Should I Take Vitamin D?

Updated: May 17

I have had many women come to my practice because they have irregular periods. Either periods are missing, they're longer than the recommended 34 day cycle, or they are heavy and painful.


In this article I cover the benefits of vitamin D, its effect on our monthly cycle, and how you can make sure you have an optimal vitamin D level.


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How does Vitamin D affect my period?


Vitamin D is important for many reasons. Without proper vitamin D levels, our body is not able to effectively absorb calcium and our immune systems become more vulnerable. But for our focus in this article is the link between vitamin D and our hormones.


Research has shown that there is a connection between menstrual cycle length and vitamin D levels. Studies found that low vitamin D levels (20-30 ng/ml) were present in twice as many women with longer cycles compared to women with vitamin D levels above 40 ng/ml. (1)

Low levels of vitamin D is linked with more painful periods, decreased fertility, and female pattern hair loss. (2),(3)


What level should vitamin D be at?

Most of the medical community agrees that levels above 20 ng/ml is sufficient. Functional medicine recommends a higher level of 50-70 ng/ml. The Vitamin D Council recommends maintaining serum levels of 50 ng/ml.

Vitamin D Rich Foods


Sunshine is the best way for us to get vitamin D, but unfortunately some of us are still unable to get adequate vitamin D. And for others (like myself) with fair skin we try to avoid too much sun because we don't want sunburn!


Alternatives to sunshine would be diet or supplementation. There are not many foods that contain vitamin D so supplementation is often the most consistent way to ensure adequate vitamin D.


Foods that contain vitamin D include:

  • Fatty fish (e.g. salmon, mackerel, sardines)

  • Cod liver oil

  • Grass-fed or Pasture-raised egg yolks and beef liver

  • Foods that have been fortified with vitamin D (e.g. milk, cheese, orange juice, cereal, and some non-dairy milk products)


Vitamin D Sunshine



Testing for Vitamin D Level


Vitamin D testing should be a blood draw. You can ask your doctor about ordering a test, or if you want to order your own test at wholesale cost you can order through Ulta Lab tests online.





It can feel like our body is working against us, but please know that is never the case!


If you're looking for additional guidance and support, let me know. Now is the time to invest in yourself and your body. You deserve to feel happy, energized, and comfortable in your body! Apply to work with me here


For tips, live videos, and to keep learning about nutrition and hormones, join my free online community!


Liz Riesen, Registered Dietitian

works specifically with women's hormones, inflammation, and digestive health. Often these conditions coexist and share common disruptive symptoms including bloating, weight gain, anxiety, mood swings, irregular cycles, and other inflammatory symptoms.

Liz is trained in identifying and healing food sensitivities, as well as balancing hormones naturally through nutrition and lifestyle. Follow me @moms.hormone.dietitian