Overview
About Longan
Longan sits at the top of our FODMAP range: E for total FODMAPs, E for excess fructose, D for polyols and E for low-fermentation SIBO protocols.
That combination is unusual, because most fruit is high on one axis and mild on the others, whereas longan is loaded on fructose and polyols at once. Practically, that means the failure mode is not one longan, it is the handful, and longan is a fruit almost nobody eats singly. Dried longan makes it worse in the obvious way: drying strips the water and concentrates the same sugars, so the dried fruit used in Chinese soups, teas and desserts carries a much larger FODMAP dose per gram than the fresh fruit does. Outside the gut it is quiet, with A grades for histamine, tyramine, gluten, glutamates, sulfites and oxalates and only mild B grades for salicylates, nickel and histamine liberation. It is worth knowing that longan is in the soapberry family alongside lychee and ackee, the family behind the unripe-fruit hypoglycin story, though the measured picture for longan is reassuring rather than alarming.
Sensitivities
How Longan scores
Watch for
What trips people up
- E for total FODMAPs and E for excess fructose, the strongest fructose grade we assign, so fructose malabsorbers tend to react to longan faster and at smaller amounts than to most fruit
- D for polyols on top of that, which is why symptoms often show up as osmotic diarrhoea rather than just gas
- E for low-fermentation SIBO protocols: exclude it during an elimination phase rather than trying to find a tolerable portion
- Dried longan is the concentrated version of the same problem. A small handful of dried fruit or a bowl of longan dessert soup is a much bigger FODMAP dose than the equivalent weight of fresh longan
- Canned longan in syrup adds free sugar on top of the fruit sugars and is a poor test food if you are trying to work out your own threshold
Diet fit
Where it fits
Swap ideas
More alternatives
FAQ
Common questions about Longan
Is longan high FODMAP?
Yes, and it is one of the highest we track. Longan grades E for total FODMAPs, E for excess fructose and D for polyols. The fructose grade is the headline: it means the fruit contains substantially more fructose than glucose, which is the specific pattern that overwhelms fructose absorption in the small intestine. A very small serving of a few fruits is where any tolerance testing should start, and dried longan should be left out of testing entirely because the dose per gram is so much higher.
Is longan the same as lychee?
No, but they are close relatives in the soapberry family and they behave almost identically in our grading: both are E for total FODMAPs, E for excess fructose, D for polyols and E for SIBO protocols. Longan is smaller, tan-skinned and smooth where lychee is red and rough, and the flavour is more musky and less floral. If lychee reliably triggers you, longan is not the safe alternative it looks like on a fruit platter.
Does longan contain the same toxin as unripe lychee?
Only in trace amounts, and the difference is real. The illness outbreaks associated with lychee involved children eating large quantities of unripe fruit on an empty stomach, where hypoglycin A and MCPG interfere with the body making glucose overnight. When researchers measured both compounds across soapberry fruits, longan arils contained hypoglycin A at roughly one to two and a half micrograms per gram of dried fruit while MCPG fell below the reporting limit, against lychee readings up to about twenty one micrograms per gram. Ripe longan eaten as a normal food is not part of that story. The reason to moderate longan is its sugar and FODMAP load, not this.
Is longan a problem for histamine intolerance?
It is not a histamine food. Longan grades A for histamine content and A for tyramine, with a mild B for histamine liberation that matters only to people who react across many fruits. Dried longan is a different question of degree rather than kind: drying does not add histamine to fruit, but any dried fruit that has been stored badly or treated with sulfur is worth checking, and preserved longan products vary a lot by producer.
References
Read the background
Ratings reflect the Triggerbites ingredient database and may vary with portion size and preparation.