We all know that eating a healthy and balanced diet, exercising regularly, and getting plenty of sleep is important for health. However, eating your greens and taking the occasional supplement may not be enough to reach optimum health when you’re taking a contraceptive pill.
Research into the contraceptive pill and nutrition first started in the 1970’s with the results suggesting that taking the pill can impact the levels of some B-vitamins, vitamin C, vitamin E, as well as the minerals Zinc, Selenium and Magnesium. We’ve looked at the research and filtered out the scientific jargon to highlight key micronutrients to be extra aware of when taking oral contraception.
What is contraception?
Contraception describes the methods or devices used to prevent pregnancy. It’s been used for centuries, but it wasn’t until the 20th century that safe and effective methods were introduced to society. The oral contraceptive pill was fist introduced in the UK in the early 1960’s and was made available to married women through the NHS. In 1967 the NHS Family Planning Act 1967 was passed, which recognised that unwanted children in low-income households caused a serious financial strain for those families, opening up the availability of the contraceptive pill to women in the UK.
How do oral contraceptive pills work?
There are 2 main categories of pills available in the UK through the NHS, the combined pill and the progesterone-only pill. Both pills introduce additional hormones into the body, disrupting the natural levels that are present throughout the monthly cycle and preventing pregnancy. The combined pill contains both progesterone and oestrogen and works by preventing the ovaries from releasing an egg each month. The progesterone-only pill thickens the mucous in the cervix to stop sperm from reaching an egg. Both are 99% effective in preventing pregnancy.
Does taking the pill change your nutritional requirements?
One of the lesser known and researched side effects of oral contraception is its effect on vitamin metabolism. The WHO first emphasised the clinical relevance of nutrient requirements when taking oral contraception in 1975[1]. But to this day, it is something that remains mostly unknown and rarely talked about, despite it being one of the most widely used medications by women all over the world.
Folic Acid
Folic Acid is a water-soluble B vitamin found naturally in foods such as dark leafy vegetables, fruits, beans, eggs, dairy and grains. You can also find it in food supplements and fortified foods. A lack of dietary folic acid leads folate deficiency, following essential processes:
- Cell division
- Amino acid synthesis
- Blood formation
- Psychological function
- Immune function
The use of oral contraception may negatively impact folate status in the body. An initial study found that women who were taking the pill had lower levels of folate, and it was assumed that the pill was preventing efficient absorption or altering the metabolism of folate in the body.[2] A review of available studies suggests folic acid supplementation in women using oral contraceptives is worth considering.[3]
Vitamin B2
Vitamin B2 (Riboflavin), is another water-soluble vitamin found in a variety of widely consumed foods, such as vegetables and meat. It’s best known for it’s role in energy and metabolism, but is also involved in:
- The nervous system
- Red blood cell maintenance
- The function of the skin
- Eye health and vision
- Protecting cells from oxidative stress
Because vitamin B2 is water soluble, it passes through the body quicky, meaning it’s easy to become deficient when dietary intakes are lower than the intake amount needed. Studies investigating the impact of contraception on vitamin B2 started in the 70’s, and published findings suggesting that the pill was negatively impacting the levels of vitamin B2 in women who were taking it. Interestingly, studies found that taking a supplement improved pre-existing vitamin B2 deficiencies.3
Vitamin B6
Vitamin B6 is also a member of the water-soluble B-vitamins and is used by the body to produce vitamin B6 coenzymes and facilitate 100’s of reactions, including:
- Energy metabolism
- Red blood cell formation
- Protein metabolism
- Hormonal activity regulation
A large population study in the United States found that 75% of women taking oral contraception, without the use of a dietary supplements, had reduced levels of vitamin B6 biomarkers.[4] Looking at all the available evidence, supporting the diet with additional B6 may prove to be beneficial in women taking the pill.3
Vitamin B12
Vitamin B12 is well known by vegans and vegetarians as the missing micronutrient in a plant-based diet. However, it may well be something to consider supplementing with when taking the pill3. Vitamin B12 is mainly found in animal-based foods, and, like other B-vitamins, is involved in energy yielding processes, as well as:
- The functioning of the nervous system
- Homocysteine metabolism
- Psychological function
- Cell division
Similarly, to the other B-vitamins we’ve highlighted, B12 levels in women using oral contraception was lower than in non-users3.
