Moreover, people who took the oral supplement were less likely to start corticosteroid drug therapy, which has many long-term side effects.
"Our study proves that an oral supplement which combines fish oil, soluble fibre and antioxidants is safer and causes fewer side effects than many of the medications currently available to treat ulcerative colitis," said Dr Douglas Seidner, lead author of the study.
Researchers at The Cleveland Clinic in the US conducted a randomized controlled, clinical trial of patients aged 18 and older with mild to moderate active ulcerative colitis.
Patients on corticosteroid therapy who were given the oral supplement had a significant reduction in the dose of corticosteroids needed to control their condition compared to a placebo group, write the researchers in the journal Clinical Gastroenterology and Hepatology.
The oral supplement is manufactured by Ross Products and Abbott Laboratories and is currently being evaluated for commercial introduction.
Ulcerative colitis is one of the UK's most common forms of inflammatory bowel disease and affects an estimated 50,000 people in the UK, with a particularly high incidence in north-east Scotland. The acute and chronic disease causes inflammation and sores, called ulcers, in the lining of the large bowel.
Treatments for the disease, including corticosteroids and mesalamine are intended to control inflammation. While corticosteroids are highly effective in the treatment of ulcerative colitis, prolonged use often leads to insomnia, mood alterations, increased appetite, hypertension, osteoporosis and other adverse events.
These adverse effects lead to discontinuation of the therapy by many patients. However, more than 25 per cent of patients who discontinue the therapy have a relapse of symptoms.
Previous smaller studies have shown that fish oil is effective in reducing the need for corticosteroids in ulcerative colitis patients. The current study combines fish oil with soluble fibre to diminish the inflammation associated with ulcerative colitis symptoms.
"The need to find new treatments that are safe, effective and inexpensive remains, and physicians should consider adding this combination of active ingredients as an adjuvant therapy for ulcerative colitis," concluded Seidner.