PPIs and nutrition

The vitamin nobody mentioned: PPIs and B12

If you've taken reflux tablets for years, it's worth knowing what they can do to your B12, and what to ask your doctor.

Of all the things I wish someone had told me when I was first handed a prescription for PPIs, this is near the top of the list.

Vitamin B12 is a nutrient your body can't make. You get it from animal foods such as meat, fish, eggs and dairy, and it's essential for making healthy red blood cells, keeping your nerves working properly and supporting your brain. But getting B12 out of your food depends on the very thing PPIs are designed to switch off: stomach acid.

How it works

In food, B12 is locked onto proteins. Stomach acid and the digestive enzyme pepsin prise it loose. Only then can it pair up with intrinsic factor, a protein made by the stomach lining, and travel to the end of the small intestine, where it's absorbed. Turn the acid down for months or years, and less B12 is freed from your food in the first place.

What the research found

In 2013, researchers at Kaiser Permanente in California published a large study in the Journal of the American Medical Association. They compared almost 26,000 people newly diagnosed with B12 deficiency against more than 184,000 people without it.

The link weakened after people stopped the medication. H2 blockers such as famotidine showed a smaller but still significant link. It's an observational study, so on its own it can't prove that PPIs caused every case, but a dose-response pattern combined with a well-understood mechanism makes it hard to dismiss.

My experience

I was on PPIs for fifteen years. I only learned about this long after I'd come off them, when someone asked the question in a GERD support group and the replies kept coming: me too.

I'm one of them. Nearly ten years after my last tablet, I still can't absorb enough B12 from food. Injections bring my levels back up, which tells me my body can use B12 once it gets in; the problem is getting it through my gut. In fifteen years of repeat prescriptions, nobody ever told me it was something to watch for.

Symptoms to look out for

Low B12 often creeps up slowly, and the early signs are easy to blame on stress, age or simply being run-down:

• Tiredness that rest doesn't fix
• Pins and needles or numbness in the hands and feet
• Brain fog, poor memory or difficulty concentrating
• Low mood, irritability or anxiety
• Breathlessness or feeling light-headed
• A sore, red or smooth tongue, or mouth ulcers
• Pale or slightly yellowish skin
• Problems with balance or coordination
• Changes in vision

Why it matters

Left untreated, B12 deficiency can cause megaloblastic anemia, where the body makes fewer, larger and less effective red blood cells. That leaves you exhausted and breathless, and in severe cases puts extra strain on the heart.

More seriously, B12 protects the nerves and spinal cord. A prolonged deficiency can cause nerve damage, numbness, weakness and problems with walking and balance, and some of that damage can become permanent if it isn't treated in time. It can also cause memory problems, confusion and depression; in older people this can be mistaken for dementia. Low B12 before and during pregnancy is linked to a higher risk of neural tube defects in the baby.

The good news: most of these problems respond well to treatment when they're picked up early.

What you can do

Reference: Lam JR, Schneider JL, Zhao W, Corley DA. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA. 2013;310(22):2435–2442. View on PubMed