If you’ve opted for the contraceptive pill as your chosen form of birth control, you’ve probably heard about some of the more common side effects, including headaches, mood swings and nausea. However, there’s some suggestion that there might be another, lesser discussed issue that may well have a profound impact on your wellbeing – and it’s all to do with the way in which we absorb and use nutrients.

Some studies suggest that oral contraceptives can alter the body’s ability to metabolise key vitamins and minerals such as folate, vitamins B6 and B12. So, does that mean we should be taking supplements if we’re using oral contraceptives? The answer is a little more nuanced than you might think.  

“Hormonal changes [such as taking the pill] generally affect how the body absorbs nutrients,” explains Dr Shazia Malik, a consultant obstetrician and gynaecologist at The Portland Hospital. “One of the lesser-known side effects of the pill is its ability to cause deficiencies in various vitamins and nutrients. The key nutrients that are depleted by taking the pill are vitamins B6, B12 and folate, with some research showing that the minerals magnesium, zinc and selenium are also affected.”

However, as Miss Ghada Salman, a consultant gynaecologist at hospitals including The London Clinic, reveals, it’s worth noting that some of the earlier studies carried out on women taking oral contraceptives were based on those who had received higher doses than would normally be prescribed today.  

“Previous research has shown that oral contraceptives can interfere with absorption and the metabolism of certain vitamins, such as folate and B12, because the hormones in contraceptives in them can impact certain enzymes in the liver,” explains Miss Salman. “However, we can’t assume that everyone who is on the pill will have a vitamin or mineral deficiency. It’s a very complex chemistry that happens in the body, and let’s not forget that every person’s level of vitamin and mineral storage varies depending on diet, lifestyle and genetics.”

What causes nutritional deficiencies isn’t always clear, but it’s good to be aware of the influence that the pill can have on your body’s nutrient stores – particularly if you follow a vegetarian or plant-based diet, which might make it slightly harder to get a lot of certain key micronutrients, such as B12.

“We need to look at the whole picture before we can confidently say that any nutritional deficiency is caused directly by oral contraceptives,” says Miss Salman. “However, for those people who aren’t managing to get all those necessary vitamins and minerals from their diet and are also taking oral contraceptives, it could be a good idea to take a multivitamin supplement.”

But what about those women who are coming off the pill with the intention of starting a family or thinking about fertility? Do we need to be worried about folate levels, for example, after years of oral contraceptive use? The short answer is no. At the moment, no current research has found that pill-related folate depletion affects the chances of conception.

“While there is evidence to suggest that taking the oral contraceptive pill lowers the levels of folate (also known as vitamin B9) in the blood, there is no evidence that this has a clinical effect and it does not affect future fertility or chances of conception,” says Dr Mel Davis-Hall, a GP, women’s health specialist and medical director of contraceptive review platform The Lowdown.  

Unless stated otherwise by your GP, most supplements are safe to take with oral contraceptives. However, as with any supplement, you need to make sure that you’re getting the right dosage. You can check the recommended RDA by looking at the NHS website or by speaking with your GP.

“As long as you’re not taking excessive amounts of any supplement, it should be safe to take alongside your oral contraceptives,” adds Miss Salman. “But if in doubt, do consult a medical professional.” 

While most supplements and multivitamins don’t generally affect the efficacy of contraceptives, there are some supplements – such as herbal remedies – that GPs recommend against taking alongside certain contraceptives.

“Some natural remedies can cause oestrogen and progesterone to drop to levels that are lower than normal, in turn speeding up the coprocessing of contraceptive hormones and making the contraceptive less effective,” says Dr Malik. “One example of an enzyme inducer is St John’s wort, which is generally used to treat depression or sleep problems.” 

“Although taking the pill does not guarantee nutrient deficiencies, it is still important to discuss the risks with your GP or healthcare provider, particularly if you are classed as having a higher risk of nutritional deficiencies with one of the factors below,” says Dr Malik.

• Malabsorption in the gut
• Rapid excretion of vitamins
• Inadequate intake of vitamins and minerals in the diet
• Increased nutrient demand (from medical history/other medications) 

Speaking on the studies referenced above, dietitian Ro Huntriss says: “Such findings make it even more important for people to aim for a healthy, well-balanced and nutritionally complete diet containing all essential vitamins and minerals.

“If your diet lacks certain food groups or you feel there may be some nutrient gaps, consider taking a nutritional supplement.”

Vitamin and mineral deficiencies can hard to be spot on your own, but if you’re feeling out of sorts, then track your symptoms and speak to your GP to determine whether a vitamin deficiency could be the culprit.  

Vitamins B, C, D

“If you are prone to catching colds or bugs, then this may be a sign that your immune system may not be working to its full capacity,” says Huntriss. “An adequate intake of certain nutrients such as vitamin D, vitamin C, folate, zinc and iron, among others, are essential for supporting the immune system and allowing it to work to its full capacity. 

Vitamins A, B12 and iron

“A lack of iron, folate and vitamins B12 and A can lead to anaemia, symptoms of which include fatigue, shortness of breath and dizziness.

Selenium

 Other things to keep an eye on are the health of our hair and nails. Hair loss could be a sign of low levels of selenium, while weak or brittle nails could be a sign of low levels of zinc. The best way to know if your levels of these nutrients are optimal is to measure them via a blood test. ”

According to the experts, the bottom line is that oral contraceptives are safe for most women, but it’s worth knowing that they can aggravate existing nutritional deficiencies, especially if you’re not eating a well-rounded diet or omitting certain micro-nutrient-rich foods, such as leafy green vegetables, fruit, animal protein and dairy. Supplementing your diet can be a great way of supporting your body, so it’s worth considering whether you could benefit from one and consult a medical professional or dietitian if in doubt.  

Images: Getty