Does fish oil help digestion? While most people benefit by taking fish oil, most people don't need fish oil for digestive support. People with ischemic and inflammatory diseases of the lower digestive tract, however, often discover that taking fish oil on a regular basis benefits many digestive conditions a lot more than the more frequently recommended digestive enzymes. Let's take a look at five digestive conditions fish oil can help.
Fish Oil for Ischemic Bowel Disease
Ischemic bowel disease is a condition about 20% of us eventually develop, but that most of us have never heard of. An ischemia is the failure of circulation to an organ. Ischemia may or may not kill an organ, but it will cause inflammation, tissue damage, and poor function. Ischemic bowel disease usually occurs when the inferior mesenteric artery fails to deliver enough blood to the left side of the colon.
Ischemic bowel disease may be gradual or traumatic. By age 85, experts estimate, about 20 to 25% of all people suffer a failure of the inferior mesenteric artery. If this happens slowly, the intestine has a chance to develop a parallel plumbing system that causes what I would call a "cranky" bowel.
Sometimes the bowels just won't move at all. Sometimes bowel movements are sudden, urgent, and voluminous. There can be no pain, or blinding pain, and defecation can be accompanied by loss of consciousness. This is a difficult condition to live with, but it is something most people can live with.
In younger people, however, dehydration can cause ischemic bowel disease. The inferior mesenteric artery essentially collapses when dehydration (usually following an athletic competition, such as triathlon), cutting off circulation to the bowel altogether. The surgeon is faced with a dilemma. If the bowel is left inside the body, it can turn gangrenous, and death can result in 1 to 2 days.
If the surgeon performs an emergency colostomy, there may not be enough time to clean the bowel to prevent infection. Up to 90 per cent of people admitted with this kind of ischemic bowel disease die in just 36 hours.
Fish oil can make living with degenerative ischemic bowel disease easier. And it can help people recover from traumatic ischemic bowel disease, although it is absolutely no substitute for medical care.
If you have survived the traumatic kind of ischemic bowel disease (and I myself have), one of the things that will occur is that the outer layers of the intestine will shed like injured skin. And since you will be put on a low-fiber, high-fat diet (unless you have high cholesterol, in which case the dietitian will be suggesting you try to live on broth and Jell-o), taking liquid, not encapsulated, fish oil can help reduce inflammation so that you bleed less and pass less scar tissue. Liquid fish oil, a teaspoon (5 ml) to a tablespoon (15 ml) a day, helps. You don't to take more than that, however, until you are well enough to eat solid food as well as fruit and vegetables, usually a few weeks to a few months after your injury.
If you have the "slow" form of ischemic bowel disease, then taking fish oil regularly will reduce inflammation in general. Two studies involving laboratory animals found that the omega-3 essential fatty acids in fish oil slow down the action of white blood cells known as neutrophils in releasing inflammatory hormones in the lining of the intestine. You will probably do better by taking liquid fish oil, too, although any brand that has a very high essential fatty acid content (such as Xtend Life or New Vitality) will allow you to take fewer capsules a day to get the omega-3's you need. Two or three capsules of Xtend-Life or New Vitality per day is enough. You would need 12 to 15 capsules of the brands of fish oil you can get at Walmart, Costco, or Target.
Fish Oil for Inflammatory Bowel Disease
Fish oil is also helpful for people who have inflammatory bowel disease, such as ulcerative colitis or Crohn's disease. Doctors have studied fish and fish oil for treating these conditions in clinical trials.
Physicians at the Stavanger Hospital in Norway biopsied colon tissue of people who had ulcerative colitis who had been asked to eat more Atlantic salmon. (To me, these people made a considerable sacrifice for science, colon biopsies not something I care to volunteer for.) The biopsies showed that omega-3 essential fatty acids were being incorporated into tissues. This explains the findings of statisticians at Hebrew University in Jerusalem that long-term use of fish oil results in about 14% fewer relapses of inflammatory bowel disease.
In other words, fish oil won't cure ulcerative colitis or Crohn's disease. But if you take fish oil, you may experience the worst symptoms of inflammatory bowel disease significantly less often.
The essential fatty acid in fish oil that seems to be most closely connected with relief from symptoms is EPA, rather than DHA. This just means that you don't need to take a "high-DHA" fish oil, since most formulations of fish oil are naturally higher in EPA than in DHA. It also means that you take fish oil rather than any essential fatty acid supplement made from microalgae, since plant oils don't contain EPA. If you have inflammatory bowel disease, I'd recommend Nordic Naturals over Xtend Life. They are both excellent products, but Nordic Naturals will do more good for inflammatory bowel disease.
People who have ulcerative colitis usually get faster results from taking fish oil than people who have Crohn's disease. It helps in both conditions, but the oil has greater contact with the bowel in ulcerative colitis than in Crohn's disease. Also, the more inflamed the bowel is in ulcerative colitis, the longer it will take to see results.
What about Fish Oil for Stomach Ulcers?
Fish oil can be very helpful in the early stages of treating stomach ulcers. Polyunsaturated fatty acids like those found in fish oil slow the growth of Helicobacter pylori, the bacterium associated with a majority of cases of gastric or duodenal ulcers. A high-DHA fish oil will be as helpful as a high-EPA fish oil.
