Is Decaf Coffee Good for You? Sleep, Acidity and Pregnancy, Answered

Written by Tiny Tiger Coffee

It's 9 pm. Dinner is done, someone puts the kettle on, and you'd love a coffee. Then the little voice starts. Will I sleep? Will it give me acidity? I'm pregnant, is even decaf okay? And isn't decaf full of chemicals anyway?

Fair questions. Here's what the evidence actually says. If you want to know how decaf is made in the first place, our decaf explainer tells that story.

First, what decaf takes away

Decaf is ordinary coffee with almost all the caffeine removed. Almost all, not all. The US FDA says a cup of decaf typically holds 2 to 15 mg of caffeine, against roughly 100 mg in a cup of instant coffee. Our guide to how much caffeine is in a cup of coffee has the full numbers.

So the honest way to think about decaf is this: it is coffee, minus the caffeine.

Decaf and sleep

This is where decaf helps most clearly.

Caffeine leaves your body slowly. In an average adult its half-life is about 5 hours, which means half of it is still working 5 hours after your cup. Think of it like a guest who leaves your party in stages.

• A 100 mg coffee at 6 pm still leaves about 50 mg in your system at 11 pm.
• A decaf with 5 mg leaves about 2.5 mg. That's next to nothing.

Does that matter? The European Food Safety Authority found that a single 100 mg dose close to bedtime may delay sleep and shorten it. In a study published in the Journal of Clinical Sleep Medicine, a large dose (400 mg) of caffeine taken six hours before bed cut sleep by more than an hour, and people didn't even notice.

So an evening decaf is a sensible swap. It won't fix sleep problems that have other causes, though.

Decaf and acidity

Here we need to be careful, because decaf is often sold as "acid-free". It isn't.

What the research shows:

• Decaf may cause less reflux. In a small study of 17 people with reflux disease, the time stomach acid spent in the food pipe after breakfast dropped from about 18% with regular coffee to about 3% with decaf.
• Decaf still makes your stomach produce acid. An older study in the New England Journal of Medicine found that decaf raised stomach acid nearly as much as regular coffee. Something other than caffeine is doing it.

So decaf may be easier on you if coffee gives you heartburn, but it may not. Some simple things to try:

• Drink it with food rather than on an empty stomach.
• Have a smaller cup.
• Notice your own pattern, and stop if it hurts.

If you get heartburn often, see a doctor. Changing your coffee is not a treatment.

Decaf in pregnancy

Caffeine passes to the baby, and late in pregnancy it stays in your body far longer, up to 15 hours for half of it to clear.

Three major authorities give the same limit:

• NHS (UK): no more than 200 mg of caffeine a day.
• EFSA (Europe): up to 200 mg a day raises no safety concerns for the baby.
• ACOG (USA): under 200 mg a day does not appear to be a major factor in miscarriage or preterm birth.

Two cups of filter coffee can use most of that. Even at the top of the FDA's range, four cups of decaf come to about 60 mg. Remember that tea, chocolate and cola count too. Your doctor knows your pregnancy best, so check with them.

Is the decaf process safe?

Most people worry about solvents. One common solvent, methylene chloride, is used in some decaf, and in the US the leftover amount in decaf coffee is capped at 10 parts per million.

Our Decaffeinated Toasted Almond avoids the question. It is decaffeinated with supercritical CO2, the same gas that puts bubbles in soda, and laboratory tests show a 99.95% caffeine reduction.

Does decaf have health benefits?

Possibly, but be wary of anyone who promises them. A large UK study of nearly 450,000 adults found that people who drank 2 to 3 cups of decaf a day had a lower risk of death and of heart disease over about 12 years. Decaf drinkers did not get the lower risk of irregular heartbeat seen with regular coffee.

That study shows a link, not proof. Decaf drinkers may simply live differently. What we can say is that decaf lets you keep the ritual, the flavour and the warm cup, without the caffeine.

Common questions

Can I drink decaf coffee at night?

Yes, for most people. Decaf holds only a few milligrams of caffeine, so an after-dinner cup is unlikely to keep you up.

Does decaf coffee cause acidity?

It can. Decaf seems to cause less reflux than regular coffee, but it still raises stomach acid. Try it with food and see how you feel.

Is decaf coffee safe during pregnancy?

Decaf keeps you far below the 200 mg daily limit set by the NHS, EFSA and ACOG. Check with your doctor about your own diet.

This article is general information, not medical advice.