Belly fat, or visceral adipose tissue (VAT), is the fat that accumulates around the organs in the abdomen. It is strongly related to metabolic disorders including insulin resistance, fatty liver and inflammation. Because of the close proximity of belly fat to the intestines, and the ability of gut bacterial toxins to affect inflammation outside the gut, the relationship of increased intestinal permeability, or leaky gut, to increased abdominal fat has been investigated.

Indeed, previous studies in animals and in people with illnesses like Crohn’s disease1 and non-alcoholic fatty liver disease (NAFLD), have found a link between leaky gut and belly fat. Until recently, however, no studies had been done in healthy humans. Now the picture is all coming together nicely, as a new study highlights.

In 55 healthy women, intestinal permeability was estimated by measuring urinary excretion of ingested nonmetabolizable sucralose and mannitol. (They measure the ratio of excreted sucralose to mannitol—if the sucralose level is high, it means it leaked through the gut, even though it shouldn’t.) Further, imaging was performed of subcutaneous fat (fat just under the skin) visceral fat, and liver fat. The researchers found that increased leaky gut was associated with increases in both visceral fat and liver fat content in healthy women.2 This is important because previous studies have found this in people with illnesses, but it was not known if leaky gut could was associated with belly fat in healthy individuals. Now we have a better picture of this gut connection.

The women in the study had no history of gut disorders, yet some of them still had leaky gut, and those with the worst leaky gut also had the most belly and liver fat. The researchers stated, “The current findings suggest that even without pathologically compromised gut function, intestinal permeability still appears to play a role in visceral adipose and liver fat accumulation.” Importantly, they go on to mention the role that the gut microbiota plays in this picture. Alterations in gut bacteria composition has been associated with metabolic dysfunction,3 and gut bacteria help regulate gut barrier function,4 they mention.

They conclude, “Our data suggests that intestinal permeability may be an important part of the link between diet, gut microbial balance, inflammation, and metabolic disorders. The present findings are consistent with the emerging role of gut in metabolic health.”

Abdominal fat has even been considered an organ of its own, due to the many chemicals and hormones it produces, just as organs do. The role of VAT as a contributor to metabolic diseases is possibly the most important factor to consider when trying to reduce disease risk. That the accumulation of this belly fat is related to the gut, and might even originate in the gut, takes our search into the prevention of diseases yet one more step closer to the source. A healthy gut is truly the foundation of total body health.


  1. Desreumaux P, et al., “Inflammatory alterations in mesenteric adipose tissue in Crohn’s disease.” Gastroenterology. 1999 Jul;117(1):73-81.
  2. Gummesson A, et al., “Intestinal Permeability Is Associated With Visceral Adiposity in Healthy Women.” Obesity (Silver Spring). 2011 Aug 18. [Epub ahead of print]
  3. Cani PD and Delzenne NM, “The role of the gut microbiota in energy metabolism and metabolic disease.” Curr Pharm Des. 2009;15(13):1546-58.
  4. Sharma R, et al., “Molecular modulation of intestinal epithelial barrier: contribution of microbiota.” J Biomed Biotechnol. 2010;2010:305879.