What's green and brown and grows in the ocean on ropes? Green-lipped mussels (GLM). Most commonly farmed in the waters of New Zealand, they are harvested for culinary treats such as mussels on the half shell, mussel chowder and smoked mussels. In powdered form, they can be packed in capsules and taken as a dietary supplement, which may help inflammatory diseases, including arthritis.

Green-lipped mussels have been a source of food in New Zealand "since the beginning of human habitation," according to the Food and Agriculture Organization of the United Nations. However, the organization says it wasn't until 1971 that the first commercial harvesting of the envy-hued shellfish took place. Today, the United States is one of the largest importers of New Zealand GLM.

The Green-lipped mussels supplements are popular for quieting the symptoms of inflammatory diseases--not only rheumatoid arthritis (RA) and osteoarthritis (OA) but also inflammatory bowel disease (IBD) and asthma. Among the evidence of its benefits:

• Green-lipped mussels helped 76 percent of RA patients and 70 percent of OA patients during a six-month British study reported in a 1998 issue of Complementary Therapies in Medicine. The researchers at the Glasgow Homoeopathic Hospital in England compared a stabilized powder and a lipid extract and concluded that both reduced the pain, swelling and stiffness caused by either type of arthritis.
• A brand of green-lipped mussels lipid extract called Lyprinol improved asthma symptoms in 46 patients after eight weeks, according to Russian research published in the September 2002 issue of the European Respiratory Journal.
• In animals with IBD, Lyprinol reduced disease activity and the weight loss that goes with it, according to the April 2005 issue of the Journal of Gastroenterology.

What's more, a 2003 report in Inflammopharmacology found that combining GLM with anti-inflammatory drags not only increased the drags' benefits but also decreased their risky gastrointestinal side effects. "Because green-lipped mussel is a mainstay of the traditional New Zealand Maori diet, we know that it's a pretty safe medicine," says Michael Whitehouse, PhD, of the University of Queensland in Australia, who co-authored a paper on the benefits of combining GLM with pharmaceutical anti-inflammatories. "It is very suitable for use in combination with other drugs and allows considerable reduction in the use of standard anti-inflammatory agents."

The only known side effects of Green-lipped mussel supplements seem to be fluid retention and nausea. Also, Green-lipped mussel is not recommended for anyone with a shellfish allergy. That said, anyone interested in trying it should look for a stabilized product that has undergone quality-assurance testing, although these things may not be readily obvious.