Bacterial vaginosis Patient friendly summary

  • Solar UVB light produces vitamin D, which may reduce bacterial vaginosis risk.
  • Vitamin D may produce proteins that combat bacterial and yeast infections.

Bacterial vaginosis (BV) is the imbalance of bacteria in the vagina.

This occurs when there is an overgrowth of certain bacteria.

Symptoms include discharge, odor, pain, itching, or burning.

Risk factors

Risk of bacterial vaginosis involves a complex relationship between many factors:

  • Bacterial vaginosis-related pathogens: Bacteria, fungus, and/or yeast
  • Healthy vaginal microbiota: Organisms that protect the vaginal from imbalance and infection
  • Bacteriophages: Viruses that infect bacteria
  • Immune response: How well the body can fight infection

Non-pregnant women, especially blacks, are at risk if they:

  • Douche
  • Smoke

Oral contraceptives may reduce risk of bacterial vaginosis.

Sunlight exposure and bacterial vaginosis risk

There are no reported studies directly linking sunlight and geographic location to variation in bacterial vaginosis risk.

However, researchers in Pennsylvania found some evidence that bacterial vaginosis risk varies seasonally. Pregnant women enrolled in the study during winter and summer had low rates (35%) of bacterial vaginosis during the first 16 weeks of pregnancy. Higher rates (45% to 52%) of BV were noted for those enrolled in the spring and fall. The lower rate in winter is puzzling.

Vitamin D and bacterial vaginosis

Vitamin D levels

Two studies suggest a link between vitamin D levels and bacterial vaginosis rates:

  • In a 2007 study, African-American women with higher vitamin D levels had a lower risk of bacterial vaginosis. No correlation was found for white women.
  • In a U.S. study of pregnant women, low vitamin D levels corresponded with a higher bacterial vaginosis risk.

How vitamin D works

To counter bacterial vaginosis, vitamin D produces cathelicidin and defensins. These proteins fight bacterial and yeast infections. They may also neutralize bacterial toxins. According to several studies, there are increased concentrations of defensins in vaginal fluids during BV.


There have been no reported studies using vitamin D to prevent bacterial vaginosis.

However, vitamin D reduces the risk of other bacterial infections. It is very likely that keeping vitamin D levels above 30–40 ng/mL (75–100 nmol/L) might significantly reduce the risk of bacterial vaginosis, at least during pregnancy.

However, black women have lower vitamin D levels and a higher risk of bacterial vaginosis. Those who are not pregnant may benefit from higher vitamin D levels.


Vitamin D may be useful for women with bacterial vaginosis, especially when used in combination with antibiotics. Continuous vitamin D supplements or more exposure to natural ultraviolet-B (UVB) light should prevent a relapse.

Find out more...

We will be adding a detailed evidence summary on this topic in the near future.  Please check back soon to find out more.

Page last edited: 17 May 2011