Once the stomach has begun to mend, however, the benefits of fish oil are not as noticeable. That does not mean you necessarily should stop using it. It can help prevent reinfection by helping to stop the inflammation that helps the bacterium re-establish itself in the lining of the stomach. Almost any brand of fish oil will help, although you can take fewer capsules of Xtend-Life, Nordic Naturals, or New Vitality. Two or three capsules a day of any of these brands is an appropriate dosage for people who have gastric or duodenal ulcers.
What about Fish Oil for Pancreatitis?
Scientists at the Indiana University Medical Center have done a preliminary study of fish oil in treating pancreatitis with mice in the lab. The preliminary results suggest that fish oil is most likely to be helpful when obesity is a complicating factor in the disease. Of course, when high triglycerides are the reason for the disease, fish oil is likely to be especially helpful.
If you are having to deal with vomiting and diarrhea caused by acute pancreatitis, I don't recommend you try to hold down fish oil, too. Where taking one or two capsules a day may help is in extending your remission from pancreatitis, especially if you have to take a medication that can trigger a new attack, such as estrogen or birth control pills.
What about Taking Fish Oil to Prevent Colon Cancer?
A question I get asked with some frequency is whether one should take fish oil to prevent colon cancer. I answer with "It depends."
There is no doubt that omega-3 essential fatty acids fight inflammation, but there is considerable doubt as to whether they reliably reduce the risk of colon cancer. The North Carolina Colon Cancer Study, for example, found that that whites who consumed 180 mg of omega-3 essential fatty acids a day or more had a 51% lower risk of colon cancer. Blacks who 180 mg of omega-3 essential fatty acids a day or more did not have a lower risk of colon cancer. For Blacks, the data were ambivalent.
The Singapore Chinese Health Study found that increased consumption of omega-3 essential fatty acids from fish lowered the risk of rectal cancer but had no effect on the risk of colon cancer, among Chinese people. The Physician's Health Study found a protective effect of total omega-3 essential fatty acids against colon cancer in men of all races, but didn't consider the benefits of fish oil for preventing colon cancer in women.
The Singapore Chinese Health Study identified a specific gene associated with benefiting from fish oil for preventing colon cancer. Until these findings can be generalized to other populations, however, I don't recommend taking fish oil for the prevention of colon cancer if you have African ancestry. If you have European or Chinese ancestry, then it is probably a good idea, although there are different benefits for some Chinese people. There are not yet data for other groups.
Frequently Asked Questions
Q. Why does fish oil make me have diarrhea?
A. Probably it is not fish oil that is causing stomach upset, but rather the impurities that some companies allow to be included in the mix. If you take a brand of fish oil that has at least 400 mg of DHA + EPA essential fatty acids in each capsule, such as New Vitality or Xtend-Life Omega 3/DHA Fish Oil, there is not enough room in the capsule for the "marine liquids" that cause stomach upset in some people.
Q. I have short bowel syndrome. Should I take fish oil?
A. For those reading who do not know, in adults short bowel syndrome is a condition in which two-thirds of the large intestine has been removed. People who have short bowel syndrome have trouble absorbing nutrients digested from food, especially fats. Unless your doctor tells you to take more, I wouldn't recommend trying more than one capsule of fish oil a day, and stopping even that dosage if there were oily or sticky stools. Cod liver oil (just one teaspoon) is preferable because there the digestive tract does not have to break down the capsule, and there are additional fat-soluble vitamins A, D, and K in the oil.
If you have short bowel syndrome, do not take an enteric-coated capsule, which has to break down in the intestine instead of the stomach. New Vitality fish oil comes in enteric-coated capsules.
Q. Is fish oil a remedy for appendicitis?
A. Absolutely, positively not! Appendicitis requires emergency medical care.
- Grimstad T, Berge RK, Bohov P, Skorve J, Goransson L, Omdal R, Aasprong OG, Haugen M, Meltzer HM, Hausken T. Salmon diet in patients with active ulcerative colitis reduced the simple clinical colitis activity index and increased the anti-inflammatory fatty acid index-a pilot study. Scand J Clin Lab Invest. 2011 Feb;71(1):68-73. Epub 2010 Dec 8.
- John S, Luben R, Shrestha SS, Welch A, Khaw KT, Hart AR. Dietary n-3 polyunsaturated fatty acids and the aetiology of ulcerative colitis: a UK prospective cohort study. Eur J Gastroenterol Hepatol. 2010 May;22(5):602-6.
- Meister D, Ghosh S. Effect of fish oil enriched enteral diet on inflammatory bowel disease tissues in organ culture: differential effects on ulcerative colitis and Crohn's disease. World J Gastroenterol. 2005 Dec 21;11(47):7466-72
- Turner D, Shah PS, Steinhart AH, Zlotkin S, Griffiths AM. Maintenance of remission in inflammatory bowel disease using omega-3 fatty acids (fish oil): a systematic review and meta-analyses. Inflamm Bowel Dis. 2011 Jan;17(1):336-45. doi: 10.1002/ibd.21374. Review.