Based on NIH | Is there evidence that eating blueberries while taking omeprazole increases the risk of side effects?

There is no clinical evidence that eating blueberries while taking omeprazole increases the risk of side effects. Most official guidance on omeprazole interactions focuses on certain prescription drugs and a few herbal products, and it does not list blueberries or common berries as a concern. ^[1] Omeprazole’s known interaction issues include medicines such as clopidogrel, methotrexate, rifampin, and St. John’s wort, but foods like blueberries are not highlighted. ^{[2] [3]}

What is known about omeprazole interactions

• Omeprazole (a proton pump inhibitor) can change how other drugs work primarily by two mechanisms: raising stomach pH (which can reduce absorption of drugs that need acid) and inhibiting a liver enzyme called CYP2C19 (which can increase levels of drugs metabolized by that enzyme). ^{[4] [5]}
• Official labels emphasize avoiding or monitoring for interactions with specific drugs (for example, clopidogrel and some antifungals), not with fruits. ^{[2] [3]}

What about blueberries and CYP2C19?

• Blueberries contain natural pigments called anthocyanins and related polyphenols. In lab (test-tube) experiments, some berry constituents can inhibit CYP2C19, but their inhibitory strength is much weaker dozens to hundreds of times than standard drug inhibitors, and these findings are in vitro, not in people. This suggests that typical dietary amounts of berries are unlikely to cause a meaningful interaction with CYP2C19 in real‑world use. ^[6]

Practical implications for side effects

• Because blueberries are not recognized as a clinically relevant interacting food for omeprazole and any potential enzyme effects from normal dietary intake appear minimal, eating blueberries would not be expected to raise the risk of omeprazole side effects for most people. ^{[1] [2]}
• If blueberries are taken as high‑dose extracts or concentrates (supplements), the situation could be different, but there is still no human evidence showing increased omeprazole adverse effects due to such products; caution is reasonable with any concentrated supplement due to theoretical enzyme effects. ^[6]

When to be cautious

• If you take medications that are highly sensitive to CYP2C19 or to stomach acid changes, your clinician may already be monitoring for interactions due to omeprazole itself; blueberries are not among the routine concerns in these scenarios. ^{[5] [4]}
• If you experience new symptoms while on omeprazole such as significant stomach pain, persistent diarrhea, severe headaches, or signs of low magnesium these are known potential issues with longer‑term PPI use and should be evaluated, regardless of fruit intake. ^{[7] [3]}

Bottom line

Based on current labeling and available evidence, blueberries in typical food amounts do not appear to increase the risk of side effects from omeprazole. ^{[1] [2]} If you are considering blueberry extracts or high‑dose berry supplements, discuss this with your healthcare professional because concentrated products may have different effects than whole fruit, even though clear clinical interactions with omeprazole have not been demonstrated. ^[6]