The Secret Shield Within
He used to think of immunity as something that happened in the blood - T-cells, antibodies, inflammation. But the more he read, the more it became clear: the real front line is the mucosa, especially in the gut. And the secret soldier guarding that border? A molecule called secretory IgA.
Produced by plasma cells in the gut lining, secretory IgA (sIgA) coats microbes, food particles, and foreign molecules, helping the immune system tolerate the good and tag the bad - without causing full-blown inflammation. It’s the immune system’s whisper, not its scream.
He suspected his own mucosal barrier had been worn down. Decades of stress, occasional overtraining, NSAIDs, sleep disruption. His gut lining had likely thinned, his microbial diversity lowered. And that meant lower sIgA - and higher vulnerability to inflammation, food sensitivities, even autoimmune drift.
So he set out to restore it.
He increased his intake of immunonutrients: zinc, natural sources and precursors of vitamins A and D. He gave some thoughts about colostrum, too. He ate more fermented vegetables, especially those high in Lactobacillus plantarum, known to support mucosal immunity. And he slowed down. Meals became mindful. Breathing became ritual. He even began chewing 20 times per bite - less for digestion, more to signal calm.
Within weeks, something softened. His gut stopped reacting to formerly “safe” foods. His sinuses opened. His skin cleared. He suspected his tolerance had returned - not just in his gut, but in his life.
He didn’t need more immunity. He needed better communication between body and microbe. Between inside and outside. That, he realized, was the essence of health.
Next week: “My Gut and I Went to Therapy” - stress, cortisol, and the microbiome-brain feedback loop.