Low B12 After 50: How Metformin and Acid Reducers Can Drain It
Bloating & DigestionArticleTiredness, tingling feet and memory slips can come from low vitamin B12, which affects up to 43% of older adults. Metformin's label now advises checking B12 every 2 to 3 years, and the NIH warns that acid-reducing medicines can block absorption from food. Here is who should be tested and what helps.
Vitamin B12 keeps your blood and nerve cells healthy.1 Adults need 2.4 micrograms a day.1 Yet low B12 affects somewhere between 3% and 43% of older adults, depending on the study.1
Why it gets harder after 50
Many older adults don’t make enough stomach acid to free B12 from food.1 That’s why the NIH advises that people over 50 get most of their B12 from fortified foods or supplements, which are absorbed more easily.1 Two autoimmune conditions, atrophic gastritis and pernicious anemia, also block absorption; pernicious anemia is usually treated with B12 shots.1 Our guide to atrophic gastritis follow-up covers that condition.
Medicines that lower B12
Metformin. In trials, about 7% of people developed low B12 within about 7 months.2 The label now says to check blood counts yearly and B12 every 2 to 3 years.2 Low levels reversed with supplements or stopping the drug.2 People with low calcium intake may be more prone.2
Acid reducers. Proton pump inhibitors such as omeprazole and H2 blockers reduce stomach acid, which can interfere with absorbing B12 from food.1 Our article on stopping long-term acid reducers explains when to reassess them.
Symptoms to watch for
Symptoms can take years to appear because the body stores a lot of B12.1
- Tiredness or weakness from anemia1
- Numb or tingly hands and feet1
- Balance problems, low mood or confusion1
These overlap with many other conditions, so testing matters.
What helps
- Get tested if you take metformin, use acid reducers long term, or have symptoms.
- Choose fortified foods or a supplement if you’re over 50.1 Plant foods have no B12 unless fortified.1
- Ask whether you need shots if absorption is the problem.1
Try: “I’ve taken metformin and omeprazole for five years and my feet tingle. Can we check my B12 level?”
Bloated by Dinner includes a Belly Clock log and a Test-It list with a visit script. Use them to list every acid reducer and diabetes medicine you take and how long you’ve taken them. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please don't stop metformin or an acid-reducing medicine without talking to your prescriber. Numbness, weakness, trouble walking, confusion or memory changes should be evaluated, since low B12 is only one possible cause. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses a drug label and federal nutrition guidance. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- NIH Office of Dietary SupplementsVitamin B12: Fact Sheet for Consumers (opens in a new tab)abcdefghijklmn
- DailyMed, National Library of MedicineMetformin hydrochloride tablets: prescribing information (opens in a new tab)abcd
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