Histamine is a naturally occurring biogenic amine that serves as a neurotransmitter and is involved in the body’s immune response. In people with histamine intolerance (HIT), the body cannot effectively break down histamine consumed from food, often due to insufficient activity of the enzyme diamine oxidase (DAO). When histamine intake exceeds the body’s capacity for degradation, it builds up, triggering symptoms resembling an allergic reaction, such as headaches, hives, or digestive issues. This condition prompts questions about the histamine content of common foods, including wheat. This article examines the histamine status of wheat, differentiating its raw state from its processed forms.
The Baseline Histamine Status of Wheat
Raw, unprocessed wheat, such as wheat berries or freshly milled flour, is generally considered a low-histamine food. Unlike fermented or aged foods, grains in their natural state contain minimal levels of biogenic amines. Scientific analysis typically shows a very low histamine content, often around 0.12 milligrams per kilogram. This low concentration means consuming fresh, unadulterated wheat is unlikely to trigger symptoms based purely on its inherent load.
The structure of the raw grain does not facilitate significant histamine production. Histamine is primarily created through the decarboxylation of the amino acid histidine by certain microbial enzymes. Since raw wheat does not undergo microbial aging or fermentation, this conversion process is absent.
Furthermore, raw wheat is not classified as a histamine-releasing food, meaning it does not typically provoke mast cells to release stored histamine. For individuals managing HIT, the grain itself is not the primary concern; the problem arises when the wheat is subjected to various forms of processing and preparation.
How Processing and Preparation Affect Histamine Levels
The vast majority of wheat consumed is incorporated into baked goods, where processing dramatically alters its histamine content. Bread-making processes, particularly fermentation, introduce microorganisms that generate biogenic amines. The conversion of the amino acid histidine into histamine occurs during the leavening stage due to this microbial activity.
Yeast and Commercial Bread
Traditional bread made with commercial baker’s yeast has a relatively short fermentation time, limiting histamine formation. Certain strains of lactic acid bacteria (LAB) often present in the dough, rather than the yeast itself, are the main culprits for histamine production. Using commercial yeast in quick-rise doughs generally results in a lower histamine load compared to more complex preparation methods.
Sourdough Fermentation
Sourdough bread relies on a symbiotic culture of yeast and various LAB, presenting a complicated scenario for HIT. While the long fermentation process can break down components like FODMAPs, the prolonged bacterial activity can simultaneously lead to a greater accumulation of biogenic amines. The exact histamine level in sourdough is highly variable, depending on the specific bacterial strains, temperature, and duration of fermentation.
Storage Time
Storage time also influences the histamine content of wheat-based products. As baked goods age, the potential for microbial growth and the resulting increase in histamine levels rises. Products that have been sitting on a shelf for an extended period may contain higher concentrations of histamine than fresh items. Freezing can help mitigate this effect by halting the microbial activity responsible for amine formation.
Distinguishing Wheat Sensitivity, Celiac Disease, and Histamine Intolerance
A negative reaction to wheat is common, but it is frequently misattributed to histamine or a single cause. Celiac disease, Non-Celiac Gluten Sensitivity (NCGS), and Histamine Intolerance are distinct conditions with overlapping symptoms, which often leads to confusion.
Celiac Disease
Celiac disease is an autoimmune disorder where gluten triggers an immune response that damages the small intestine lining. This damage, known as villous atrophy, impairs nutrient absorption and can indirectly affect histamine metabolism. The associated inflammation may compromise the production of the DAO enzyme, which is primarily made in the gut, potentially creating a secondary histamine intolerance. Diagnosis is confirmed through specific blood tests for antibodies and intestinal biopsy.
Non-Celiac Gluten Sensitivity (NCGS)
NCGS is a condition diagnosed when individuals experience symptoms after consuming gluten-containing foods, but celiac disease and wheat allergy have been ruled out. While the mechanism is less defined than celiac disease, some reactions may be due to wheat’s fermentable carbohydrates, known as fructans (a type of FODMAP). Fructans are poorly absorbed in the small intestine and are fermented by gut bacteria, causing symptoms like bloating and pain.
The symptoms of NCGS and fructan intolerance, such as gastrointestinal distress, headache, and fatigue, are similar to those of HIT. Differentiating between these conditions requires a targeted diagnostic approach, focusing on the immune response to gluten, the body’s ability to degrade histamine via the DAO enzyme, or a reaction to the fermentable sugars in the wheat. Simply avoiding wheat may alleviate symptoms, but it does not clarify the underlying physiological cause.