CONDITIONS

Nutrient Malabsorption

You're taking supplements. You're eating well. But your levels aren't moving. Iron stays low. B12 stays low. Magnesium, zinc, calcium. The problem might not be what you're putting in. It might be what your stomach isn't doing.

Written by Michael D. Erdman, MBBS | Last reviewed: May 2026

Why stomach acid matters for absorption

Your stomach acid isn't just for digestion. It's essential for unlocking nutrients from food and making them available for absorption. Iron needs an acidic environment to convert into a form your body can use. B12 requires acid to be released from the proteins it's bound to in food. Calcium and magnesium absorption both depend on adequate stomach acidity.

When acid is low, these nutrients pass through your digestive system without being properly absorbed. You can take high-dose supplements and still see no improvement. The bottleneck isn't intake. It's upstream, in the stomach.

The pattern practitioners keep seeing

People with persistent nutrient deficiencies despite adequate supplementation. Iron infusions that provide temporary relief but levels that drop again. B12 injections because oral supplements don't absorb. Calcium supplementation that doesn't prevent bone density decline.

In many of these cases, nobody has looked at stomach acid. The assumption is that if you take the nutrient, it absorbs. But absorption requires the right environment. If your stomach isn't producing enough acid to create that environment, supplementation is working against a closed door.

How the Heidelberg test helps

The Heidelberg test measures your stomach acid in real time. For someone with persistent nutrient deficiencies, this answers a fundamental question: is your stomach creating the right environment for absorption?

If the test shows normal acid production, the malabsorption has a different cause. If it shows low acid, you and your practitioner have a clear starting point for addressing the root of the problem rather than endlessly supplementing around it.

What to do next

If your nutrient levels aren't responding to supplementation, a Heidelberg test can show whether your stomach acid is part of the equation. About an hour, no sedation, results the same day.

Ready to find out why nothing is absorbing?

One test. One hour. A definitive answer.

HEIDELBERG

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