Squash is generally considered a low-histamine food. On the SIGHI food compatibility list, one of the most widely referenced guides for histamine intolerance, both squash and zucchini receive a rating of 0, the lowest possible score, meaning they are well tolerated by most people with histamine sensitivities. Fresh squash of all varieties is a safe staple for the majority of people following a low-histamine diet.
Histamine and Amine Levels in Squash
Lab testing confirms what the food lists suggest. In courgette (zucchini), histamine itself was not even detectable. Pumpkin showed only trace amounts, averaging 0.28 mg/kg of fresh weight, with some samples registering none at all. Tyramine, another amine that can cause symptoms in sensitive individuals, was not detected in either variety.
Squash does contain moderate levels of putrescine, a different biogenic amine that can compete with the same enzyme your body uses to break down histamine. Zucchini averages about 8 mg/kg and pumpkin about 10 mg/kg. These levels are far lower than high-putrescine foods like citrus fruits or fermented products, but they’re worth knowing about if you’re highly sensitive. Cadaverine levels in both varieties are negligible, well under 1 mg/kg on average.
Summer vs. Winter Squash
There is no meaningful difference in histamine content between summer squash (zucchini, yellow squash, pattypan) and winter squash (butternut, acorn, delicata, spaghetti squash). Both categories score the same on histamine food lists, and lab data on their biogenic amine profiles is comparable. The key factor is freshness. Like all vegetables, squash can develop higher amine levels as it ages or sits after being cut. Cooking and eating squash while it’s fresh keeps amine levels at their lowest.
One food list from a urology practice categorizes squash (both summer and winter, excluding pumpkin) as “highly individual,” meaning some people tolerate it perfectly while others notice mild reactions. This is a more cautious classification than the SIGHI list, and it reflects the reality that histamine intolerance varies widely from person to person.
Pumpkin and Pumpkin Seeds
Pumpkin is a close relative of other winter squashes and has a similarly low histamine profile, though its trace histamine levels (up to 1.9 mg/kg in some samples) are slightly higher than zucchini. For most people with histamine intolerance, this amount is insignificant, but if you notice symptoms with pumpkin that you don’t get with other squash, those trace amines could be the reason.
Pumpkin seeds are a separate consideration. Seeds and nuts in general tend to be more variable in their amine content than fresh vegetables, and some histamine-conscious food lists flag them as foods to test individually rather than assume are safe. If you tolerate pumpkin flesh without issues, try a small portion of the seeds on their own to gauge your response.
A Note on Salicylates
Some people managing histamine intolerance also react to salicylates, naturally occurring compounds found in many plant foods. Squash and zucchini both fall into the higher-salicylate category for vegetables. If you’ve noticed that your symptoms don’t fully resolve on a low-histamine diet alone, salicylate sensitivity could be a contributing factor. This doesn’t change squash’s status as low-histamine, but it’s a common overlap worth being aware of.
How to Include Squash in a Low-Histamine Diet
Fresh squash is one of the most versatile vegetables available on a restricted diet, and a few simple habits will keep it as low in amines as possible:
- Buy whole, uncut squash when you can. Pre-cut squash sold in plastic wrap has more surface area exposed to air, which accelerates amine formation.
- Cook it soon after cutting. Once you slice into a squash, use it within a day or two rather than letting it sit in the fridge.
- Freeze leftovers immediately. Cooked squash stored in the fridge will slowly accumulate amines over several days. Freezing halts that process.
- Skip canned or jarred squash. Preserved vegetables sit in liquid for extended periods, which can raise amine levels compared to fresh preparation.
Roasted butternut squash, sautéed zucchini, baked spaghetti squash, and pureed acorn squash are all well-tolerated options for most people on a low-histamine protocol. Because individual thresholds vary, introducing one variety at a time and watching for symptoms over 24 hours gives you the clearest picture of your personal tolerance.