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  • Writer's pictureKristina David

The Metal Allergy Newsletter: Safe Probiotics

I'm sure many of you have gone down the rabbit hole of trying to find the best probiotic out there to help combat inflammation and heal your gut. I know I did! There are so many different probiotics on the market, it's overwhelming! The problem with probiotics are that many can produce histamine which can be an issue for people with systemic nickel allergy syndrome (SNAS) who have a histamine intolerance. In this month's newsletter I decided to tackle this subject head on. Most supplements are not recommended when you are starting out on the low nickel lifestyle other than Vitamin C and possibly a safe probiotic. Keep reading to learn more and, as always, consult your doctor before starting any new supplements.


Probiotic supplementation in systemic nickel allergy syndrome patients: study of its effects on lactic acid bacteria population and on clinical symptoms (2014)

C.L. Randazzo, A. Pino, L. Ricciardi, C. Romano, D. Comito, E. Arena, S. Saitta and C. Caggia

Probiotics have been proven to help people in different ways such as modulating the immune system, competing against invading microbes and strengthening the epithelial barrier. Several authors have verified L. reuteri's ability to colonize in the gut, modulate the GI immune system, and lower the incidence and duration of GI disturbances. There have also been clinical studies that show ‘an improvement of atopic dermatitis, GI symptoms and intestinal permeability in patients treated with a mixture of L. Reuteri and Lactobacillus rhamnosus strains.’

Up until now there have been no studies on the usefulness of L. reuteri supplements in patients with systemic nickel allergy syndrome (SNAS). Nickel is the most common contact allergen, it's estimated that 17% of women and 3% of men are allergic to nickel. The researchers estimate that 20-30% of people with ACD to nickel experience skin and GI symptoms after eating nickel-containing food. The researchers highlight an epidemiological study where out of 1696 patients on an allergy unit, 98 (5.78%) of them were found to have SNAS. This suggests that SNAS may be an 'emergent allergic condition rather than an occasional finding'. The most common symptoms in people with SNAS were gastrointestinal related, with 87 out of the 98 patients showing signs of GI disturbances. The second most common symptom was the skin, with 51 out of the 98 patients affected. The researchers discuss how patients with SNAS need to follow a low nickel diet, however, this can pose a risk for developing nutritional deficits. They highlight nickel oral hyposensitization as an effective treatment option.

This study was a randomized double-blind -placebo-controlled trial with a control group and an experimental group. 22 women diagnosed with SNAS affecting their skin and GI system were selected. In the end 9 women enrolled in the experimental group and 7 in the control group. They were followed at baseline, 2 weeks after starting L. reuteri supplement and 2 weeks after stopping L. reuteri. Fecal samples and clinical evaluations were performed at each visit. All patients from both groups were asked to follow the low nickel diet. The control group was given a placebo tablet and the experimental group was given 100 million CFU tab of L. reuteri per day.

There was a significant improvement in skin symptoms for both groups after 2 weeks. Most GI symptoms (indigestion, nausea and/or vomiting) were reduced in only the patients treated with L. reuteri, except for recurrent abdominal pains. This symptom improved in both groups. Quality of life improved for both groups as well. The researcher found that in the experimental group, L. reuteri was found in the stool samples which shows it is able to colonize and survive in the GI tract when taken.

In conclusion, the researchers say that their preliminary findings suggest that the low nickel diet is essential to improve the quality life and skin symptom in patients with SNAS; furthermore, supplementing with a probiotics that contain the strain L. reuteri can further help improve GI symptoms. More studies are needed with a longer observation period and larger sample group.


Not everyone with systemic nickel allergy syndrome will have a histamine intolerance but many do. Here is list of strains/species that can be beneficial for people with a histamine intolerance.

  • Bifidobacterium infantis

  • Lactobacillus rhamnosus

  • Bifidobacterium longum

  • Lactobacillus plantarum

  • Lactobacillus reuteri

Although L. reuteri can produce histamine, it also increases cAMP (cyclic AMP) which has anti-inflammatory effects. Check out this research study to learn more.


  • garlic

  • green bananas

  • plantains

  • apples

  • cabbage

  • pomegranate

  • blueberries

  • cranberries

  • radish

  • broccoli

  • carrots

  • artichoke

If you need help managing this allergy, book a free consult with me or check out the Nickel Allergy Course!

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