Some supplements have been shown to improve the gut barrier. Acacia gum is by far the most important one. Also, you could also try zinc OR glutamine. If you are already taking zinc (as part of the supplement recommendations for everyone with acne), then you are already covered. I don’t think there’s any need to take both zinc and glutamine.

Acacia gum

Acacia gum is a complex fiber that’s indigestible to humans. It reaches the colon practically untouched where it can feed the probiotic bacteria. Research shows it supports Bifidobacterium and increases the production of butyrate and other beneficial short-chain fatty acids in the colon. Taking acacia gum is one of the best ways to support healthy bacteria in the colon.

A study from 2003 showed that acacia gum ferments at much slower speeds than many other prebiotics. As such, it’s better tolerated than most other fibers or prebiotics. The acacia dosage was ramped up from 10 g/day to 70 g/day. At doses below 30 g/day, acacia didn’t produce any more side effects than a neutral sugar solution used as a control. At 60 g/day only 3 out of the 20 participants had any digestive side effects, and even then the side effects were very mild.

The study also showed a significant increase in the number of Bifidobacterium in people taking acacia gum.

Dosage

A 2008 study tested various doses ranging from 5 to 40 g/day and determined 10 g/day as the optimal dose. Higher doses didn’t support further growth of Bifidobacterium and in fact reduced the number of Lactobacilli, another probiotic bacteria.

I recommend that you start slowly and build up the dosage over 2 to 3 weeks. This gives your gut time to adjust and should further minimize any digestive problems.

For references:

• 1 level teaspoon = 2 grams of acacia gum
• 1 level tablespoon = 6 grams of acacia gum

Glutamine

Glutamine is an amino acid and an important fuel and protein source for intestinal cells. Glutamine supports the integrity of the intestinal barrier in the face of intestinal damage.

A study from 2012 showed that supplementing with either glutamine or whey protein normalized intestinal permeability in 57% of the inflammatory bowel disease patients. Glutamine has also been shown to prevent intestinal barrier damage from chemotherapy drugs. A recently published study showed that glutamine supplementation prevents an increase in intestinal permeability following intense exercise. Other studies have shown similar results.

Dose: 5g, twice a day

It’s likely that you can also get the same benefits by supplementing with whey protein, which is a good source of all amino acids. Manufacturers often add amino acids (glutamine included) into the mix, further increasing the glutamine done.

Though people with hormonal-type acne should be careful. Whey protein increases insulin levels, which in turn triggers androgen release from adrenals.

Zinc

Zinc plays an important role in intestinal structure and function. Even relatively mild zinc deficiencies can damage the intestinal barrier and lead to intestinal permeability – especially when the gut is under stress. Similarly, zinc supplementation can protect the intestinal barrier when the is stressed.

One study showed that zinc protects intestinal cells exposed to TNF-a. TNF-a is a signaling protein that’s released when cells are attacked or injured. Think of it as an alarm signal that brings the immune system killer cells into the area. Intestinal cells without sufficient zinc die when exposed to TNF-a.

Animal studies have shown that even relatively mild zinc depletion increases the intestinal barrier damage from other stressors, such as alcohol.

Although it is known that zinc is necessary for proper liver function, increasing evidence suggests that zinc plays an important role in maintaining epithelial integrity of the gastrointestinal tract.

Zhong, W., McClain, C. J., Cave, M., Kang, Y. J. & Zhou, Z. The role of zinc deficiency in alcohol-induced intestinal barrier dysfunction. Am. J. Physiol. Gastrointest. Liver Physiol. 298, G625–33 (2010). https://www.ncbi.nlm.nih.gov/pubmed/20167873

Unfortunately, there haven’t been many relevant studies that investigate zinc’s effect on intestinal permeability. A few have been done on malnourished or ill patients. And while those studies showed zinc protects and repairs the intestinal barrier, it’s not clear that it will also help otherwise healthy people who struggle with gut issues. In the most relevant study, zinc supplementation prevented intestinal barrier damage caused by indomethacin (a painkiller) – as compared to 3 to 4 fold increase in intestinal permeability in the placebo group.

Dose: 35 to 40 mg/day

Plant polyphenols (PP)

Polyphenols are antioxidants found in plant foods. Preliminary evidence shows they might be beneficial to the intestinal barrier and overall gut health.

For example, colonic metabolites of tea PPs inhibit the growth of pathogenic bacteria much more strongly than that of commensal bacteria.

Amasheh, M., Andres, S., Amasheh, S., Fromm, M. & Schulzke, J.-D. D. Barrier effects of nutritional factors. Ann. N. Y. Acad. Sci. 1165, 267–73 (2009). https://www.ncbi.nlm.nih.gov/pubmed/19538315

I don’t recommend supplementing with polyphenols. I included them here to highlight the importance of a healthy and varied diet in gut health. Polyphenols are found in:

• Fruits
• Vegetables
• Tea (especially green and rooibos teas)
• Coffee

Dose: As much as you like