Understanding Histamine Intolerance

By Emily Stubblefield, Texas State Dietetic Intern

Please note this post is for informational purposes only, and is not a replacement for seeking personalized medical advice from your physician, allergist, or registered dietitian.

If you have been experiencing unexplained digestive discomfort, persistent headaches, irritated skin, or anxiety-like symptoms you may be dealing with histamine intolerance. In this post, we’ll explore common symptoms of histamine intolerance, potential interactions and how you can approach this issue with the help of a registered dietitian (RD) or healthcare provider.

Histamine intolerance occurs when your body has a difficult time breaking down histamine, which is involved in immune responses and many body functions. Histamine intolerance is a complex issue that affects many individuals, causing a range of symptoms from digestive discomfort to headaches and anxiety-like responses¹. One of the key factors contributing to histamine intolerance is the activity of an enzyme known as diamine oxidase (DAO), which is responsible for metabolizing histamine². However, the relationship between DAO and histamine levels is not the only aspect to consider – the role of vitamin B6 in facilitating DAO’s function is critical and often overlooked.

The Mechanism Behind Histamine Intolerance

Histamine is a chemical messenger that plays a vital role in various pathways in the body, particularly in immune responses to allergens. When you consume foods that contain histamine, your body relies on DAO to break it down. Unfortunately, if DAO activity is low, histamine accumulates in the bloodstream, leading to what’s known as histamine intolerance ^2,3.

Symptoms of Histamine Intolerance^2,3

Histamine toxicity can manifest in several ways, including:

• Skin issues: itching, hives, and swelling (angioedema)
• Respiratory problems: nasal congestion and throat tightening
• Digestive issues: stomach upset, heartburn, and indigestion
• Neurological symptoms: headaches, fatigue, and anxiety-like feelings

Given that histamine intolerance lacks specific diagnostic criteria, it often goes unrecognized, complicating treatment efforts^2,3.

The Role of Vitamin B6 and DAO^4,5

Vitamin B6 (B6) also known as pyridoxine, is essential in brain development and plays a role in nervous and immune systems⁵. B6 isn’t produced by the body so it must be consumed through diet, thankfully it is found in many foods!

B6 has many beneficial factors that help the body function properly, such as:

• Antioxidant and anti-inflammatory properties that help to build
  •  DNA (carries genetic instructions for developmental, functional and reproduction)
  • Hemoglobin (carries oxygen in RBCs throughout the body)
  • Neurotransmitters (send signals from nerve cells to other cells) ⁵.
• Helps treat anemia by producing red blood cells, and shown to help treat sideroblastic anemia (rare, genetic condition that affects RBC production).
• Improves mood by producing neurotransmitters (serotonin) that can help regulate mood and aid in sleep and may have the potential to decrease anxious and depressive symptoms^5,6.
• Ease nausea during pregnancy and severe morning sickness (hyperemesis gravidarum).
• Early studies suggest a link between B66 and lowering the risks of colorectal cancer.

B6 and DAO Interaction

Research suggests that vitamin B6 plays a crucial role in the production and efficacy of DAO. DAO is dependent on cofactors including B6, copper, and zinc for optimal functionality^4,5. Rentzos et al, indicated there were significant differences in the symptom categories, specifically in gastrointestinal pain, skin symptoms, as well as in the total score for all symptoms between the low histamine diet (LHD diet) and the mixed diet (mix of low and high histamine foods)¹. Symptoms from the gastrointestinal tract (mpain) and skin (mskin) were found significantly higher (p< 0.05) during the mixed diet (MXD) compared to LHD¹.

B6 Deficiency

It’s essential to consume balanced meals regularly, as vitamin B6 is water-soluble and needs to be replenished frequently.  A B6 deficiencycan directly impair the body’s ability to produce adequate DAO, exacerbating histamine intolerance like symptoms^2,4. B6 deficiency has also been associated with inflammation and inflammation-related chronic illnesses (rheumatoid arthritis), and higher risk of death from coronary artery disease⁵. 

Therefore, adequate intake of vitamin B6 is essential for maintaining histamine balance in the body.

Here’s how you can boost your B6 levels through diet:

Good Sources of Vitamin B6⁵

1. Fish: Yellowfin tuna, sockeye salmon
2. Beef: Grass-fed beef liver
3. Tofu: Great plant-based protein source
4. Dairy: Cottage cheese and other dairy products
5. Eggs: Whole eggs are valuable sources
6. Legumes: Chickpeas and lentils
7. Fruit & Vegetables: Sweet potatoes, bananas, avocados, spinach

Daily Recommendations: According to the NIH, the upper limit for adults is 100mg per day⁷. Too much vitamin B6 from supplementation can be harmful and cause loss of body movement (ataxia), nausea or heartburn, peripheral neuropathy, sensory neuropathy or photosensitivity⁵.

Foods to Consider for histamine intolerance/sensitivity

Below, you will find a list of high Vitamin B6 foods, low histamine foods, and high histamine foods to consider.  

IMPORTANT: While some individuals have responded well to a low histamine diet plan, it should be used as a TEMPORARY adjustment. It should NOT be used as a permanent solution AND should be monitored and regulated with a Registered Dietitian.

Conclusion

Histamine intolerance is a nuanced condition that highlights the importance of maintaining a balanced diet rich in essential nutrients. While research on DAO and histamine is still emerging, focusing on vitamin B6 as a key cofactor in DAO production provides an actionable step forward in managing intolerance symptoms. If you suspect you may be experiencing histamine intolerance, consulting a registered dietitian can help identify deficits, adjust your diet, and establish a tailored plan for your needs.

Remember, everyone’s body has its own tolerance levels, and it takes a personalized approach to fend off excess histamine effectively. Don’t hesitate to reach out to a professional for guidance!

Resources:

1. Rentzos, G., Weisheit, A., Ekerljung, L., Van Odijk, J., 2024. Measurement of diamine oxidase (DAO) during low-histamine or ordinary diet in patients with histamine intolerance. European Journal of Clinical Nutrition 78, 726–731.. https://doi.org/10.1038/s41430-024-01448-2
2. Low Histamine Diet: Foods to Avoid, Benefits, and Risks
3. https://youtu.be/s_Q5K1cugBI
4. How DAO Enzyme Deficiency Affects Histamine Intolerance and Why Zinc & B6 Matter
5. Vitamin B6: 7 Benefits and How Much You Need
6. Field DT, Cracknell RO, Eastwood JR, Scarfe P, Williams CM, Zheng Y, Tavassoli T. High-dose Vitamin B6 supplementation reduces anxiety and strengthens visual surround suppression. Hum Psychopharmacol. 2022 Nov;37(6):e2852. doi: 10.1002/hup.2852. Epub 2022 Jul 19. PMID: 35851507; PMCID: PMC9787829.
7. Vitamin B6 – Health Professional Fact Sheet
8. Sánchez-Pérez, S., Comas-Basté, O., Veciana-Nogués, M.T., Latorre-Moratalla, M.L., Vidal-Carou, M.C., 2021. Low-Histamine Diets: Is the Exclusion of Foods Justified by Their Histamine Content?. Nutrients 13, 1395.. https://doi.org/10.3390/nu13051395