You take a tablet every day to manage your blood pressure, your reflux or your blood sugar. It does its job. What the leaflet rarely mentions is that some of these medicines, taken for months or years, can slowly drain specific nutrients from your body.
This is not a reason to stop anything. The medicines are doing important work. But the nutrient side of the equation is real, it tends to build up quietly, and it gets more relevant after 40 when your reserves are already thinner.
Here is which common medications are linked to which nutrient shortfalls, what the symptoms can look like, and the sensible steps to take. None of this replaces a conversation with your GP or pharmacist.
Why this happens
Medicines and nutrients share the same body. A drug that changes your stomach acid, your kidney function or how your gut absorbs things will often affect nutrients as a side effect of doing its main job.
There are three broad mechanisms:
- Reduced absorption. Some drugs change the gut environment so a nutrient is taken up less efficiently.
- Increased loss. Others make your kidneys excrete more of a mineral in urine.
- Altered metabolism. A few interfere with how a nutrient is activated or used.
The effect is usually gradual. A few weeks rarely matters. Years of daily use is where a shortfall can quietly develop, which is why long-term medication after 40 is the situation to watch.
The main culprits
The table below summarises the best-documented drug and nutrient links. The detail follows underneath.
| Medication | Commonly used for | Nutrient(s) it may deplete |
|---|---|---|
| Proton pump inhibitors (omeprazole, lansoprazole) | Acid reflux, heartburn | Magnesium, vitamin B12 |
| Metformin | Type 2 diabetes | Vitamin B12 (and possibly magnesium) |
| Diuretics (water tablets) | Blood pressure, heart failure | Magnesium, potassium |
| Statins | High cholesterol | Coenzyme Q10 (CoQ10) |
| Corticosteroids (long-term) | Inflammation, autoimmune conditions | Calcium, vitamin D |
| Combined contraceptive pill | Contraception | B vitamins, magnesium, zinc |
Acid reflux medicines (PPIs) and magnesium
Proton pump inhibitors like omeprazole and lansoprazole are among the most prescribed drugs in the UK. By lowering stomach acid, they ease reflux, but acid also helps you absorb certain minerals.
Long-term use is linked to lower magnesium levels, enough that in 2011 the US drug regulator issued a formal safety warning on the association. Reduced acid can also lower vitamin B12 absorption over years of use.
If you have been on a PPI for a long stretch, magnesium and B12 are reasonable things to ask your GP about. We cover the wider picture in our guide to what depletes magnesium.
Metformin and vitamin B12
Metformin is the first-line medicine for type 2 diabetes and a genuinely valuable one. It also has a well-established link with lower vitamin B12 over time.
A long-term analysis of the Diabetes Prevention Program (Aroda and colleagues, 2016) found that extended metformin use raised the risk of B12 deficiency. Because low B12 causes fatigue, brain fog and nerve symptoms that overlap with other conditions, it is easy to miss.
Most diabetes teams now consider periodic B12 checks for long-term metformin users. A simple blood test settles it.
Diuretics, magnesium and potassium
Many blood pressure “water tablets” work by making your kidneys excrete more fluid and sodium. The same process increases the loss of magnesium and potassium in urine.
These two minerals are closely linked, and a shortfall in both can show up as cramps, fatigue and palpitations. We explain why they travel together in our guide to magnesium and potassium.
Potassium is something your GP should manage and monitor, not something to supplement yourself. Magnesium is the one most people can safely top up within label doses.
Statins and CoQ10
Statins lower cholesterol by blocking an enzyme pathway in the liver. That same pathway also produces coenzyme Q10, a compound your cells use to make energy, so statins can lower CoQ10 levels.
Whether this explains the muscle aches some people report on statins is still debated, and the evidence on CoQ10 supplements helping is mixed. It is worth knowing about, but not a reason to stop a statin. Raise any muscle symptoms with your GP.
Long-term steroids, calcium and vitamin D
Corticosteroids taken for months, for conditions like asthma, arthritis or autoimmune disease, reduce calcium absorption and alter vitamin D metabolism. Over time this affects bone health.
Anyone on long-term steroids should already be having bone health monitored, and vitamin D with calcium is often part of that plan. Our guide on improving vitamin D absorption covers how to get the most from a supplement.
The contraceptive pill and B vitamins
The combined pill is linked to lower levels of several nutrients, including some B vitamins, magnesium and zinc. The effects are usually modest, but they can matter for women on the pill for many years, or those whose diet is already tight.
A varied diet covers most of this. A standard multivitamin or targeted top-up can help where it does not.
What to actually do
The aim is awareness, not alarm. A few sensible steps cover most situations.
- Don’t stop your medication. The benefit almost always outweighs the nutrient cost, and stopping can be risky. This is about managing the side, not abandoning the medicine.
- Know your list. If you take any of the medicines above long term, note which nutrients are linked.
- Ask for the right blood test. B12 for metformin or long-term PPI use, magnesium and potassium for diuretics. Tests remove the guesswork.
- Eat to cover the gaps. A diet rich in vegetables, pulses, nuts, seeds and lean protein supplies most of these nutrients.
- Supplement sensibly where needed. A well-absorbed magnesium such as magnesium glycinate, or a vitamin D3 and K2 supplement, can fill specific shortfalls. Always check with your GP or pharmacist first, since some supplements interact with medicines.
The single most useful move is simply telling your pharmacist which supplements you are considering. They can check for interactions in minutes.
FAQ
Which medications deplete magnesium?
Proton pump inhibitors for acid reflux and diuretics for blood pressure are the most documented. Long-term PPI use is linked to lower magnesium, and diuretics increase magnesium loss through urine. The combined contraceptive pill is also associated with modestly lower levels.
Does metformin cause vitamin B12 deficiency?
Long-term metformin use is linked to a higher risk of low vitamin B12. The effect builds over years, and low B12 can cause fatigue, brain fog and nerve symptoms. Many diabetes teams now check B12 periodically. A blood test confirms whether you need to act.
Should I stop my medication if it depletes nutrients?
No. The benefit of the medication almost always outweighs the nutrient cost, and stopping can be dangerous. The right approach is to monitor the relevant nutrient, eat to cover the gap, and supplement sensibly with your GP or pharmacist’s input.
Do statins really lower CoQ10?
Statins can lower coenzyme Q10 because they block the same liver pathway that produces it. Whether this explains the muscle aches some people experience, and whether CoQ10 supplements help, is still debated. Discuss any muscle symptoms with your GP rather than stopping the statin.
How do I know if a medication is affecting my nutrient levels?
The clearest way is a blood test for the specific nutrient linked to your medication, arranged through your GP. Symptoms like fatigue, cramps, brain fog or palpitations can be clues, but they overlap with many causes, so testing is more reliable than guessing.
This article is for general information and is not medical advice. Never stop or change a prescribed medication without speaking to your GP. Food supplements are not a substitute for a varied, balanced diet, and some interact with medicines, so check with your GP or pharmacist before starting one.
References
- Mohn ES, et al. Evidence of drug-nutrient interactions with chronic use of commonly prescribed medications. Pharmaceutics. 2018. link
- Aroda VR, et al. Long-term metformin use and vitamin B12 deficiency in the Diabetes Prevention Program Outcomes Study. Journal of Clinical Endocrinology & Metabolism. 2016. link
- US Food and Drug Administration. Drug safety communication: low magnesium levels can be associated with long-term use of proton pump inhibitor drugs. 2011. link
- Palmery M, et al. Oral contraceptives and changes in nutritional requirements. European Review for Medical and Pharmacological Sciences. 2013. link
