17 August, 2011
L-Glutamine and Ulcerative Colitis
Ulcerative colitis, a chronic, recurrent condition that causes inflammation of your colon and rectum, affects between 250,000 and 500,000 people in the United States. Treatment usually involves long-term use of aspirin-like medications, immune-modulating agents and corticosteroid drugs, such as prednisone. However, the side effects of such drugs may have you wondering if nutritional therapies could offer some benefit for this disease. Although L-glutamine has shown promise in animal studies, its benefits for ulcerative colitis in humans are less clear. Ask your doctor if L-glutamine is appropriate for you.
The cells lining your gastrointestinal tract – called enterocytes – are metabolically very active, and they normally undergo rapid division and replacement. According to a review in the March 2010 issue of “Inflammatory Bowel Diseases,” L-glutamine is an important source of fuel for enterocytes in your small intestine, but the cells lining your colon may prefer different compounds. Research shows that L-glutamine supports intestinal function in patients suffering from trauma and serious infections, and that glutamine induces new cell growth in animal models of ulcerative colitis. However, studies on humans with ulcerative colitis have not consistently demonstrated the same benefit.
If you are healthy, enterocytes form a continuous mucosal barrier along the interior of your intestine. Adjacent enterocytes are bound together by “tight junctions” that are formed by interlocking proteins arranged around the perimeter of each cell. Tight junctions are disrupted by inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease, thereby permitting the loss of fluids and electrolytes and the passage of bacteria and potentially toxic substances into your bloodstream. A study published in the June 1996 issue of “Gut” demonstrated that the mucosal barrier of inflamed rat colons could be restored by glutamine treatment.
Ulcerative colitis affects only your colon and rectum – that is, your lower intestines. Oral doses of L-glutamine are rapidly and efficiently absorbed by the cells lining your small intestine – the upper part of your gastrointestinal tract – making it unlikely that L-glutamine could reach your colon in effective concentrations. Furthermore, unlike enterocytes in your small intestine, which avidly use L-glutamine as an energy source, the cells lining your colon prefer a short-chain fatty acid called n-butyrate as a source of fuel.
Research shows that L-glutamine speeds the replacement of injured colonic cells in animal models of ulcerative colitis. Although the effect has not been demonstrated in humans, L-glutamine might help to reestablish the integrity of intestinal tight junctions and reduce the “leakiness” of your colon during episodes of ulcerative colitis. However, L-glutamine is rapidly absorbed by the cells of your upper intestinal tract before it can reach your colon in appreciable amounts, and it may not be your colon’s preferred source of energy in any event. Human studies have not shown consistent benefit from L-glutamine supplementation in patients with ulcerative colitis. Your physician can help you decide if L-glutamine supplementation could be beneficial for you.
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