PPIs, calcium absorption and osteoporosis
- Jul 8
- 7 min read
Long-term PPI use has been linked to a higher fracture risk, prompting a common question: do these medicines affect calcium absorption and bone density?
Here's what the evidence shows, and how to make sense of it with your GP.
In Brief
Some studies have linked long-term PPI use to a modest increase in fracture risk, but the effect on bone health is smaller and more conditional. For most people taking a PPI, the practical steps are straightforward.
This article explains:
What are PPIs?
PPIs reduce stomach acid by blocking the enzyme that produces it. They are effective for a range of digestive conditions and are among the most widely prescribed medicines in the UK. Common examples include omeprazole, lansoprazole, esomeprazole, and pantoprazole.
Why has bone health become a concern?
Several large observational studies have found an association between long-term PPI use and increased fracture risk, particularly hip and spine fractures. This association led researchers and clinicians to ask whether reducing stomach acid might affect how the body absorbs calcium.
Association is the important word here. Observational studies identify patterns; they do not establish that the medication itself caused the fractures. People prescribed PPIs long-term tend to be older, to have multiple health conditions, and to be taking other medications. All of these independently raise fracture risk. Separating the effect of the drug from the characteristics of the person taking it is difficult, and few studies have been able to do this fully.
Stomach acid, calcium, and what the research shows
How acid relates to calcium absorption
Calcium needs to dissolve before it can be absorbed. Stomach acid helps dissolve certain forms of calcium, so reducing acid could theoretically lower absorption of some calcium sources.
How much this affects absorption depends on the form of calcium involved.
Calcium carbonate, the most common form in supplements, needs stomach acid to dissolve. In a New England Journal of Medicine study, people with normal stomach acid and people with achlorhydria (an absence of stomach acid) absorbed calcium citrate equally well, but calcium carbonate absorption dropped sharply in those with achlorhydria. Taking calcium carbonate with food largely restored its absorption. Our article on choosing a calcium supplement for osteoporosis explains the difference between calcium carbonate and calcium citrate in detail; citrate absorbs independently of acid and is generally better suited to people taking PPIs.
Calcium absorption from food behaves differently. Absorption from dairy products, fortified foods, calcium-set tofu, and calcium eaten as part of a mixed meal appears substantially less affected by low stomach acid than absorption from calcium carbonate supplements taken alone.
What the absorption studies show
Studies examining how PPIs affect calcium absorption are inconsistent. Some show a small reduction in fractional calcium absorption; others show little or no difference, particularly when calcium comes from food or from acid-independent supplement forms. This is why the form of calcium used has the most bearing on bone health for someone taking a PPI.
What the fracture studies show
A 2016 meta-analysis in Osteoporosis International, pooling 18 observational studies and more than 240,000 fracture cases, found PPI use associated with a modestly higher risk of hip fracture (around 26% higher) and spine fracture (around 58% higher). These relative figures sound large, but the absolute increase in fracture probability for an individual is small, and the studies consistently struggle to separate the medication's effect from the underlying health profile of people who take it long-term.
NICE guidance on assessing fracture risk lists proton pump inhibitors among medicines that may affect fracture risk. It does not classify PPIs among the recognised causes of osteoporosis, but including them on the fracture-risk list is itself a reason to keep bone health monitoring in view for anyone taking one long-term.
Other ways PPIs may influence bone health
Magnesium
Long-term PPI use can, in some cases, contribute to low magnesium levels. Magnesium plays a role in bone mineralisation, in how the body activates and responds to vitamin D, and in muscle function, which is relevant to fall risk. Severe magnesium deficiency from PPI use is uncommon but recognised. The MHRA advises considering a magnesium measurement before starting prolonged PPI treatment and periodically during, particularly for people also taking other medicines that can lower magnesium, such as diuretics.
Vitamin B12
Long-term PPI use may reduce absorption of vitamin B12 in some individuals by limiting the acid needed to release it from food. The evidence on whether this leads to clinically meaningful deficiency is mixed. Low B12 affects nerve function and balance, and this is relevant to falls risk. Falls are a major determinant of fracture, so B12's relevance to bone health runs through this falls pathway rather than a direct effect on bone density itself.
Who may need to pay closer attention
Most people taking a PPI at standard doses for typical indications do not need to make significant changes. Those who may benefit from a conversation with their GP or specialist include people who:
have osteoporosis or osteopenia
have had a fragility fracture
require high-dose PPIs for many years
are over 65
have other established osteoporosis risk factors
take glucocorticoid medications alongside a PPI
In these situations, it is worth raising with a GP or specialist whether ongoing PPI use remains necessary at the current dose, and whether bone health monitoring would be appropriate.
Supporting bone health while taking a PPI
These steps are relevant to bone health generally, and are straightforward to apply regardless of PPI use.
Calcium from food first. Dairy products, tinned sardines or salmon with bones, calcium-set tofu, and fortified plant milks all provide calcium that still requires some stomach acid to absorb, but is far less affected by low acid than calcium carbonate supplements taken alone. Our guide to calcium-rich foods for osteoporosis lists practical sources with amounts.
