Histamine intolerance, oxalates & lectins
This blog post discusses the connection between oxalates, lectins, and histamine intolerance. Intolerance to these two substances can also occur, potentially leading to symptoms in addition to histamine intolerance.
Oxalates/oxalic acid
Oxalic acid, in the form of oxalates, is found primarily in plant-based foods. These include mainly fruits, vegetables, legumes, nuts, seeds, and dried spices and herbs.
4 Facts About Oxalates in the Context of Histamine Intolerance
1. Most foods high in oxalate also have a high histamine content or are histamine liberators.
2. Oxalates can promote inflammation when there is an imbalance in the gut. Inflammation in the body, in turn, promotes the release of histamine, creating a vicious cycle.
3. If a leaky gut (permeable intestinal lining) exists, oxalates (just like histamine) can spread throughout the body and cause discomfort.
4. In many cases, the cause of oxalate intolerance is an imbalanced gut (more information follows below).
If you suspect you are intolerant to oxalates, an elimination diet is a good option, in which you initially only avoid foods that have a very high oxalic acid content.

Oxalate-rich foods
- Almonds (1)
- Wild herbs
- Beetroot
- Sweet potatoes
- Sesame (1)
- Rhubarb (1)
- Chard (1)
- Spinach (2)
- Starfruit
- Cocoa (2)
- Fig (1)
- Tomato (2)
- Pulses (beans, lentils, peas) (2)
- Wheat (1) & Rye (1)
Furthermore, it is produced naturally through metabolism within the body. Oxalates are the end products of ascorbate, glyoxylate, and glycine metabolism in the human body and are primarily formed through the breakdown of amino acids and ascorbic acid. Oxalates do not pose a problem for a healthy gut.
However, if dysbiosis (imbalance of the gut flora), leaky gut (increased intestinal permeability), SIBO (small intestinal bacterial overgrowth), or inflammation in the intestine is present, oxalates can often be insufficiently broken down because the necessary bacterial strains are reduced or absent. A deficiency in vitamins B6, B1, and magnesium can also lead to elevated oxalate levels.
Lectins and histamine intolerance
Lectin intolerance or lectin poisoning can coexist with histamine intolerance and often occurs when the intestine is in a dysbiosis or when there is a leaky gut (permeable intestinal mucosa).
Lectins are carbohydrate-binding proteins found in plants that protect them from predators by causing poisoning symptoms after ingestion. For this reason, animals tend to avoid plants containing lectins.
Lectins cannot harm us humans as long as our metabolism is balanced and our intestines are healthy, since the intestinal barrier is normally strong enough to prevent the insufficiently digested molecules from passing through the intestinal mucosa into the bloodstream.
However, if there is an imbalance in the gut flora, the intestinal lining is often more permeable or even leaky, which allows not only histamine to spread throughout the body, but also undigested lectin molecules. If this occurs, lectins can cause the following symptoms:
- nausea
- Vomit
- Flatulence
- Feeling of fullness
- heartburn
- Diarrhea

Since the symptoms are once again identical to those of histamine intolerance (HIT), it is important to keep a food and symptom diary and avoid the following foods for a period of 4-6 weeks:
e.g. chickpeas, beans, lentils, peanuts
e.g. wheat(1), rice, maize
e.g. flaxseed, sesame (1) or pumpkin seeds
Sources
- Charrier, Marina JS; Savage, Geoffrey P; Vanhanen, Leo; Oxalate content and calcium binding capacity of tea and herbal teas, Asia Pac J Clin Nutr, 11(4), 2002, pp. 298-301.
- Burgerstein, Lothar, Handbook of Nutrients, 12th ed., pp. 570f.
- Hoenow, Ruth; Gu, Ke-Liang Reinhold; Hesse, Albrecht; Siener, Roswitha, Oxalate content of green tea of different origin, quality, preparation and time of harvest, Urological Research, Volume 38 (5), Springer Journals, Oct 1, 2010, pp. 377-381.
- Weiss, Claudia; Oxalic acid, Ernährungs-Umschau, 11/2009, pp. 636-639.
- Noonan, SC., Savage, GP, Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition, 8(1), 1999, pp. 64-74.
- Regarding the bacterial strain: https://pubmed.ncbi.nlm.nih.gov/11532105/
Lectins :
- Vojdani, A., 2015. Lectins, agglutinins, and their roles in autoimmune reactivities. Alternative Therapies , 2 , p. 142. Accessed online on July 6, 2018 at: http://bant.org.uk/wp-content/uploads/2015/11/Alternative%20_Therapies_Special_Issue_Deluxe.pdf#page=44
- Vasconcelos, IM and Oliveira, JTA, 2004. Antinutritional properties of plant lectins. Toxicon , 44 (4), pp. 385–403. Retrieved online on July 6, 2018, from: https://www.sciencedirect.com/science/article/pii/S0041010104001916
- Xie, W., Adolf, J. and Melzig, MF, 2017. Identification of Viscum album L. miRNAs and prediction of their medicinal values. PloS one , 12 (11), p.e0187776. Accessed online on July 7, 2018 at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187776
- Orange, M., Reuter, U. and Hobohm, U., 2016. Coley's lessons remembered: augmenting mistletoe therapy. Integrative cancer therapies , 15 (4), pp.502-511. Accessed online on July 7, 2018 at: http://journals.sagepub.com/doi/10.1177/1534735416649916
