Sources & methodology

Where our intolerance data comes from — and why you can trust it.

Wondering whether you can trust these ratings? Every intolerance level comes from published, peer-reviewed science — studies that actually measured how much of each compound (histamine, salicylates, FODMAPs, nickel…) is in real foods, not from guesswork. Here's exactly where the data comes from, and how we handle uncertainty.

Peer-reviewed science — measured food content, not default guesses.
Cautious when unsure — missing data means we flag, not reassure.
Independently sourced — built from the primary literature we cite.

FODMAPs, fructose, sorbitol, sucrose

FODMAP content varies by food and ripeness, so we use studies that measured fructans, polyols and sugars in specific foods.

Tuck C. et al. (2018). FODMAP content of common plant-based and processed foods. Journal of Human Nutrition and Dietetics.
Yao C.K. et al. Dietary sorbitol and mannitol: food content and absorption patterns. Journal of Human Nutrition and Dietetics.
Ma C. et al. (2014). Fructose, sorbitol, glucose and sucrose in fruits by HPLC-ELSD. Food Chemistry.
Lenhart A. et al. (2017). Polyols and gastrointestinal health / IBS: a systematic review. Advances in Nutrition.
L'homme C. et al. (2001). Fructans in fresh and stewed fruits (HPAEC-PAD). Journal of Chromatography A.
USDA — National Nutrient Database (FoodData Central).

Histamine & tyramine (biogenic amines)

Histamine and tyramine rise with fermentation and storage, so we rely on studies that measured amines in specific foods.

Marcobal A. et al. (2005). Histamine content of red wines (ELISA/HPLC). Food Research International.
Piersanti A. et al. (2014). Histamine in fish products — four years of official-control results. Food Chemistry.
Şenöz B. et al. (2000). Biogenic amines in Turkish sausages (sucuk). Journal of Food Science.
Blackwell B. et al. (1969). Histamine and tyramine content of yeast products. Journal of Food Science.
SIGHI — Swiss Interest Group Histamine Intolerance, food-compatibility list (cross-check).

Salicylates

Salicylates concentrate in herbs, spices and some fruits — taken from dedicated content studies.

Swain A. et al. — Friendly Food (RPAH Elimination Diet, Royal Prince Alfred Hospital).
Wood A. et al. (2011). A systematic review of salicylates in foods. Molecular Nutrition & Food Research.
Scotter M.J. et al. (2007). Free and acetyl salicylic acid in foods (GC-MS). Food Chemistry.
Paterson J.R. et al. (2006). Salicylic acid content of spices. Journal of Agricultural and Food Chemistry.
U.S. FDA — Total Diet Study.

Oxalates

Oxalate content differs widely between plants — taken from food-content tables.

Noonan S.C. & Savage G.P. (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition.
Ghosh Das S. et al. (2012). Total and soluble oxalate content of Indian spices. Plant Foods for Human Nutrition.
Nile S.H. et al. (2014). Oxalate and mineral content of edible mushrooms. Journal of Nutritional Disorders & Therapy.
Schröder T. et al. (2012). Oxalate content in cocoa and dark chocolate. Journal of Food Composition and Analysis.

Nickel

Nickel varies with soil and food type — from dietary nickel-content studies.

Flyvholm M.-A. et al. (1984). Nickel content of food and estimation of dietary intake. Z Lebensm Unters Forsch.
Zeiner M. et al. (2018). Harmful elements (incl. nickel) in wild berries and fruits. Toxics.
Amaro M. et al. (1998). Nickel content in cow's, ewe's and goat's milk. Lait.

Lactose

Lactose content comes straight from dairy composition tables.

USDA — National Nutrient Database (FoodData Central).
Ciqual — French food composition table (ANSES).

Gluten

Gluten is a yes/no: does the food contain a gluten grain (wheat, barley, rye)?

AFDIAG (France) & Coeliac UK — presence of gluten-containing cereals (wheat, barley, rye, contaminated oats).
Biesiekierski J. et al. (2013). Gluten and fermentable carbohydrates in non-coeliac gluten sensitivity. Gastroenterology.