New Use for Vitamin D: Reducing PMS Pain

Yes, we know this vitamin has become controversial.  Just when researchers were beginning to give up on D as the wonder-vitamin, a new study comes along that provides a good reason at least not be to deficient in the vitamin that comes from sunshine.

In the study (published in the Archives of Internal Medicine and conducted in Italy) women who took vitamin D experienced a 41% decrease in menstural cramping (known as dysmenorrhea) based on a standardized, self-reported scale of pain.

Even more impressive, none of the women who received Vitamin D chose to take non-steroidal anti-inflammatories such as Motrin or Advil, but a full 40% of the women who received the placebo opted to take such pain-relieving pills during the study.

Amazingly the editorial in the stodgy Archives of Internal Medicine was uncharacteristically enthusiastic in its support of Vitamin D: "Encouraging all women to obtain the recommended dietary allowance for vitamin D (600 IU/d for women of reproductive age), as well as screening for low serum 25(OH)D levels among women with other risk factors for vitamin D deficiency, would be a rational interim approach." The editorial also called for more studies evaluating the impact of taking more than the recommended daily allowance.

It's important to note that the women in the study (all 18-40 years old and in good health) had serum D levels in the bottom 25% of normal. So they were low on D to begin with.  They were given one very high dose of a Vitamin D precursor (cholecalciferol, 300 000 IU/1 mL) which the body converts to Vitamin D as needed in order to bring their levels up to the high-normal range. Those who had the most dramatic decrease in pain had also reported the highest levels of pain at the beginning of the study. 

The study also shed some light on why Vitamin D would reduce menstrual pain. Vitamin D has been shown to regulate production of prostaglandins, messenger molecules responsible for smooth muscle contractions. Interestingly, Advil and Motrin do the same thing. In addition, Vitamin D is known to reduce levels of pro-inflammatory cytokins (immune molecules that cause inflammation), which is another duty performed by Advil, Motrin and their pharmaceutical cousins.

The take-away is to make sure to get the recommended daily allowance of Vitamin D, especially during winter months of low sun exposure.  And the next time you get a blood-test, ask your doctor to measure the level of serum 25 (OH) D. If you are low, or even below normal, then supplmentation with more than the daily allowance may very well help reduce menstural cramps.