A recent study has provided important information on diamine oxidase foods and how to raise diamine oxidase naturally through our diet.
The study looked at both macronutrients (protein, fat, and carbohydrates) and micronutrients (including key minerals and vitamins) in healthy women.
The findings suggest that our diet (and not just the histamine content of food) has a profound impact on our histamine degrading enzyme diamine oxidase. Increasing our diamine oxidase may help increase our histamine tolerance.
The study reconfirmed that long-chain fatty acid (such as olive oil) significantly increase diamine oxidase activity.
These findings are consistent with earlier studies including:
A 1998 animal study that found that olive oil increases diamine oxidase in a dose-dependent manner. 
A 2004 human study that found that bile replacement (necessary for fat digestion and absorption) increased levels. 
There was no connection between carbohydrate, proteins, other types of fats, or energy intake and diamine oxidase levels. These findings were also not affected by hormone status.
The study did not find a correlation between fiber intake and diamine oxidase activity, however, the participants had a low soluble fiber intake.
In a previous human study, seven grams per day of galactomannan for 4 weeks increased serum diamine oxidase activity in elderly patients .
The authors, therefore, concluded that they still considered soluble fiber may improve levels.
The study found that magnesium intake is directly related to diamine oxidase activity.
Those findings were also consistent with a rat study that found that a dietary magnesium deficiency decreased levels of activity .
Interestingly, magnesium and calcium levels are also reduced during PMS, and oral administration of magnesium or calcium is known to relieve PMS symptoms [15, 16].
Both copper and zinc are integrally linked to hormone production and a previous animal study found that a dietary copper deficiency or zinc intake decreased blood diamine oxidase activity .
The current study found that copper intake and zinc intake did not alter diamine oxidase activity. These findings suggest key differences between animal and human diamine oxidase mechanisms of action.
Whilst not measured in this study, Vitamin C, has a well-documented history of increasing diamine oxidase, lowering blood histamine levels, and protecting cells from oxidative stress. Adequate Vitamin C is crucial to histamine handling.
The current study reconfirmed that diamine oxidase activity is influenced by the menstrual cycle.
Previous studies have found that diamine oxidase activity is high during pregnancy [2, 8, 9], lower during the luteal phase (when estrogen dominates) , and is known to affect women more than men.
Importantly, however, the current study found that phosphorus, calcium, zinc, magnesium, iron, and vitamin B12, during the luteal phase (days 15 - 28) increased serum diamine oxidase activity.
What if rather than focusing on low histamine foods, or diamine oxidase supplements, we could raise our levels naturally?
This study suggests that by optimizing our overall dietary composition, improving our hormone status (including fat absorption necessary to produce hormones), that our diamine oxidase levels can be increased naturally.
 Miyoshi M, Ueno M, Matsuo M, Hamada Y, Takahashi M, Yamamoto M, Yamamoto I, Mikajiri R, Tabuchi S, Wakida K, Yamanishi M, Hirai M, Usami M, Effect of dietary fatty acid and micronutrient intake/energy ratio on serum diamine oxidase activity in healthy women, Nutrition (2017), doi: 10.1016/j.nut.2017.03.004.
 García-Martín E, Ayuso P, Martinez C, Agúndez JA. Improved analytical sensitivity reveals the occurrence of gender-related variability in diamine oxidase enzyme activity in healthy individuals. Clin Biochem 2007; 40: 1339-41.
 Motoori M, Yano M, Miyata H, Sugimura K, Saito T, Omori T, Fujiwara Y, Miyoshi N, Akita H, Gotoh K, Takahashi H, Kobayashi S, Noura S, Ohue M, Asahara T, Nomoto K, Ishikawa O, Sakon M. Randomized study of the effect of synbiotics during neoadjuvant chemotherapy on adverse events in esophageal cancer patients. Clin Nutr 2015.
 Ji Y, Sakata Y, Li X, Zhang C, Yang Q, Xu M, Wollin A, Langhans W, Tso P. Lymphatic diamine oxidase secretion stimulated by fat absorption is linked with histamine release. Am J Physiol Gastrointest Liver Physiol 2013; 304: G732-G740.
 Feillet-Coudray C, Coudray C, Bayle D, Rock E, Rayssiguier Y, Mazur A. Response of diamine oxidase and other plasma copper biomarkers to various dietary copper intakes in the rat and evaluation of copper absorption with a stable isotope. Br J Nutr 2000; 83: 561-8.
 Han XY, Ma YF, Lv MY, Wu ZP, Qian LC. Chitosan-zinc chelate improves intestinal structure and mucosal function and decreases apoptosis in ileal mucosal epithelial cells in weaned pigs. Br J Nutr 2014; 111: 1405-11.
 Hamada Y, Shinohara Y, Yano M, Yamamoto M, Yoshio M, Satake K, Toda A, Hirai M, Usami M. Effect of the menstrual cycle on serum diamine oxidase levels in healthy women. Clin Biochem 2013; 46: 99-102.
 Kamiya S, Nagino M, Kanazawa H, Komatsu S, Mayumi T, Takagi K, Asahara T, Nomoto K, Tanaka R, Nimura Y. The value of bile replacement during external biliary drainage: an analysis of intestinal permeability, integrity, and microflora. Ann Surg 2004; 239:510-7.
 Thys-Jacobs S, Starkey P, Bernstein D, Tian J. Calcium carbonate and the premenstrual syndrome: Effects on premenstrual and menstrual symptoms. Premenstrual syndrome study group. Am J Obstet Gynecol 1998; 179: 444-52.
 Nakao M, Ogura Y, Satake S, Ito I, Iguchi A, Takagi K, Nabeshima T. Usefulness of soluble dietary fiber for the treatment of diarrhea during enteral nutrition in elderly patients. Nutrition 2002; 18: 35-9.