Let's Talk Vitamin D and Birth Control Pills
New research reveals potential connection between vitamin D levels and contraceptive effectiveness
Vitamin D, famously known as the sunshine vitamin, plays a pivotal role in maintaining the right balance of calcium and phosphorus in the body. It assists in the absorption of calcium, an essential component of our bones. Food sources such as fish, eggs, and sunlight (yes, sunlight!) account for most of our vitamin D intake.
However, many of us fall short, and not just because of our diet—around 90% of our vitamin D comes from sunlight. A deficiency in vitamin D can lead to health issues like rickets, softening of the bones, and other bone problems, making it crucial, especially during pregnancy when bone development for both mother and baby is at stake.
Dr. Quaker E. Harmon of the National Institutes of Health's National Institute of Environmental Health Sciences wanted to delve deeper into whether oral contraceptives might affect vitamin D levels.
Vitamin D and Contraception: A Surprising Connection
To get some insights, Dr. Harmon analyzed data from the Study of Environment, Lifestyle, and Fibroids (SELF). This study involved nearly 1,700 African-American women aged between 23 to 34 from Detroit, MI. Dr. Harmon asked the participants about their contraceptive use and outdoor activities, any vitamin D supplements they were taking, and their blood samples were tested for 25-hydroxy vitamin D levels, the most common circulating form of vitamin D.
The findings suggested that women who were using contraception containing estrogen typically had higher vitamin D levels than others. Even after controlling for factors like seasonal sunlight exposure, the effect remained significant. It was noticed that current users of birth control had increased vitamin D levels, while past users showed average levels.
Dr. Harmon explained, "Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women." But how does this work? Well, we don't exactly know yet. Further research is required to answer this question, but it's thought that there might be alterations in the metabolism of vitamin D due to estrogen.
The Impact on Pregnancy
As women plan to conceive, they need to be mindful of their vitamin D levels. Given that estrogen-based contraception may increase vitamin D levels, they might run the risk of becoming deficient once they stop using birth control or during pregnancy. Dr. Harmon recommends ensuring vitamin D levels are adequate while trying to conceive and during pregnancy.
The research does not specify whether the same effect occurs in women of different races. However, considering African-American women are more likely to be vitamin D-deficient, small increases or decreases in their vitamin D concentrations may have more impact.
In Summary
Estrogen-based contraceptives seem to affect vitamin D levels by influencing vitamin D metabolism and its binding proteins. This may not always reflect in total vitamin D levels but may pose the risk of functional vitamin D deficiency. Clinicians should be aware of this relationship and maybe consider assessing bioavailable vitamin D levels in women using or discontinuing estrogen-based contraceptives around the time of conception. Keep in mind that more research is needed to understand how contraceptives interact with vitamin D levels.
[1] Hormonal contraceptives increase levels of sex hormone-binding globulin (SHBG) and other binding proteins, which can affect vitamin D status indirectly by altering hormone homeostasis and liver function.
[2] Estrogen can impair estrogen metabolism and gut microbiome balance, potentially affecting nutrient absorption, including that of vitamin D.
[3] Adequate vitamin D is crucial for maternal and fetal health during early pregnancy. Underdiagnosing deficiency due to the influence of estrogen-based contraceptives on vitamin D binding proteins can have adverse effects on pregnancy outcomes.
[4] Estrogen also stimulates the production of vitamin D binding protein (DBP) in the liver, which binds circulating vitamin D metabolites, potentially reducing the free (active) vitamin D fraction.
[5] Estrogen may impact gut microbiome health, further affecting vitamin D absorption and metabolism.
- Women using vitamin D supplements should consider the potential interaction with estrogen-based contraceptives, which may alter vitamin D metabolism and its binding proteins.
- Given the connection between contraception and vitamin D levels, it's essential for women planning to conceive to ensure they have adequate vitamin D levels before discontinuing estrogen-based contraceptives, as they may be at risk of deficiency.
- The study revealed that cultural factors, such as sunlight exposure and diet, can contribute to nutritional deficiencies like vitamin D deficiencies in different populations, such as African-American women.
- Health-and-wellness awareness programs should prioritize addressing women’s vitamins, multi-vitamins, and specifically vitamin D deficiencies, as they can impact women's health and the health of their babies.
- Nutrition science should focus on understanding the complex relationship between contraceptives and vitamins, particularly vitamin D, to ensure optimal health for women during different stages of their lives.
- To maintain good health and prevent potential deficiencies, women should engage in regular outdoor activities, consume foods rich in vitamins, and consider supplements, especially when using estrogen-based contraceptives, to ensure their vitamin D levels remain adequate.
