Pill B vitamin depletion and nutrition: what to know

Q: Does taking the combined pill definitely mean your B vitamins will be low?

Not on its own. Research links pill use with lower levels of B6, B12, and folate. Your diet, the specific pill you take, and how long you have taken it all play a part. If you are concerned, your GP can arrange a blood test to check your actual levels.

Q: Is low B6 on the pill linked to mood changes?

B6 helps your body make neurotransmitters, including serotonin, and some research links lower B6 in pill users with mood-related changes. Mood has many drivers, so this is not a clear-cut link. If your mood has felt consistently harder to manage since starting the pill, it is worth raising with your GP rather than putting it down to nutrient levels alone.

Q: Should you take a folic acid supplement while on the pill?

There is no blanket UK recommendation to take folic acid just because you are on the pill. If you plan to conceive after stopping, UK guidance recommends 400 micrograms of folic acid daily, starting at least one month before conception. Speak to your GP well before stopping the pill if pregnancy is in your plans.

Q: Which foods are most useful to focus on for B12 if you eat plant-based and are on the pill?

Vitamin B12 is found almost entirely in animal products. If you eat plant-based, fortified foods like plant milks and some breakfast cereals are your most accessible sources. Since pill use is linked with lower B12 levels, it is worth talking through your intake or possible supplementation with a registered dietitian.

A tired stressed pregnant woman resting at home.

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The low-level tiredness, the flatness that sits with you through the day, the mood that feels harder to manage than usual. These are experiences that can have more than one cause. If you take a combined oral contraceptive (COC), it is worth understanding how the pill can deplete some of your B vitamins and other nutrients. Research links COC use with lower levels of several key nutrients, including B vitamins. Your nutritional picture is worth paying attention to.

What the evidence tells us about the pill and nutrient levels

If you have been on the pill for a while and feel a bit depleted, your nutrient levels may be part of the picture. Studies link combined oral contraceptives with lower levels of riboflavin (B2), vitamin B6, vitamin B12, and folate. The reasons are still being worked out, though the pattern shows up consistently enough across studies to be worth knowing about.²

Vitamin B6 seems to be affected most. One study found that many pill users who were not taking supplements had lower B6 markers. That is a single finding, and it does not apply to everyone on the pill, though it points to something worth considering. Vitamin B6 supports the production of brain chemicals involved in mood, including serotonin. A small amount of research has explored whether it could help with mood changes on the combined pill, but the evidence is still limited. Mood has many drivers. If low mood is something you are noticing, it is a thread worth raising with your GP.³

For vitamin B12 and folate, studies show lower blood levels in pill users than in non-users. Folate matters especially if pregnancy is on your mind at any point, because having enough folate around conception lowers the risk of neural tube defects, which affect how a baby's spine and brain develop. If you are thinking about stopping the pill to try for a baby, it is worth speaking to your GP well ahead of time. General nutrition information does not replace advice for your own situation here.¹

Food sources worth prioritising

A varied, balanced diet is still the main way to support your nutrient levels. The foods below cover the nutrients most often linked with lower levels in pill users.

Folate: dark leafy greens (spinach, kale, spring greens), legumes (lentils, chickpeas, kidney beans), broccoli, and fortified breakfast cereals.
Vitamin B6: fish (salmon, tuna), chicken, chickpeas, potatoes, and bananas.
Vitamin B12: found almost entirely in animal products, so meat, fish, eggs, dairy, and fortified plant milks or cereals if you eat plant-based.⁴

Chicken and vegetable burrito on a white plate with garnishes.

These foods also fit comfortably within general healthy eating, plenty of vegetables, a range of protein sources, and wholegrains. Eating a wide variety of them, rather than leaning heavily on any single food, gives you the broadest nutritional base.

Is supplementation is worth taking?

There is currently no blanket UK recommendation that everyone on the pill should take B vitamin supplements. The decision is an individual one. Things like your diet, how long you have been on the pill, and whether you have symptoms that might relate to nutrient levels all matter.⁵

If you are thinking about supplements, speak to your GP, pharmacist, or a registered dietitian before you start. They can look at your situation and, where it makes sense, arrange a blood test to check your actual levels rather than supplementing on the basis of risk alone. This article does not recommend specific supplements, brands, or doses.

Frequently Asked Questions

Does taking the combined pill definitely mean your B vitamins will be low?

Is low B6 on the pill linked to mood changes?

Should you take a folic acid supplement while on the pill?

Which foods are most useful to focus on for B12 if you eat plant-based and are on the pill?

Sources

[1] Oral contraceptives: effect of folate and vitamin B12 metabolism

For vitamin B12 and folate, studies show lower blood levels in pill users than in non-users
[2] Oral contraceptives and changes in nutritional requirements.

Combined oral contraceptive use is associated with lower levels of several key nutrients, including B vitamins (specifically B2, B6, B12, and folate) and the mineral magnesium.
[3] Oral contraceptive use: impact on folate, vitamin B6, and vitamin B12 status

One study found that a large proportion of pill users without supplementation showed reduced B6 biomarkers.
[4] Oral Contraceptive Pill: Common nutritional deficiencies & how to fix them with REAL food

A varied and balanced diet is the primary approach, prioritising foods rich in folate (dark leafy greens, legumes), vitamin B6 (fish, chicken, chickpeas), vitamin B12 (animal products), and magnesium (nuts, seeds, leafy greens).
[5] A Review on Oral Contraceptives: The Nutritional Implications

There is currently no universal UK recommendation from an official body that all COC users should take B vitamin supplements, and supplementation decisions should be individualised and discussed with a healthcare provider.