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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Endometriosis and vitamin D: Is there a link?

Endometriosis, defined as the presence of the inner lining of the uterus in places it should not be, affects up to 10% of reproductive-age women. It causes intense pelvic pain during periods (dysmenorrhea), pain during intercourse (dyspareunia), chronic pelvic pain, irregular bleeding and infertility.

A 2007 Italian study found higher vitamin D levels in women with endometriosis than in unaffected controls. The odds ratio for endometriosis in patients with 25(OH)D levels exceeding the 75th percentile of the serum distribution was 4.8. That is, they found women with 25(OH)D levels above 27 ng/ml were almost five times more likely to have the disease than were women with the lowest 25(OH)D level. The authors also found evidence of a direct gradient; the higher the 25(OH)D, the worse the endometriosis.

Somigliana E, Panina-Bordignon P, Murone S, Di Lucia P, Vercellini P, Vigano P. Vitamin D reserve is higher in women with endometriosis.  Hum Reprod. 2007 Aug;22(8):2273-8.

The authors mentioned that two other studies found no relationship between 25(OH)D and endometriosis. They also pointed out that African Americans have a reduced incidence of endometriosis compared to Caucasians. I could not find any latitudinal or seasonal studies.

This year researchers at Harvard studied 1,385 cases of incident laparoscopically confirmed endometriosis in women in the Nurses’ Health Study.

Harris HR, Chavarro JE, Malspeis S, Willett WC, Missmer SA. Dairy-food, calcium, magnesium, and vitamin D intake and endometriosis: a prospective cohort study. Am J Epidemiol. 2013 Mar 1;177(5):420-30.

They found that women consuming more than 3 servings of total dairy foods per day were 18% less likely to be diagnosed with endometriosis than those reporting 2 servings per day. In addition, predicted vitamin D blood levels showed women in the highest quintile had a 24% lower risk of endometriosis than women in the lowest quintile (P = 0.004).

That is, they found just the opposite of the Italian study.

This month Lebanese scientists reviewed the role of vitamin D in endometriosis and concluded randomized controlled trials of vitamin D supplementation in endometriosis are needed.

Sayegh L, Fuleihan Gel-H, Nassar AH. Vitamin D in endometriosis: A causative or confounding factor? Metabolism. 2014 Jan;63(1):32-41.

Besides elaborating on a mechanistic model in which vitamin D may help quell inflammation, the Lebanese authors pointed to a randomized controlled trial of vitamin D in dysmenorrhea, which is the pain during menstrual cycles that is the hallmark of the disease.

Lasco A, Catalano A, Benvenga S. Improvement of primary dysmenorrhea caused by a single oral dose of vitamin D: results of a randomized, double-blind, placebo-controlled study. Arch Intern Med. 2012 Feb 27;172(4):366-7.

In this pain study, 20 women received a single oral dose of 300,000 IU five days before their expected menses, comparing them to 20 women getting placebo. They found a 41% reduction in the mean pain score in the vitamin D treated women (p < 0.01). The greatest reduction of pain scores was noted in women with severe pain at baseline. We covered this study in detail in the past.

What does all this mean?

For me, it means the current literature does not support a randomized controlled trial of vitamin D in treating endometriosis. Before that occurs we need case reports to see if there is evidence of a treatment effect or an ill effect. If case reports indicate vitamin D helps, then an open label trial is in order.

Have any readers with endometriosis found vitamin D is helpful? Have any readers found it makes endometriosis worse?

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

17 Responses to Endometriosis and vitamin D: Is there a link?

  1. Rita and Misty says:

    How do “case reports” differ from anecdotal evidence? Would my comments here be considered a case report?

    I do have comments, but I wonder due to some very personal aspects of this disease if this blog is an appropriate venue. As open as I am, some things are still very personal to me.

    VDC: I must commend you on your excellent selection of graphics. In my opinion, they greatly enhance the blogs on your site. This puzzle piece..it speaks to how we each fit into the vitamin D community. But let’s remember, puzzle pieces are static. We, as human beings, have the wonderful ability of reacting and changing and growing and expanding….whether we are 10, 30, 50 or 65 years of age….(or older).

    John, I think this blog might make a nice VDC FB post.

    Be well,

  2. Rita and Misty says:

    Endometriosis is truly a life-hijacking condition.

    If there are female members of the Vitamin D Council who suffer from this condition, and would like to talk with me, I am okay with the Vitamin D Council providing my phone info to them.

    I do not wish to be contacted via email to discuss my condition, or my methods of self-treatment.

    I am not a physician, nor am I a healthcare professional–Just someone who has had way too much pain and decided to try to self-prescribed methods of treatment (including vitamin D3).

    John, the reason I asked for this blog to be posted on the VDC FB page is that I am open to having VDC FB readers also contact me.

    No woman should suffer from this condition.

    Brant and Jeff–I apologize if this causes any additional work for you. Only a small percentage of women suffer from this condition, so I doubt that you’ll be inundated with emails or calls. But, if VDC feels that this is inappropriate in any way, shape or form–please feel free to delete this posting. I won’t take offense. I don’t know how!

    I will share this much with everyone: copious amounts of magnesium will not help with endometriosis if you are vitamin D deficient. This has been my personal experience.

    We heal by helping. So I am open to phone calls on this matter. From women who suffer from this condition.

