Several years ago, one of my college roommates was told by her doctor that if she were to take only one nutritional supplement, it should be fish oil. There are good reasons for that recommendation. Fish oil—and, of course, the oily fish it's derived from, such as salmon, tuna, and sardines—contain high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential omega-3 fatty acids. These acids are "essential" in the sense that our bodies need them to function normally but have to rely on food or supplements to get them. Unfortunately, the typical Western diet is extremely low in omega-3, leaving most of us vulnerable to a host of bodily complaints.
Fish oil's most demonstrable benefits are to the cardiovascular system, where it does a lot of work toward preventing and reversing risk factors and symptoms of heart disease. Its natural anti-inflammatory properties have also implicated it as a treatment for many types of aches and pains. Other uses of fish oil, from the treatment of eczema and psoriasis to the prevention of cancer, have been studied to varying degrees but rarely enough to prove their worth. However, because omega-3 acids are involved in forming cell membranes, the notion that fish oil could improve the function of every part of the body from the skin to the brain is not so far-fetched.
Uses of Fish Oil
The most common use for fish oil is probably the regulation of cholesterol. Clinical trials have shown that a combination of EPA and DHA, the omega-3 fatty acids found in fish oil, lowers triglyceride levels and slightly increases concentrations of HDL cholesterol in the blood. This is good, since triglycerides are essentially fat floating around in the bloodstream, and HDL cholesterol is the "good" stuff that helps to transport "bad" LDL cholesterol out of the body. Unfortunately, fish oil has also been shown to cause a small increase in LDL cholesterol, which could offset its benefits for some people with elevated cholesterol.
Fish oil also promotes cardiovascular health by slightly lowering blood pressure. Doctors and scientists aren't exactly sure how it does so, but some studies have indicated that fish oil helps blood vessels function better, decreases resting heart rate, and may even reduce fatty buildup on arterial walls. There is evidence to suggest that DHA is more involved in lowering blood pressure than EPA, but because so many other cardiovascular benefits of fish oil rely on the two together, it's probably best to use a supplement that contains both. You may also need to take a lot of fish oil to see a measurable decrease in blood pressure, and since high doses can increase the risk of bleeding problems, you should work with a doctor when using fish oil to treat hypertension.
Fish oil is gaining popularity as a treatment for rheumatoid arthritis. Omega-3 fatty acids have long been known to have anti-inflammatory properties, so it makes sense that they would combat the pain of a disorder characterized by joint inflammation. Fish oil isn't effective against all the symptoms of arthritis, but patients with RA have reported experiencing less joint sensitivity and morning stiffness while taking fish oil supplements. Some studies suggest that fish oil may be especially effective when combined with standard medical treatments for arthritis and may actually amplify the effects of anti-inflammatory drugs like ibuprofen.
In the past few years, fish oil has gotten a lot of press as a possible way to ward off Alzheimer's disease and other forms of dementia. In fact, studies of fish oil's effectiveness against dementia have come up with varied and sometimes contradictory results. But some researchers have observed that the DHA present in fish oil prompts brain cells to produce more of a protein called SorLA or LR11, which in turn helps thwart the development of beta-amyloid plaque in the brain. Because this beta-amyloid plaque is a major symptom in patients with late-onset Alzheimer's, fish oil may very well help prevent dementia. However, it seems to have little effect once the disease has begun to progress.
Fish oil is increasingly being recommended by doctors as a treatment for mood disorders such as ADHD, depression, and bipolar disorder. Again, relevant studies have so far come up with a range of results, suggesting everything from zero to astounding mood-stabilizing properties. But some research has shown a link between depression and low levels of EPA, and since omega-3 is involved in the structure of cell walls—including the walls of neurons—adequate levels of DHA and EPA may help the natural mood regulator serotonin pass more easily into cells. There is also some evidence that anti-depressant medications are more easily absorbed by patients taking fish oil supplements, so they are usually prescribed in addition to, not instead of, standard mood regulators.
More Fish Oil Uses
Fish oil has been touted as a miracle solution to dozens of discomforts and illnesses, and since empirical study has shown that there's truth to some of those claims, fish oil has earned a deeper scientific look than many other natural remedies. Still, evidence to support most of its uses is spotty. We've already gone over some of the most common and well-supported uses for fish oil, but a few others look promising enough to be worth mentioning.
Fish oil may reduce the inflammation and pain associated with various forms of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease.
Omega-3 fatty acids are important for prenatal brain development and have been linked to improved behavior, problem-solving abilities, and communication skills in young children. Fish oil should definitely be consumed during pregnancy, but experts disagree on the best way to do that. To get adequate omega-3 while avoiding mercury, which can harm a fetus's developing brain, either take a purified fish oil supplement, or stick to fish low in mercury, like salmon, cod, halibut, or "light" canned tuna.
Because omega-3 fatty acids are known to decrease inflammation, it makes sense that fish oil could alleviate some of the pain of menstrual cramps, which result at least partially from uterine inflammation. Studies show that adding a B12 supplement could reduce the pain even more.
Some research supports the idea that fish oil may help to decrease the chronic bronchial inflammation at the root of asthma. People whose asthma symptoms are triggered by aspirin should steer clear of this treatment, however, because fish oil seems to make their asthma worse.
Some studies suggest that fish oil could help prevent various types of cancer. It looks especially promising as a way to inhibit the growth of polyps associated with colon cancer.