Vitamin D. Adequate vitamin D is needed for calcium absorption regardless of whether a PPI is involved. Our article on nutrients for calcium absorption covers vitamin D alongside the other co-factors that affect how well calcium is used.
If a supplement is appropriate. For people on PPIs who have been advised to take a calcium supplement, calcium citrate is generally the more suitable choice, because it absorbs without requiring stomach acid. Dose, timing, and whether a supplement is indicated at all are covered in detail in choosing a calcium supplement for osteoporosis.
Exercise. Weight-bearing and resistance exercise supports bone density through mechanical loading, and the evidence for this is well established.
Smoking and alcohol. Smoking is an established risk factor for bone loss. High alcohol intake is associated with reduced bone density and higher fracture risk. Reducing smoking and keeping alcohol within recommended limits both support bone health.
Should you stop taking a PPI because of bone health concerns?
Stopping a PPI is not something to do because of bone health concerns alone. Untreated acid reflux disease, stomach ulcers, or gastrointestinal bleeding carry significant health risks, and any change to PPI use needs to go through the clinician who prescribed it.
If you have concerns about long-term use, the right starting point is a conversation with your prescribing clinician about whether continued treatment at the current dose is still appropriate. Many people are prescribed PPIs long-term without regular review of whether continued use is needed.
Key takeaway
PPIs may reduce absorption of calcium carbonate supplements under some circumstances, and some studies have linked long-term use with a modest increase in fracture risk. The evidence is not conclusive, the effect on most dietary calcium sources appears small, and the absolute fracture risk increase, where it exists, is modest.
If you take a PPI, the most useful approach is to focus on what is known to support bone health: dietary calcium from food, adequate vitamin D, regular exercise, and appropriate medical monitoring where relevant. If you use calcium supplements, the form affects how well it absorbs on a PPI, and it is worth discussing the choice with your GP.
Frequently asked questions
Do PPIs cause osteoporosis?
PPIs have been associated with increased fracture risk in observational studies, but a direct causal link has not been established. People who take PPIs long-term tend to have other characteristics that independently raise fracture risk, which makes it difficult to determine how much of the association is attributable to the medication. Current guidance does not classify PPIs as a primary cause of osteoporosis.
Does omeprazole stop calcium absorption?
Omeprazole, like other PPIs, reduces stomach acid, which is needed to dissolve calcium carbonate. This can reduce how well calcium carbonate supplements absorb when taken without food. The effect on calcium from food, such as dairy, fortified foods, and calcium-set tofu, appears to be much smaller. Calcium citrate supplements, which absorb independently of stomach acid, are generally better suited to people taking PPIs.
Should I take calcium supplements if I am on a PPI?
Whether you need a calcium supplement depends on your dietary intake, not solely on whether you take a PPI. If your calcium intake from food is adequate, a supplement may not be necessary. If a supplement has been recommended and you are taking a PPI, calcium citrate is usually preferred over calcium carbonate because it does not require stomach acid to absorb. This is worth discussing with your GP.
Which calcium-rich foods are best if you take PPIs?
Dairy products, tinned fish with bones, fortified plant milks, and calcium-set tofu all provide calcium that still needs some stomach acid to absorb, but is far less affected by reduced acid than calcium carbonate supplements.
If you would like help making sense of your own situation, our bone health resources explain the nutrition side in plain terms, alongside the medical care your GP or specialist provides.
Structured guidance for bone health
If you’re looking to build a clearer understanding of supporting bone health while taking a PPI, the Nutrition for Bone Health Guide explains it in a structured and practical way.
If you would prefer to explore how this applies to your own situation, one-to-one support with Laura provides personalised guidance alongside your medical care.
Disclaimer
The information in this article is for general educational purposes. It is not intended to diagnose, treat, or replace medical advice. Do not change, reduce, or stop any prescribed medication without discussing it with the clinician who prescribed it. Bone health is influenced by many factors, and individual circumstances vary.
If you have been diagnosed with osteopenia or osteoporosis, or are taking medication that affects bone health, continue to work with your GP, consultant, or specialist team. Nutritional therapy is intended to support, not replace, medical care.
For personalised guidance, consult a registered nutritional therapist or other qualified health professional who can assess your full clinical picture.
References
Recker RR. Calcium absorption and achlorhydria. New England Journal of Medicine. 1985. https://www.osti.gov/biblio/5012897
Liu J, et al. Proton-pump inhibitors and risk of fractures: an update meta-analysis. Osteoporosis International. 2016;27:339 to 347. https://link.springer.com/article/10.1007/s00198-015-3365-x
National Institute for Health and Care Excellence. Osteoporosis: assessing the risk of fragility fracture (CG146). 2017. https://www.nice.org.uk/guidance/cg146/chapter/Recommendations
Medicines and Healthcare products Regulatory Agency. Proton pump inhibitors in long-term use: reports of hypomagnesaemia. Drug Safety Update, April 2012. https://www.gov.uk/drug-safety-update/proton-pump-inhibitors-in-long-term-use-reports-of-hypomagnesaemia
NHS. Vitamin D. https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
Jung SB, et al. Proton Pump Inhibitors, H2-Receptor Antagonists, Metformin, and Vitamin B-12 Deficiency: Clinical Implications. Advances in Nutrition. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6054240/
