The inability to digest lactose, a sugar found in dairy products.
Adverse reactions to gluten-containing grains, like wheat, without having celiac disease.
Difficulty digesting fructose, often found in fruits, honey, and some sweeteners.
Inability to break down histamine, found in aged and fermented foods, leading to allergy-like symptoms.
Sensitivity to the stimulant caffeine, found in coffee, tea, and some soft drinks.
Reactions to sulfites, often used as preservatives in foods and beverages.
Sensitivity to natural chemicals called salicylates found in various fruits, vegetables, and spices.
Difficulty digesting fermentable carbohydrates found in many foods, causing gastrointestinal distress.