onion
Vegetables
Is onion high in caffeine?
Is onion high or low in caffeine? See its exact rating, how much counts as a portion, and its FODMAP, salicylate, oxalate and diet compatibility in one place.
Related checkers
Compare onion across criteria
Sensitivity notes
Why caffeine food checker matters
Caffeine is a natural stimulant found in coffee, tea, chocolate, and many soft drinks. While safe for most people, those with caffeine sensitivity may experience anxiety, rapid heartbeat, digestive issues, or sleep disturbances even from small amounts.
- Gradually reduce caffeine to avoid withdrawal headaches
- Switch to decaf versions of your favorite drinks
- Be aware of hidden caffeine in chocolate and some medications
- Try herbal alternatives like rooibos or peppermint tea
- Caffeine sensitivity can change with age and stress levels
Sensitivities
What onion contains
FODMAPs
Histamine & Amines
Plant compounds
Irritants
Additives
Allergens
Diet fit
Where onion fits
Therapeutic diets
Lifestyle diets
Religious diets
What to know about onion
Onion is graded E for fructans and E for total FODMAPs, the top of our scale, which is why it is the single most common trigger people uncover once they start logging food against symptoms. The reaction is a carbohydrate problem rather than an allergy: onion is A for histamine, A for oxalates, A for lectins and A for nightshades, so if onion bloats you the fructans are almost certainly the mechanism. It also grades E for low fermentation SIBO plans. The frustrating part is that fructans are water soluble and heat stable, so caramelizing, slow simmering or fishing the pieces out of a sauce does not make onion any safer, and onion hidden in stock, gravy and spice blends is why so many people react to restaurant food they cannot account for.
Watch for
- Fructans and total FODMAPs both graded E, the highest tier we use, and the grade does not soften between raw and cooked onion
- Cooking is not a fix: fructans dissolve out of the onion into the pan and stay in the liquid, so straining the pieces out leaves the trigger in the sauce
- Hidden onion drives most unexplained flare-ups: stock cubes, gravies, curry pastes, spice rubs, chips and anything listed as seasoning or natural flavor
- Graded E for low fermentation SIBO, so onion is usually one of the first things pulled when working through a SIBO protocol
- Clean on the rest of the chemistry (histamine A, oxalate A, lectin A, nightshade A, with only a borderline B for histamine liberation), which is why an onion reaction is nearly always intolerance rather than allergy
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Caffeine Guide
Everything you need to know about caffeine sensitivity and smart food choices.
Caffeine is a natural stimulant found in coffee, tea, chocolate, and many soft drinks. While safe for most people, those with caffeine sensitivity may experience anxiety, rapid heartbeat, digestive issues, or sleep disturbances even from small amounts.
Sensitivity varies widely. What triggers one person may be fine for another. Track your reactions to find your personal threshold.
These foods have moderate levels and may be tolerated in small amounts:
These foods are high in caffeine and may trigger symptoms:
If you're sensitive to Caffeine, consider these strategies:
- 1Gradually reduce caffeine to avoid withdrawal headaches
- 2Switch to decaf versions of your favorite drinks
- 3Be aware of hidden caffeine in chocolate and some medications
- 4Try herbal alternatives like rooibos or peppermint tea
- 5Caffeine sensitivity can change with age and stress levels
Pro tip: Keep a food diary to track your reactions. The Triggerbites app makes this easy with automatic pattern detection.
Want personalized tracking?
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Get the AppFAQ
Is onion high in Caffeine?
Caffeine: low signal for most people.
Can I still eat onion if I'm sensitive to Caffeine?
Usually fine in normal portions.
What else should I check?
Check FODMAPs, Fructans, and Low Fermentation next for a fuller picture.