Vitamin C
Vitamin C is a well-known nutrient, mostly known as the immune vitamin. It’s widely available in the diet in fruit and vegetables and is important for full-body health and wellbeing by:
- Supporting collagen formation in the skin, gums, blood vessels and joints
- Contributing to the function of the nervous system
- Protecting cells from oxidative stress
- Increasing iron absorption
Initial studies looking at the interaction between vitamin C and oral contraception looked at immune biomarkers and found that these tended to be lower in women who were taking oestrogen pills. However, it was also found that healthy intakes of vitamin C prevented the risk of deficiency in this micronutrient.3
Vitamin E
Well known for its antioxidant capabilities, vitamin E is another micronutrient impacted by taking the pill. Some researchers believe that the adverse cardiovascular effects of the pill may be down to a change in vitamin E status in women who take the pill.3
Zinc
It turns out that it’s not just vitamins that are impacted by the pill, but essential minerals too, with Zinc being one of them. Zinc is involved in a whole host of important functions in the body, including:
- DNA and protein synthesis
- Macronutrient metabolism
- Brain health and cognitive function
- Bone health
- Skin, hair and nail heath
Several studies are aligned in suggesting that women taking oral contraception have lower levels of circulating zinc in their bodies. This may be due to changes in absorption when taking the pill.3
Selenium
Selenium is another important mineral found in the diet, mostly in whole grains and animal products, and is best known for its role in maintaining thyroid function. It’s also required by:
- The immune system
- Hair and nails
- Antioxidant enzymes
Multiple studies suggest that the pill can interfere with selenium absorption, putting women who take it at risk of deficiency.
Magnesium
Last but not least is magnesium, a mineral involved in processes ranging from electrolyte balance to psychological function. It’s important to get enough magnesium in the diet to support:
- Bone and teeth health
- Neurological function
- Muscle function and heart health
- Protein synthesis
- Energy-yielding metabolism
When the body is deficient in magnesium, it changes the ratio of magnesium to calcium, which can affect blood coagulability.[5] This increases the risk of blood clots accumulating in blood vessels. Several studies are aligned in finding that serum magnesium in women who take oral contraception is lower than women who don’t, suggesting a need for higher intakes of magnesium when taking to contraceptive pill.3
Possible reasons why the pill may cause nutrient deficiencies.
To say that drug interactions in the body are complex would be an understatement, which means it can be hard to pinpoint exactly why taking the pill can cause nutrient deficiencies. Possible reasons include reduced liver function, as taking oral contraceptive is associated with liver complications.[6] Because the liver processes absorbed nutrients, changes in its function could mean that nutrients are inefficiently processed or eliminated from the blood stream.
Another possible reason can be reduced absorption in the gut due to increased inflammation. Some studies report that taking oral contraception can cause intestinal inflammation, which can alter the digestive process and limit how much nutrition absorbed in the gut.[7]
How to obtain plenty of vitamins and minerals while on birth control
Eating a balanced diet, with a variety of fruits, vegetables, nuts and seeds, as well as some animal products is the key to providing your body with the nutrition it needs to function at its best when taking the pill. These foods are especially beneficial to include when taking the pill to lower the risk of becoming deficient in the following nutrients:
- Folate: leafy greens, beans
- Vitamin B2: dairy, eggs
- Vitamin B6: fish, chicken, fruits, vegetables
- Vitamin B12: animal proteins (fish, poultry, red meat, dairy)
- Vitamin C: fruits, vegetables
- Vitamin E: nuts, seeds, oils from both sources
- Magnesium: nuts, seeds, greens
- Selenium: Brazil nuts, seafood, poultry
- Zinc: oysters, red meat, poultry, beans, nuts
You can also take supplements for extra support.
[1] http://libdoc.who.int/trs/WHO_TRS_575.pdf
[2] Shojania AM, Hornady G, Barnes PH. Oral contraceptives and serum-folate level. Lancet. 1968 Jun 22;1(7556):1376-7. doi: 10.1016/s0140-6736(68)92081-3. PMID: 4172676.
[3] https://www.europeanreview.org/wp/wp-content/uploads/1804-1813.pdf
[4] MORRIS MS, PICCIANO MF, JACQUES PF, SELHUB J. Plasma pyridoxal 5'-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003-2004. Am J Clin Nutr 2008; 87: 1446-1454.
[5] DiNicolantonio JJ, O'Keefe JH. Magnesium and Vitamin D Deficiency as a Potential Cause of Immune Dysfunction, Cytokine Storm and Disseminated Intravascular Coagulation in covid-19 patients. Mo Med. 2021 Jan-Feb;118(1):68-73. PMID: 33551489; PMCID: PMC7861592.
[6] LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. Estrogens and Oral Contraceptives. [Updated 2020 May 28]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK548539/
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4752384/