Who knew that estrogen-containing contraception pills could increase vitamin D in women? Well, US based researchers from the National Institute of Environmental Health Sciences, North Carolina, have recently found out that African-American women who consumed estrogen-rich contraceptive pills had 20% increased amounts of a major biomarker of vitamin D — 25(OH)D — in their blood.

Researchers investigated the association between the use of hormonal contraception and vitamin D in women status in a cohort study containing a total of 1,662 African-American women aged 23-34. All of the women gave blood samples that were tested for 25[OH] D levels at the beginning of the study. Questionnaires determining the use of contraception, vitamin supplements, and food frequency questionnaires to assess dietary vitamin D were also filled by the participants.

The findings after adjusting for other contributory sources of vitamin D in women such as seasonal exposure to sunlight showed that the use of contraceptive pills, patch or ring containing estrogen was associated with a 20% higher level of 25-hydroxy vitamin D. The study was published recently in the Journal of Clinical Endocrinology & Metabolism.

The lead author of the study, Quaker Harmon, of the National Institute of Environmental Health Sciences, North Carolina, USA, made it clear that women experienced the boost of vitamin D due to estrogen in their method of contraception by saying, “Our findings suggest that contraceptives containing estrogen tend to boost vitamin D levels, and those levels are likely to fall when women cease using contraception.”

The researchers believe that their study has the potential for counseling women who are planning to conceive and for identifying those who may be at a risk of vitamin D deficiency. It was suggested by the lead author that women planning on ceasing the use of birth control should get their vitamin D levels checked to avoid any vitamin D related deficiency at the time of conception and during pregnancy.

A few weeks earlier, Public Health England (PHE) recommended that all people over the age 1 should take a daily supplement containing 10 micrograms (mcg) of vitamin D, especially during the autumn and winter time. There is also special recommendation of taking a supplement all year round for people from ethnic groups with dark skin, according to the BMJ.

Another study published in the American Journal of Clinical Nutrition directs towards the fact that African-American women suffer from hypovitaminosis D more than the white women. It was highlighted that a very small portion of American African population takes a nutritional supplement to counter the vitamin D deficiency and those who do take such supplements (200 IU/d) are unable to maintain their vitamin D levels up to the normal mark. These facts leave room for developing adequate measures to ensure the adequate vitamin D in women.

Similarly, scientific evidence from the Journal of Nutrition pinpoints the fact that vitamin D deficiency is prevalent in North America. Despite the fact that most of the foods such as milk are fortified with vitamin D, the presence of severe form of vitamin D deficiency, osteomalacia, is still observed.

The reason for vitamin D deficiency in African American has been discussed in another study in the Journal of Nutrition. It says that the Africans Americans do not achieve optimal 25-hydroxyvitamin D [25(OH)D] concentrations at any time of the year due to higher pigmentation that reduces vitamin D production in the skin.

Moreover, it has also been observed that median intakes of vitamin D in women of African American origin are below the recommended intakes as compared to other ethnic groups, whether with or without the inclusion of vitamin D from supplements.

Furthermore, the scientific evidences suggest that women who have a serum 25(OH)D level of <20–25 nmol/L (8–10 μg/L) are at a higher risk of rickets or osteomalacia and their nutritional supplementation of vitamin D should be monitored keenly to avoid bone related problems, especially in the pregnant women or those who are planning for it.