Table 4.

Examples from the literature of in vivo human studies showing alterations in intestinal permeability as a result of gut-directed therapy with nutrient, supplement or fiber

Therapy	Patients with	Comments	Reference #
Glutamine i.v.	Nutritional depletion pre-surgery	Patients with increased intestinal permeability did not improve after glutamine-enriched total parenteral nutrition	122
Enteral glutamine	50–80% burns	Urinary LMR in enteral glutamine group lower than standard enteral formula	123
Enteral glutamine	30–75% burns	Plasma DAO activity and urinary LMR in enteral glutamine group were lower than in untreated burn group	124
Enteral glutamine	Crohn’s disease patients	Glutamine and active control (whey) both reduced LMR	125
Oral glutamine	Post-infectious IBS	Elevated urinary LMR was normalised in the glutamine but not the control group	65
Galactooligo-saccharides	Obesity	Post-aspirin sucralose:lactulose ratios and sucralose excretion reduced indicating improvements in colonic permeability	79
Inulin- enriched pasta	Healthy young volunteers	Reduced serum zonulin and urine LMR but not mannitol excretion	126
Psyllium	Children with IBS	No effect on sucrose and sucralose recovery, and LMR	127
Fiber	NAFLD patients undergoing diet Rx for obesity	Increasing nutritional fiber from 19 to 29g/day reduced serum ZO levels, and improved hepatic steatosis	128
Rhubarb	Day 3 post-burns	Plasma DAO activity in rhubarb-treated group were lower than in controls	129
Gelling complex of tara gum + exopoly- saccharides of Strep. Thermos-philus ST10	Healthy participants	Reduced LMR and redcued sucralose concentration suggesting improvement in both small intestinal and colonic permeability	130
Ascorbic acid	Healthy female participants	Excretion of lactulose over 6-hr augmented after consumption of either aspirin or ascorbic acid compared with that after consumption of placebo	131
Fermented and amylase-digested weaning foods	Tanzanian children aged 6–25 months with acute diarrhea	Reduction in L/M ratio between admission and day 3 of hospitalization was significantly greater in the fermented and amylase-digested weaning group (89%) than the conventional or high-energy density amylase digested porridge groups (44% and 75%, respectively)	132
Common beans	Rural children in second year of life (Malawi)	Additional beans in diet reduced lactulose excretion without effect on LMR	133
Micronutrient-fortified complementary/replacement food	Zambian infants from 6 to 18 months old	LMR (adjusted for baseline urinary L:M ratio, socio-economic status, mother’s education, season of birth and baseline stunting, and stratified by maternal antenatal HIV status, child’s sex, concurrent breast-feeding status and anemia at baseline) worse in group with fortified diet especially among boys and, among the infants of HIV-negative mothers	134

DAO=diamine oxidase; LMR=lactulose mannitol excretion ratio