Green tea

Green tea is rated moderate and carries the DAO Blocker tag. The leaves are unoxidized, but SIGHI names green tea alongside black tea in its restricted column and marks it as a possible blocker of the enzymes that break down histamine.

Why green tea is rated moderate

Green tea comes from Camellia sinensis and is unoxidized, since the leaves are heated soon after picking, which is what keeps the cup pale and grassy. That lighter processing does not move it on this index. SIGHI's food list names black tea and green tea together in its restricted column and marks both as possible blockers of DAO, the enzyme that breaks down histamine from food. So green tea is rated moderate with the DAO Blocker tag: it may slow the breakdown of histamine, which matters most when a meal has histamine in it to clear. The listing comes from patient reports rather than a measured effect on the enzyme, and many people with histamine intolerance drink it daily without trouble.

What changes your risk

• Plain leaf or a blend: Bottled and flavored green teas often add citrus and sweeteners, and citrus is rated a histamine liberator on this index. Plain single-ingredient leaf is simpler to judge than a blend.
• Time of day: Green tea contains caffeine. Caffeine raises adrenaline, which can produce flushing, a racing heart or jitters that overlap with histamine symptoms, and late-day caffeine can disrupt sleep.
• Steeping: A shorter steep in cooler water is something people choose, and it makes a lighter cup. It does not change the moderate rating or the DAO Blocker tag.
• Loose leaf or bags: Both are Camellia sinensis, so the form the tea comes in does not change the rating or the tag.
• Decaf: Decaffeination removes most of the caffeine, and SIGHI does not identify caffeine as the DAO mechanism, so decaf green tea keeps the moderate rating and the DAO Blocker tag.

Lower-histamine alternatives

Peppermint and lemongrass are the closest light, fresh infusions, and chamomile, lemon balm, fennel seed and fresh ginger are all rated low here with no tags. Rooibos covers you when you want something fuller, red-brown in the cup and able to take milk. SIGHI puts herbal teas and rooibos nature in its well tolerated column. See the site's low histamine tea recipes for caffeine-free versions.

How to lower the risk

Plain loose leaf brewed at home is the version of green tea that is easiest to judge, since bottled and flavored green teas often bring citrus and sweeteners with them. Store the leaf sealed and dry. If you are looking for a caffeine-free cup with a similar light character, peppermint and lemongrass are rated low on this index, and rooibos gives you something fuller.

Common questions

Is green tea a DAO blocker?

It carries that tag here. SIGHI marks green tea as a possible blocker of DAO, the enzyme that breaks down histamine from food, so green tea may slow the breakdown of histamine. The listing comes from patient reports, and many people tolerate green tea daily.

Is green tea better than black tea for histamine intolerance?

SIGHI names both in the same restricted column, and both are rated moderate here with the DAO Blocker tag.

Why is green tea rated moderate when it is unoxidized?

Oxidation is not what the rating follows. Green tea is Camellia sinensis, and SIGHI marks it as a possible blocker of the enzymes that break down histamine.

What can I drink instead of green tea?

Peppermint, lemongrass, chamomile, lemon balm, fennel seed, fresh ginger and rooibos are rated low here with no tags, and SIGHI places herbal teas and rooibos nature in its well tolerated column.