87 year old mother-in-law is alive today because I had suggested she start taking D3 5000IU two years prior to her heart attack and quad bypass.
The article correctly reported on the study, I am lamenting how people misinterpret.
Thanks for your work!

Being an outdoor person and having a small nursery, I spend far more time in the sun than many people. However, when my blood was checked for Vit D, the level was 12 and should have been 33. It took almost a year to raise it to minimum level. I started research on drug induced vitamin/mineral deficiencies and found that several I had taken like PPI actually made it difficult to absorb D, or actually block it.

Most of us do not get nearly enough vitamin D, but taking the daily supplement vitamin D3 is not enough. In addition to getting blood levels up to around 40-60ng/ml 25OH-vitamin D (which usually needs at least 5,000 IU D3 daily), we also need to take the cofactor magnesium (either dietary or as a supplement), and daily vitamin K2 (the MK7 form, or eat some natto!). Vitamin D helps us absorb more calcium, but vitamin K2 tells the calcium where to go! Out of the arteries into our bones and teeth, helping both systems. Also remember to take some fat (like avocado or nuts) with fat-soluble supplements (such as vitamin D, K2, A, E; or fish oil).

Idk about cancer but it surely helped me with a muscle problem. I was on the toilet one day and all of a sudden my thigh muscles both clenched. It hurt, and from then on it hurt every time I sat down or got up. The doctor and chiropractor had no idea. I was going to go to a pain doctor when I saw an internet article and asked my doctor to check my Vitamin D levels. I was at 12%. She gave me a 50,000 unit pill which made me sick (actually threw up the next morning). So my Doctor told me to just take 5,000 units a day. In 4-6 months (I forget) the horrible thigh pain went away, and when I checked at 3 months I was at 67% Vit. D and rising. I had not been in the sun, drinking milk, nor even taking a multivitamin, at the time, so I guess there were good reasons why I was so low in it.

Well, according to Mayo Clinic, Vitamin D toxicity happens when you exceed 60,000 IU/day
I think some of these people haven’t got their act together yet…
Read Mayo report here;

I have been taking Vit D for years from October – March at a much higher rate than was used in the study. In my reading over the years and a Canadian study I read some time ago it was indicated that D level should be over 60 ng/ml to be effective. Another question I would have is why is the study focused on people 50 and over. Isn’t it more likely that underlying cellular damage/change would be present and beyond any benefit derived by Vit D? Also I wonder with all the focus on reducing cholesterol and aggressive use of sun block are we filtering so much Vit D that we are increasing the end point risks? Doesn’t cholesterol rise to skin surface and absorb D into our bodies?

Some doctors outside the USA are recommending to patience to take vitamin D as drops not capsules. I wonder if it makes any difference

Even if the supplemental vitamin D does not seem to provide the benefits sought, is it detrimental to your health if you take it daily? I was advised by a family friend physician to take vitamin D to help with bone growth after having my shoulder replaced.


That is like saying flour by itself has no affect on making bread. You need water and heat at a minimum. Vitamin D3 is a vital part of any supplementation regimen. adding Lysine and Proline to my regimen along with all cologen essential nutrients has had great results. No knee pain! Takes some time to get results though.

I’ve been taking daily 5,000 IU of vit D3 (which is classified as a hormone actually) for the last 26 years of my 69 yr life. test for vit D levels have been consistently in the upper range of normal and i’ve had no symptoms of overdose. all labs and diagnostic tests are normal, etc. Per family history, I should be well into late onset diabetes, cardio vascular issues, osteoporosis, hypertension and atrial fib. There are no indicators yet. i credit this to the vit and supplements including vit D I take as significant to my health. I suspect, like the caution to eat less eggs, coffee is bad for you et al, further research will reveal vit D is germane for good health: bones, cancer, heart, mood…perhaps the 2000 IU was not high enough? there could be all kinds of other issues impacting the research conclusions. etiology is so very difficult to tease out and understand. I think statement: “people taking vitamin D were about 37 percent less likely to die of cancer. This difference was significant, but the overall rate of death did not differ between the groups” needs to be explored – genetics? car crashes? preexisting conditions? suicide? other causes of death that Vit D would not be a factor?

There are other things that vitamin D helps. My overall good attitude about things are helped. I take it for energy help and depression rather than prescription drugs. Don’t give up on it yet. Also my mom used to give us cod liver oil in the winter to help us stay well. Doesn’t that help vitamin D to work well.

Living in the northern hemisphere (Seattle), I wonder how we can get an adequate amount of vit. D in our overcast & foggy 9 month long winters without taking a supplement. Doesn’t vit. D also protect bone loss? I’m 84 and my doc. recommended It when I was diagnosed with osteopenia several years ago. Am I pouring my money down a rat hole?

1. Not controlled for magnesium levels (probably all were deficient)
2. Dosage was too low for outcomes studied.

I went to the Amen clinic and was prescribed 10,000 units of vitamin D for my depression. Within 6 weeks I stopped taking Zoloft which I had taken many years with no depression returning. After I got my D3 blood levels up to 98 I dropped back to 5000 units which I now take regularly. I have never had to return to taking Zoloft and no longer suffer from chronic depression.

