From the Guidelines
An impaired response to histamines is typically caused by histamine intolerance, which can be addressed by reducing histamine intake, supporting histamine breakdown, and considering antihistamines. To address histamine intolerance, the following steps can be taken:
- Reduce histamine intake: Follow a low-histamine diet for 2-4 weeks, then gradually reintroduce foods to identify triggers.
- Support histamine breakdown: Take a diamine oxidase (DAO) enzyme supplement, 1-2 capsules before meals containing histamine, as recommended by the most recent study 1.
- Consider antihistamines: Use H1 blockers like loratadine (10mg daily) or H2 blockers like famotidine (20mg twice daily) as needed for symptom relief, with the preference for second-generation antihistamines due to their longer duration of action, less anticholinergic effects, and less sedation, as noted in 1.
- Address gut health: Probiotics containing Bifidobacterium species can help reduce histamine levels, take 1-2 capsules daily.
- Supplement with vitamin C (1000mg daily) and B6 (50-100mg daily) to support histamine metabolism.
Histamine intolerance occurs when the body cannot break down histamine efficiently, often due to reduced DAO enzyme activity or increased histamine production, leading to an accumulation of histamine and causing various symptoms like headaches, skin issues, or digestive problems, as discussed in 1. By reducing histamine intake and supporting its breakdown, you can improve your body's response to histamines and alleviate symptoms. It is essential to prioritize the use of second-generation antihistamines and be cautious with first-generation antihistamines, especially in older adults, due to their potential for sedation, performance impairment, and anticholinergic effects, as highlighted in 1.
From the Research
Impaired Response to Histamines
The cause of an impaired response to histamines can be attributed to several factors, including:
- A disequilibrium of accumulated histamine and the capacity for histamine degradation 2
- Low amine oxidase activity, particularly diamine oxidase (DAO) deficiency, which is the main enzyme for the metabolism of ingested histamine 2
- Impaired histamine degradation based on reduced DAO activity, resulting in histamine excess 2
- Ingestion of histamine-rich food or substances that release histamine or block DAO, such as alcohol or certain drugs 2
Histamine Intolerance
Histamine intolerance (HIT) is a common disorder associated with impaired histamine metabolism, characterized by a set of undesirable reactions resulting from accumulated or ingested histamine 3, 4. The manifestations of HIT can be caused by various pathophysiological mechanisms or a combination of them, making diagnosis challenging 3.
Role of Histamine in Immune Responses
Histamine plays a significant role in regulating immune responses, affecting chronic inflammation and several essential events in the immune response, including the regulation of immune cell functions and the recruitment of effector cells into tissue sites 5. The diverse effects of histamine on immune regulation are due to differential expression and regulation of its four receptors and their distinct intracellular signals 5.
Gut Mucosal Immune Regulation
Within the gastrointestinal tract, histamine has extensive effects on many cell types, mediated by the activation of its four receptors (H1R-H4R) 6. The effects of histamine on mucosal immune homeostasis are dependent on the expression and activity of these receptors, although the relative protective or pathogenic effects of histamine on inflammatory processes within the gut are still poorly defined and require further investigation 6.