Slippery Elm Bark
Slippery elm (Ulmus rubra) is a type of elm tree native to eastern North America from southern Quebec to northern Florida and east to Texas. The inner bark has long been used in traditional Native American medicine to treat wounds and gastrointestinal ailments. Slippery elm is also a main ingredient in essiac tea.
Slippery elm contains a type of soluble fiber known as mucilage. Mucilage traps and absorbs water, forming a gel-like substance that can coat mucous membranes, providing short-term relief of pain and inflammation The high calcium content may also act as a mild antacid.
Slippery elm is also known as red elm, gray elm, soft elm, moose elm, and Indian elm. It should not be confused the American elm (U. americana), the species of which it resembles but has no medicinal properties.
Health Benefits
Slippery elm has long been used in folk medicine. It is either taken orally or applied topically to aid in the healing of cuts and burns. Among some of the conditions slippery elm is believed to treat are:
Acid reflux
Inflammatory bowel disease (IBD)
Irritable bowel syndrome (IBS)
Constipation
Mouth ulcers
Sore throat
Weight loss
Some proponents claim that slippery elm can treat upper respiratory tract infections, syphilis, herpes, gout, psoriasis, and even breast or lung cancer. To date, there is no clinical evidence to support these claims.1
Weight Loss
There are some who insist that slippery elm can promote weight loss by suppressing the appetite and "detoxing" the bowel. The presumption is that the production of mucilage can increase the volume of your stomach contents, filling you up faster. The mucilaginous bulk is then believed to "trap" dietary fats and speed bowel clearance. The hypothesis is yet to be proven.
A 2018 study in the Journal of Dietary Supplements found that women provided a four-week course of a slippery elm supplement experienced no differences in body composition or waist size compared to those given a placebo.
Despite this, there are some who consume slippery elm powder as a porridge-like gruel to "amplify" these effects. Not only is there no evidence that this works, but it is also unknown how safe the practice is.
Sore Throat
Slippery elm has been used to make commercial medicines as far back as the 1840s when a physician named Henry Thacker starting producing herbal remedies for sale to doctors. Among them was a slippery elm elixir that was first sold as an oral suspension and later as lozenges. As a natural demulcent, slippery elm can reduce inflammation by coating lining of the throat and esophagus.1
Thacker's Slippery Elm Lozenges are still produced today, in addition to a slippery elm lip balm used to treat chapped lips. Other manufacturers have since joined in, producing slippery extracts, tinctures, lotions, and herbal teas.
In the 1960s, the U.S. Food and Drug Administration classified slippery elm as a botanical drug, believing it safe for the treatment of minor sore throat pain.
However, the agency fell short of declaring it effective, characterizing slippery elm as "a demulcent with limited clinical effects."
While slippery elm is believed by some to relieve the symptoms of acid reflux, the drug action is relatively short-lasting (around 30 minutes) and does nothing to treat the underlying causes of reflux.
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Digestive Disorders
Proponents of slippery elm claim that it can alleviate many of the symptoms of inflammatory bowel diseases (such as ulcerative colitis) by forming a temporary protective barrier in the intestines. To date, the evidence of this is mixed.
A 2002 study from England found that slippery elm exerted antioxidant effects on colon tissue samples taken from people with ulcerative colitis. What the test tube study did not show is whether the same effect would occur if a slippery elm was taken orally.
Meanwhile, other scientists have looked into whether slippery elm can control the symptoms of irritable bowel syndrome (IBS), classified either as constipation-predominant IBS (IBS-C) or diarrhea-predominant IBS (IBS-D).
A 2008 study from Australia reported that two different herbal supplements containing slippery elm were able to increase bowel frequency by 20 percent in people with IBS-C but had minimal effect in people with IBS-D.
Both groups were also said to experience improvements is straining, abdominal pain, and bloating. Despite the positive findings, the conclusions were limited by the fact that the research was conducted by a commercial herbal drug manufacturer.