    Be well, Rita

  3. Endometriosis is associated with low vitamin D – 67 year literature review – Oct 2013
    There are also 34 other studies which mention Endometriosis on VitaminDWiki

  4. Rita and Misty says:

    Is endometriosis an autoimmune disease?


    “These observations suggest that endometriosis is associated with abnormal polyclonal B cell activation, a classic characteristic of autoimmune disease.”

    My apologies that I cannot link to full text here…but VDC should be able to get the full text article.

    I think vitamin D might be beneficial with respect to autoimmune disease. I think I read that some place. 😉

    BTW–this article was written in 1987. That’s a long time ago. That’s many, many, many painful months, for some women (and those they live with)….but, not painful for me any longer…. 😉

  5. Rita and Misty says:

    If you have one autoimmune disease, does it make you more susceptible to having another?

    Are diseases like MS, Lupus, endometriosis, hashimoto’s disease, etc. really a cluster of diseases stemming from one root cause?

    Can all autoimmune diseases be tied into vitamin D deficiency?

    The studies currently don’t tie in vitamin D deficiency to all autoimmune disease.

    But perhaps that is because “deficiency” hasn’t been properly defined.

    Maybe those who suffer from autoimmune disease(s) require a much higher 25(OH)D level for their bodies to be healthy.

    Perhaps a level closer to 100 ng/ml is necessary for those who suffer from autoimmune disease.

  6. Rita and Misty says:

    My apologies..I must have missed this blog back in April.


    Professor Munoz, “Considering these robust epidemiological data, one might believe that vitamin D deficiency plays a pivotal role in the multifaceted (cause) of autoimmunity that deserves further scientific research to pinpoint the mechanisms of action of vitamin D in the phagocytosis (eating) and clearance of dying cells.”

  7. Ian says:

    The recent article in In Vivo as posted on vitamindwiki is ascerting that vitaminD deficiency does underlie the conditions that initiate so-called autoimmune diseases.


    One you did miss out of list is ME/CFS a much misunderstood and medically maligned illness which is quite clearly an “auto-immune disease”. Without doubt if you read the FULL and recent literature.

  8. Rita and Misty says:

    Thank you, Ian. vitamin D, iodine, boron, zinc, magnesium, selenium and K have changed my life (for the better). Also, potassium.

  9. fredglass says:

    What is your experience with potassium supplementation? What form & how much? Also with Boron? ( I notice that the D3 I use has 9mg/5,000iu boron as a co-factor) Thanks. Fred Glass

  10. Rita and Misty says:

    400 mg Potassium daily

    9 mg Boron is fine

    Look into Iodine and Selenium.

    We live in a toxic world.

  11. Rita and Misty says:

    Potassium citrate…some find it hard on the stomach..I do not.

    Of course getting your Potassium from veggies and fruits is preferred.

    But, i have been known to take a supplement (or two) 😉

  12. Ian says:

    I mix the potassium citrate with my magnesium citrate, giving me 400mg magnesium and 100 mg potassium per dose, taken twice daily. I also use potassium chloride which I mix with standard salt (sodium chloride) 60:40 for general use in cooking and salting meals such as tomato.

    My serum potassium and sodium levels were recently tested and were bang-on.

  13. fredglass says:

    Rita & Ian:
    Thank you very much for your input. Something for me to experiment with.
    Thanks. Fred Glass

  14. Rita and Misty says:

    400 mg is a good amount of magnesium. some say transdermal absorption is better for magnesium. 100 mg of potassium a day is good if you eat a healthful diet. Otherwise it is too low. Aim for 400 mg of potassium a day from all sources. Good luck with that. Our soils are heavily depleted.

  15. Half of all my endometriosis patients are significantly better on a gluten free diet, most are not celiacs. So they are prone to many deficiencies – vit D, zinc, magnesium, folate etc etc

  16. Rita and Misty says:

    Margaret: I’m certain it is more complex than I am about to make it sound..yet I always wonder if Celiac disease is really bromide toxicity or iodine insufficiency…

  17. I believe that I have an explanation of why one or more studies have shown a slightly higher level of 25-hydroxyvitamin D in women with endometriosis compared to those without endometriosis.
    First of all, it should be noted in the study that even the women with endometriosis still had relatively low vitamin D levels, many near 27.
    So what would explain the connection? Several decades of experience in a primary care medical practice, AND reading medical research, has taught me that endometriosis is correlated with dairy intake. In practice I have questioned every woman with the condition about her dairy intake and have found the connection to be striking. I stress i didn’t make up this connection, there is supportive research that lead me to investigate this.
    Although dairy products don’t raise vitamin D levels to ideal levels, a high intake do in fact raise the vitamin D levels somewhat. Frequently over 27 ng, such as in the study. So the increase in endometriosis is not due to a higher vitamin D level, it is due to the years of high dairy intake. As far as why dairy has this effect, it’s a complex incompletely understood problem, but certain dairy as the source of hormones has been studied, and endometriosis is thought to be due to excess estrogen.
    I sympathize with any woman who suffers from this condition and my comments should not be interpreted by anyone as an effort to put the blame on the sufferer. Dairy has been promoted for many decades as health food and I am just one of the millions who believed it for a long time.

    Robert Baker MD
    Primary Care Internal Medicine