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DDW: Fatty Acids May Protect Against Ulcerative Colitis
  MedPage Today
Published: May 04, 2010
NEW ORLEANS -- Getting more oleic acids -- from olive or peanut oils, for instance -- may prevent against development of ulcerative colitis, researchers said here.
Patients in a prospective cohort study who had the highest intake of the monounsaturated omega-9 fatty acid had almost a 90% reduced risk of the disease, Andrew Hart, MD, of the University of East Anglia in Norwich, England, and colleagues reported during Digestive Disease Week here.
Oleic acids "may dampen inflammation in the bowel," Hart said. "They could do that by blocking chemicals that stimulate inflammation."
He said the causes of ulcerative colitis are largely unknown, but it's possible that dietary mechanisms may be involved -- particularly fatty acids.
Action Points
- Explain that data from a prospective study show that higher intake of oleic acid -- an omega-9 fatty acid -- may protect against the development of ulcerative colitis.
- Point out that while the study can document associations, it cannot prove causality.
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered preliminary until published in a peer-reviewed journal.
Omega-9 fatty acids, for example, may inhibit the formation of pro-inflammatory metabolites that are found in high concentrations in the mucosa of patients with ulcerative colitis.
Hart emphasized that there hasn't been much work on means of preventing the disease.
So he and colleagues conducted a prospective cohort study of 25,639 patients ages 40 to 74 who were enrolled in EPIC-Norfolk (European Prospective Investigation into Cancer). The patients, who were seen at local general practitioners' offices, were recruited between 1993 and 1997 and followed until 2004.
All patients completed a detailed seven-day food diary. Hart stressed that these journals were meticulously coded and interpreted by nutritionists.
Researchers monitored the cohort for patients who developed ulcerative colitis. These patients, who were followed for a median of 3.9 years, were each matched with an age- and sex-specific control.
In multivariate models, the researchers adjusted for factors such as smoking, as well as omega-3 and omega-6 polyunsaturated fatty acids, which also influence the inflammatory process via a different means from omega-9 fatty acids.
During the study, 22 patients developed ulcerative colitis.
The researchers found that those in the highest tertiary of dietary oleic acid intake had nearly a 90% reduced risk of ulcerative colitis (OR 0.11, 95% CI 0.01 to 0.87).
They also saw a significant trend across tertiles (OR 0.33, 95% CI 0.12 to 0.93, P=0.04).
Hart said that about half of the cases of ulcerative colitis could have been prevented if patients took larger amounts of oleic acid. In this study, two or three tablespoons of olive oil were associated with an effect.
Yet he cautioned that it's too early to make clinical recommendations for prevention.
"We need further research to determine if oleic acid is truly protective, and not just some other factor associated with a diet high in oleic acid," he said.
Hart told MedPage Today that future investigations into this relationship will show that it is far more complex. Omega-3 and omega-9 fatty acids may be beneficial, but omega-6 may not be.
Omega-6 fatty acids could increase inflammation, but omega-3 and omega-9 fatty acids may block the pathways that the omega-6 fatty acids act on.
DHA and EPA are the two omega-3 fatty acids that are associated with fish oil.
"Fish and olive oil will be important health foods in the future [treatment of ulcerative colitis]," he said, "if they're not already."
The study was limited by the fact that dietary journals were kept for only one week.
Kelly A. Tappenden, PhD, RD, of the University of Illinois, called the findings "very promising," but cautioned that moving forward, it's "Important to try and understand the other changes in diet associated with high oleic acid -- for example, dietary fiber, and pre- and probiotics."
"This is an exciting insight into fatty acids," she said. "Now we need to look at the other factors."
Primary source: Digestive Disease Week
Source reference:
de Silva PS, et al "Dietary oleic acid protects against the development of ulcerative colitis -- A U.K. prospective cohort study using data from food diaries" DDW 2010; Abstract 100.
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