Low-histamine soy products

Is soy high in histamine? Plain soy is not, in the studies we use, while fermented soy is the highest-histamine food group a University of Barcelona team measured. The difference is the fermentation, not the bean.

Five samples of soybeans sold in Spain had no detectable histamine, and neither did six samples of tofu. A study collected in the team's 2018 review found none in three samples of soy milk. Soybeans do carry other amines: putrescine averaged 19.07 mg/kg and cadaverine 9.04 mg/kg, along with 99.55 mg/kg of spermidine, a polyamine, the highest spermidine average in the team's 2021 table. Tofu had much less, with putrescine averaging 0.76 mg/kg, and soy milk 1.02 mg/kg.

Fermented soy is a different food. The team's 2021 table reports 21 samples of "soy-fermented products" with histamine averaging 73.95 mg/kg, the highest average of any food group in it, above sauerkraut (43.74 mg/kg) and cured cheese (33.10 mg/kg). Some samples had none, but 5% were above 486.31 mg/kg and the highest reached 730.06 mg/kg. Tyramine averaged 187.24 mg/kg. The paper does not say which products the 21 samples were, so tempeh and miso are rated here from the group figure and labelled "measured as a food group". Soy sauce is another fermented soy product and has its own page.

The published diets lean the same way, but more gently than the measurements. Of the ten diets charted in the 2021 review, one excludes soybeans and four exclude soy-fermented products. An earlier review from the same group found soybeans excluded by fewer than 20% of diets and fermented soy derivatives by 20–60%. A 2024 clinical review lists fermented soybean products among the foods a low-histamine diet avoids.

Edamame, the young green soybean, was not measured at all, and its page says so. Soybean sprouts were tested only for other amines, and had more putrescine than the mature beans. Each page below lists what was measured, how many samples sit behind each number, and the forms that were not tested, such as smoked tofu, fermented tofu, soy yogurt and miso soup.

Sources

1. Sánchez-Pérez S, Comas-Basté O, Veciana-Nogués MT, Latorre-Moratalla ML, Vidal-Carou MC. Low-Histamine Diets: Is the Exclusion of Foods Justified by Their Histamine Content? Nutrients 13(5):1395, 2021. doi:10.3390/nu13051395
2. Sánchez-Pérez S, Comas-Basté O, Rabell-González J, Veciana-Nogués MT, Latorre-Moratalla ML, Vidal-Carou MC. Biogenic Amines in Plant-Origin Foods: Are They Frequently Underestimated in Low-Histamine Diets? Foods 7(12):205, 2018. doi:10.3390/foods7120205
3. Comas-Basté O, Sánchez-Pérez S, Veciana-Nogués MT, Latorre-Moratalla M, Vidal-Carou MDC. Histamine Intolerance: The Current State of the Art. Biomolecules 10(8):1181, 2020. doi:10.3390/biom10081181
4. Jochum C. Histamine Intolerance: Symptoms, Diagnosis, and Beyond. Nutrients 16(8):1219, 2024. doi:10.3390/nu16081219