Since when the first year or two years were not counted, the last 3 years did show a 37% decrease in cancer mortality, might that indicate that Vit D must be taken over a period of at least that many years to have a beneficial effect?

Sun exposure isn’t always a replacement for vitamin D. As one ages, the ability to synthesize vitamin D from sunlight seems to decrease.

Case in point: I’m a male nudist in my early 70s. I never use sunblock. In 2016 I participated in a clothing-optional 8-day rafting trip through the Grand Canyon–eight full days of high-altitude (stronger) sun exposure. I followed this immediately with two weeks at a nudist resort where I never dressed. Shortly afterwards a blood test showed a vitamin D-25 Hydroxy level of 33.9 ng/mL, barely above the minimum level of 30.0.

I began taking 5000 IU of vitamin D daily. After six months the level was 66.4 ng/mL.

I like sunshine, but I guess that even an all-over exposure isn’t sufficient for me.

I don’t think these physicians/researchers are considering the many other benefits for Vitamin D. I, for one, have found it allows great relief from my IBS-D and it’s debilitating effects, as well as those side effects the IBS brings on such as mental fog and joint aches. In my “study”, I have found that many IBS-D sufferers in the online groups I am in, have found the same benefits as I have; and can tell when they may need to increase their Vit D intake due to increased bouts of diarrhea. I also live in a northern state so the sunshine is minimal during the Winter. I urge everyone to get their Vitamin D levels checked…it can mean a happier gut and a greater immune system.

What is the difference between Vitamin D and Vitamin D3?

Prevention of disease by supplements doesn’t happen overnight. It would take years of use of a vitamin or supplement to manifest any conclusion. Don’t be so quick to come to a conclusion. It is not like treating an infection or HBP where the results are more immediate. I don’t have a dog in this fight, but think long not short as regards conclusions.

I agree with you David…..I DO KNOW that Vitamin D is great for preventing the flu…..I was prescribed 30,000 IU
for three days before I went with a group of young kids. They were all sick at one time or another, and previous to the Vitamin D, I would’ve been the first one sick. The normal amount is between 2,500 and 5,000 IU, but I have since found out that some Doctors are using it to prevent the flu. I don’t know about heart or cancer, but I think it would be beneficial…..

If taking Vitamin D did increase Vitamin D circulating in the body, will that increase be helpful in preventing further decrease in bone density?

Leaving no stone unturned, researchers examine many possible benefits of VitD, and they say it does this or that. The findings could be due to chance. Maybe they have no idea how much is needed.

What about the benefits with protecting bones?

It looks to me like it is still worth taking the supplement. Especially if you live in areas with low sunlight. Bone strength is still very important.

I am battling squamous cell skin cancers. I really try to stay out of the sun.

I take Vitamin D supplements. But according to the research, it’s not going to help.

I also have osteopenia and was told that Vitamin D would help. I do walk anywhere from 15-20 miles a week at my job.

So, short of being in the sun, what else would help?

I think that most people cannot get enough Vitamin D from the sun. Doctors continue to tell people to only go out in the sun in the AM and slather on sunscreen if you go out in the afternoon. The truth is that UVB rays which are not present until the sun gets to a certain angle in the sky increase Vitamin D. However, they are only present later in the day and in most latitudes in North America for only for a short time. Going out in the morning only exposes you to more UVA rays which can cause skin cancer. This is the reason most of us are deficient in Vitamin D.

I struggle with low-normal vitamin D levels and plunging bone density scores as a result of menopause and medication: many years on levothyroxine and 4.5 years on an aromatase inhibitor (Breast cancer, triple positive). I don’t tolerate standard calcium supplementation, and adding OTC vitamin D seems to cause higher than acceptable calcium level in my blood.

Any thoughts about an algae supplement called Algaecal? I’m getting targeted marketing on line. They cite studies but it’s quiet expensive and according to them most beneficial when taken with their proprietary vitamin supplement blend. Sigh. Help! Anyone’s thoughts or experience with this would be helpful.

There is research in animals (especially mice) demonstrating that the alga Lithothamnion can strengthen bones. Clinical research in humans is limited, and Algaecal might not be the only product that contains this alga.

The question that comes to mind is: How was the vitamin given, and what was the diet of those taking the vitamin. One vitamin is, and will never be, a cure all. You are what you eat, over all.

As far as getting it from the sun: Well, with this chemical haze I see every day over NC, how is it possible to get D from sunshine?
I took pictures of a true dark blue sky after a hurricane. Dark blue and with fluffy normal clouds.

What about Vitamin D for fibromyalgia and psoriasis?

More studies needed on both those conditions. Here is the latest on psoriasis. It is inconclusive:

I asked my Dermatologist what he thought about the results of this study. He said that he was surprised that vitamin D was not more protective. He ended by saying that vitamin D was relatively cheap, and he planned to continue taking a 1000 unit supplement daily.

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