Irritable Bowel Syndrome (IBS)

probiotics—Historical trials reported strain 35624 as “B. infantis,” but genome analysis assigns 35624 to B. longum subsp. longum; its results do not support the infantis subspecies generally

Nickel ACM prevalence: 30-65% of IBS patients in European studies test positive for nickel sensitization

90.3% positivity in endometriosis patients with GI symptoms tested for Ni ACM via oral mucosa patch test

Low-nickel diet response: Dramatic improvement in all GI, extra-intestinal, and even gynecological symptoms in nickel-sensitized patients

Nickel exposure in occupational workers increases Escherichia-Shigella and decreases Lactobacillus, Lachnospiraceae, Blautia

Dietary nickel is the primary trigger for SNAS symptoms. High-nickel foods overlap significantly with high-FODMAP foods: legumes, whole wheat, onions, garlic, and nuts are high in both FODMAP compounds and nickel

Cadmium from tobacco compounds metal-driven dysbiosis in IBS patients who smoke

Heavy metals disrupt tight junction proteins (claudin, occludin, ZO-1) via multiple mechanisms, compounding the barrier dysfunction already present in IBS

ruminococcus and dorea—Enriched in IBS; associated with altered fermentation patterns and gas production contributing to bloating.

escherichia coli—May expand in the setting of nickel-driven dysbiosis and SIBO. Nickel exposure increases Escherichia-Shigella abundance.

lactobacillus—Depleted in IBS. Nickel exposure specifically reduces Lactobacillus abundance. L. rhamnosus GG has the best evidence for IBS symptom relief.

bifidobacterium—Depleted in IBS. Clinical studies historically labeled strain 35624 as “B. infantis,” but comparative genomics assigns 35624 to B. longum subsp. longum; those findings are strain-specific and are not evidence for B. longum subsp. infantis.

TLR4 activation by nickel—Nickel activates TLR4 on mucosal immune cells, triggering innate immune responses and mast cell degranulation in sensitized individuals. This is a direct metal-immune interface that does not require microbial involvement.

Nickel allergic contact mucositis (ACM)—In sensitized individuals (30-65% of IBS patients), dietary nickel triggers type IV hypersensitivity in the intestinal mucosa. Mucosal biopsies show increased eosinophils and mast cells at sites of nickel contact. This allergic inflammation is the primary ecological driver, not infection or autoimmunity.

Fermentative dysbiosis—64.71% of SNAS patients have fermentative dysbiosis (elevated urinary indican, indicating small intestinal disruption), 3.92% putrefactive, and 31.37% mixed. This suggests the small bowel microbiota is primarily perturbed.

Diet + probiotics synergy—Low-nickel diet combined with targeted probiotics achieves eubiosis in 72.73% of SNAS patients vs. 41.38% with diet alone (p=0.026), but benefits are maintained only 4-6 weeks after treatment cessation.

endometriosis (overlap score: 0.55)—Highest overlap. Shared nickel sensitivity (90.3% Ni ACM positivity in endometriosis patients with GI symptoms), shared estrogen connections via estrobolome, and shared mast cell activation. Low-nickel diet improves both GI and gynecological symptoms in endometriosis.

Probiotic durability—Benefits of low-nickel diet + probiotics last only 4-6 weeks post-treatment. What maintains the dysbiotic state, and can longer interventions achieve durable remission?

Primitive 1: Metals as Selective Pressures—Dietary nickel selects for nickel-tolerant taxa (Escherichia-Shigella) while suppressing nickel-sensitive taxa (Lactobacillus, Lachnospiraceae, Blautia). This metal-driven microbial selection produces the IBS dysbiosis pattern in sensitized individuals.

Primitive 5: Two-Sided Ecological Engineering—Low-nickel diet + targeted probiotics achieves eubiosis in 72.73% vs. 41.38% with diet alone. The intervention suppresses the allergic trigger (nickel) while restoring beneficial taxa (Lactobacillus, Bifidobacterium).