Quick answer: Cellular Rebuilding is the final phase of the Leaky Gut Protocol. The gut lining renews itself quickly, and this phase supports that process with nutrients such as glutamine, zinc, omega-3s and collagen-rich foods, anti-inflammatory foods, soothing herbs used with guidance, and plenty of sleep and stress care.
Key takeaways
The gut lining has a remarkable ability to renew itself, and phase four supplies the nutrients it needs.
Glutamine, zinc, omega-3s and collagen are among the nutrients linked with gut repair, and soothing herbs are sometimes used.
Regular sleep and daily stress care support the lining’s renewal, while ongoing stress can increase permeability.
The goal of Phase 4
The intestinal lining has a remarkable ability to renew itself. This phase supplies what it needs. Overview: the four-phase approach.
Step 1: Nutrients for gut repair
- Glutamine: a key fuel for small-intestine cells
- Zinc: supports tight junctions and wound healing
- Omega-3 fatty acids: calm inflammation
- Collagen and gelatin: found in bone broth
- Food first; discuss supplements and doses with your provider (see nutrient deficiencies)
Step 2: Anti-inflammatory foods
Fatty fish, turmeric, ginger, leafy greens and berries.
Step 3: Soothing herbs
Soothing herbs include aloe vera, deglycyrrhizinated licorice (DGL), marshmallow root and slippery elm. Herbs can interact with medications, so check with your provider, especially if you are pregnant.
Step 4: Sleep
Keep a regular sleep schedule, create a relaxing bedtime routine, and keep your bedroom cool, dark and quiet. Avoid caffeine, nicotine and alcohol near bedtime, and limit screens before bed.
Exercise regularly, but not right before bed, and avoid heavy late-night meals.
Step 5: Manage stress
Try a few minutes of meditation or slow belly breathing daily: sit comfortably, breathe in slowly through your nose so your belly rises, and breathe out slowly. See breathwork.
Gut renewal and healthy aging
The gut lining is rebuilt from stem cells every few days. Sleep, nutrition and lower stress support that renewal, while stress can increase gut permeability and poor sleep may slow repair.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have ongoing bloating, gas, diarrhea or constipation, or food reactions that seem to be multiplying. The same is true if you have fatigue, skin flares or joint aches alongside gut symptoms, or if you want a personalized gut plan instead of guessing.
See a medical provider promptly for blood in your stool, black stools, unexplained weight loss, persistent vomiting, severe abdominal pain, fever, or trouble swallowing.
What the research shows
Glutamine is one of the best-studied nutrients for the gut lining. In a 2019 randomized, double-blind trial by Zhou and colleagues, adults with diarrhea-predominant IBS and increased permeability after a gut infection took 5 g of glutamine three times a day or a placebo for 8 weeks (54 and 52 finished each group). 79.6% of the glutamine group had a meaningful drop in symptom scores compared with 5.8% on placebo, and urine permeability testing returned to normal only in the glutamine group. It was a single trial in a specific group, so the results may not apply to everyone.
Bovine colostrum has also been tested. A 2024 meta-analysis by Hajihashemi and colleagues of 10 randomized trials in athletes and patients found that colostrum lowered urine-based measures of intestinal permeability but did not change I-FABP, a blood marker of gut-lining injury. The included trials differed a lot in dose and length, and the authors called for more research.
Want help finding the root of your gut symptoms?
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Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Which nutrients or soothing herbs would be safe for me, given my medications?
Which nutrients matter most for repairing my gut lining?
How long does this rebuilding phase usually take?
Which signs would tell us my gut lining is getting stronger?
Frequently asked questions
How long does it take to repair the gut lining?
The lining renews within days, but recovery from long-standing issues takes longer and varies.
Does bone broth help leaky gut?
It provides collagen and gelatin; it can be a supportive food.
Is glutamine safe?
Generally well tolerated; discuss dose with your provider.
Why does sleep matter for gut repair?
Much of the body’s repair happens during sleep.
Sources
- Zhou Q, Verne ML, Fields JZ, et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut 2019. PMID: 30108163. https://pubmed.ncbi.nlm.nih.gov/30108163/
- Hajihashemi P, Haghighatdoost F, Kassaian N, et al. Bovine Colostrum in Increased Intestinal Permeability in Healthy Athletes and Patients: A Meta-Analysis of Randomized Clinical Trials. Dig Dis Sci 2024. PMID: 38361147. https://pubmed.ncbi.nlm.nih.gov/38361147/
- Kim MH, Kim H. The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases. Int J Mol Sci 2017. PMID: 28498331. https://pmc.ncbi.nlm.nih.gov/articles/PMC5454963/
- Skrovanek S, et al. Zinc and gastrointestinal disease. World J Gastrointest Pathophysiol 2014. PMID: 25400994. https://pmc.ncbi.nlm.nih.gov/articles/PMC4231515/
- Calder PC. Omega-3 fatty acids and inflammatory processes: from molecules to man. Biochem Soc Trans 2017. PMID: 28900017. https://pubmed.ncbi.nlm.nih.gov/28900017/
- Barker N. Adult intestinal stem cells: critical drivers of epithelial homeostasis and regeneration. Nat Rev Mol Cell Biol 2014. PMID: 24326621. https://pubmed.ncbi.nlm.nih.gov/24326621/
- Vanuytsel T, et al. Psychological stress and corticotropin-releasing hormone increase intestinal permeability in humans by a mast cell-dependent mechanism. Gut 2014. PMID: 24153250. https://pubmed.ncbi.nlm.nih.gov/24153250/
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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