Black olives

Black olives are high in histamine. Every olive has to be cured or brined before it is edible, and those curing and brining steps are exactly what this index rates high, including the canned black olives you find on pizza and in salads.

Why black olives are rated high

A raw olive off the tree is so bitter it is inedible, so there is no such thing as a fresh, uncured olive on your plate. Getting an olive edible means curing it in brine, in lye, or by dry salting, and many types ferment during that process. Fermentation and long salt-brining give histamine-forming bacteria time to work, and the finished olive sits in that brine right up until you eat it. Canned black olives are typically lye-cured and packed in brine, and the label rarely tells you whether they fermented, so they land in the high column across the board.

What changes your risk

• Curing method — Genuinely fermented, salt-brined, or Greek-style oil-cured olives tend to run higher, while quick lye-cured canned ripe olives are milder, but neither is a low-histamine food and you usually cannot tell from the tin.
• Brine time — The longer an olive sits in salt brine, the more chance bacteria have had to build histamine, and most olives have been in brine for weeks or months by the time you buy them.
• Rinsing — Draining and rinsing canned olives washes off surface brine and a little of what is dissolved in it, but it does not remove histamine that has already formed inside the olive.
• Leftovers and storage — Once opened, olives keep sitting in brine in the fridge, and an already-preserved food can climb higher the longer it is held, so a jar that has been open for weeks is a worse bet than a freshly opened one.
• Portion — A few olives on a salad still count. Amount does not make a high-histamine food low, but a small garnish is a smaller load than a bowl of them as a snack.

Lower-histamine alternatives

There is not a great like-for-like swap, because olives are inherently a cured food. For the salty, savory hit in a salad or on a plate, reach for genuinely low-histamine options instead: fresh cucumber, sliced radish, roasted red or yellow bell pepper (freshly cooked, not jarred in vinegar), or lightly salted fresh vegetables with olive oil. Olive oil itself is fine and gives you that olive flavor without the cured fruit. Skip the obvious-looking cousins that are also high: green olives, capers, and anything brined or pickled in the same way.

How to lower the risk

If you do keep olives around for others, buy them in small quantities so a jar is not open for long, and store them cold in their brine. Draining and rinsing before use is worth doing to cut the surface saltiness, but treat it as a small improvement, not a way to make them safe. When you are building a dish for yourself, leave the olives off and lean on olive oil, fresh herbs, and fresh crunchy vegetables for flavor instead.

Common questions

Are black olives lower in histamine than green olives?

Not in a way you can rely on. Both are cured or brined before eating, and this index rates them both high. The color mostly reflects ripeness and processing, not histamine content.

Does rinsing canned olives remove the histamine?

No. Rinsing washes off surface brine and some salt, but histamine that formed during curing and brining is inside the olive and stays there.

Are olives on pizza a problem?

Yes, the canned black olives on pizza are the same high-histamine cured olives, so it is best to ask for them left off.

Is olive oil high in histamine too?

No. Olive oil is generally well tolerated and is a good way to get olive flavor without eating the cured fruit.