Dr. Sarah Penney, ND, MSc
Are You Taking Birth Control? See What Nutrients You Could Be Missing!
The birth control pill is arguably one of the most popular medications used among certain age groups, and has recently celebrated it's 50th birthday. Throughout it's successful career, oral contraceptives have changed their form, formulation, dosages, routes of administration, and have come to rest in a position where they offer different options to suit almost every woman. Despite their popularity, there is lots of controversy about the use of synthetic contraceptives in the natural health community, one critique centring around nutrient depletion arising from its administration. Even if you are using a nuva-ring or receiving an injectable form of progesterone, your body still has to absorb, detoxify and process those hormones which could over time affect the levels of certain vitamins and minerals in your body. Although this is not exactly a hot topic of research, let's take a look at what the studies show about contraceptive medications and nutrient depletion.
The debate on this topic started shortly after the oral contraceptive pill was born and changed
the face of conception forever back in the early 60s. Soon after the pills hit the market, two
studies were released showing that women taking oral contraceptives had lower levels of folate
and B6 than women who did not (1,2). This finding was especially concerning because folate
(taken in supplement form as folic acid) is important for proper development of a baby and
helps to protect against certain birth defects. You might be thinking to yourself - but women
on the birth control pill cant get pregnant! Although oral contraceptives are very effective in
preventing pregnancy, they are not a guarantee and any slip up in taking the pill or interaction
with medications like antibiotics can lead to an accidental pregnancy in women who are sexually active. Furthermore, many women who stop taking oral contraceptives do so to try and get pregnant, but if their levels of folate are low this could also lead to an increased risk of birth
defects. At the time of a review published in 1980, up to 200 million women were using oral
contraceptive agents world wide. Authors examined the evidence and concluded that the levels
of 6 different nutrients were lower in women taking oral contraceptives, including B2, B6, folate,
B12, vitamin C and zinc. (3) Investigation into this issue continued, and a study published in
1998 reported that although B12 levels were lowered in women on oral contraceptive, folate
status seemed to be intact. (4) This effect on B12 has since been debated through conflicting
clinical results in further studies, and a concrete conclusion about the effect on folate status has
yet to be reached (5,6).
There are several concerns regarding the application of these studies in current medical
practice. First of all, the formulation of oral contraceptives that are currently available is different than in the past - there has been an important transition over time to products with lower doses of hormone, and the medications being taken during the majority of the studies discussed were of a much higher concentration. The other issue is that many (although not all) of the studies just looked at groups of women on oral contraceptives, and did not take measurements from comparable participants who were not taking any oral contraceptives. Although investigations are still ongoing, one important deficiency that has persisted throughout the evidence is B6. (6) This nutrient, also known as pyridoxine, is important in many metabolic pathways in the body. One reason that B6 may be low in women taking long-term doses of oral contraceptives is that this nutrient plays a key role in estrogen detoxification pathways, and women who are taking extra hormones in the form of contraceptives may be putting these pathways are under a significant amount of strain to metabolize and detoxify these compounds. Unfortunately no research is available examining the effect of contraceptives that only contain progestin (the synthetic form of progesterone), often referred to as the minipill or administered as a shot. I commonly associate certain signs I see in women on oral contraceptives in my naturopathic practice with a deficiency of certain B vitamins including low energy, sluggish metabolism and even cravings.
Although research is still ongoing regarding the issue of nutrient depletion in women on oral
contraceptives, I think there is enough evidence to suggest that attention should be payed
to the status and intake of B vitamins. This can especially be a concern for women who are
at increased risk for B12 deficiency like vegans and vegetarians. Adequate intake can be
analyzed through dietary counselling - ensuring the intake of B12 through foods like certain
dairy products, fish and seafood, eggs, or possibly supplementation if the patient is not
consuming any of these food groups. A patient's B12 status can be very easily evaluated
through a routine blood test, and monitored over time for change. Deficiency of B6 on the other
hand can be harder to detect, but is found in a wide range of foods including most beans,
fruits and vegetables like potatoes, carrots, bananas, and a variety of meats. Supplementation
should again be considered on an individual basis and I find it can be beneficial if clinical signs
and symptoms of mild deficiency are present, especially in individuals who are using oral
- Dr. Sarah Penney, ND, MSc
1. Prasad, A.S. et al. Effect of oral contraceptive agents on nutrients: II. Vitamins. Am J Clin
Nutr. 1975; 28(4): 385-91.
2. Prasad, A.S. et al. Effect of oral contraceptives on nutrients. III. Vitamins B6, B12, and folic
acid. Am J Obstet Gynecol. 1976; 125(8): 1063-9
3. Webb, J.L. Nutritional effects of oral contraceptive use: a review. J Reprod Med. 1980:
4. Green, T.J. et al. Oral contraceptives did not affect biochemical folate indexes and
homocysteine concentrations in adolescent females. J Am Diet Assoc. 1998:98(1); 49-55.
5. McArthur J.O. et al. Biological variability and impact of oral contraceptives on vitamins B(6),
B(12) and folate status in women of reproductive age. Nutrients. 2013 Sep 16;5(9):3634-45.
6. Wilson S.M. et al. Oral contraceptive use: impact on folate, vitamin B6, and vitamin B12
status. Nutr Rev. 2011 Oct;69(10):572-83.