Fish Oil Helps Treat Depression
Studies: Fish Oil Contains Natural Ingredients That Help Treat Depression Omega-3's may have an affect on serotonin levels.
By John McKenzie
For years, researchers have been searching the seas, collecting rare sponges, coral and algae in the hope that the chemicals they contain might become potent medications.
Now some researchers say they've found an effective antidepressant below the waves: Fish, or more specifically, fish oil containing so-called omega-3 fatty acids.
"We've been very impressed by the response rates we've observed," said Dr. David Mischoulon, a psychiatrist at Massachusetts General Hospital who has overseen an omega-3 clinical trial. "We believe there is definitely something to these treatments."
Scientists first became interested when they noticed that countries with the highest fish consumption had the lowest rates of depression. They also observed that mothers in England who ate very little fish during pregnancy doubled their risk of developing postpartum depression compared to women who ate fish regularly. So scientists began a series of studies to see why.
Omega-3 Fatty Acids Found to Have Same Effect
Researchers found that omega-3 fatty acids, when fed to piglets, had the same effect on the brain as the antidepressant Prozac: They raised levels of a critical neurotransmitter, serotonin.
"After only 18 days, those animals that were fed the enriched formula had double the level of serotonin in their frontal cortex, in the part of the brain that regulates depression and impulsivity," said Dr. Joseph Hibbeln, a senior clinical investigator at the National Institutes of Health.
Omega-3 fatty acids are polyunsaturated oils that cannot be made by the body and are derived primarily from seafood. The fatty acid with most direct influence on brain development and function is DHA.
"The DHA is highly concentrated in the brain," Hibbeln told ABCNEWS, "and it's concentrated in the brain right where the neurons communicate with each other and all the signals pass back and forth."
The DHA from omega-3 makes up the walls of neurons, Hibbeln said. "The body cannot manufacture DHA so it has to get it from our diet."
At Sheffield University in England, Dr. Malcolm Peet gave omega-3 fatty acids to 70 depressed patients who had not been helped by drugs such as Prozac. After 12 weeks, 69 percent of the patients showed marked improvement compared with 25 percent given placebos.
Trial Participant Accounts Significant Improvement
Jim LaBonte of Boston took part in another omega-3 study. LaBonte, who was diagnosed with depression four years ago, had tried Prozac but didn't like the way it made him feel. He complained the drug left him with no emotions, and so he stopped taking it. Then he enrolled in a clinical trial at Massachusetts General Hospital.
"I leaned more toward the skeptical. I wanted to say, 'show me,' " LaBonte told ABCNEWS.
LaBonte took the omega-3 fatty acid DHA each day. Within three weeks, he said, he noticed a significant improvement. He has now been taking DHA for eight months.
"I'm fine today. Not only do I not feel as blue, but when they [depressed feelings] do come I am able to handle it," he said.
"We're confident that the results he had were positive," said Mischoulon. "We've also observed similar responses in other people. So it's pretty clear in our minds that these treatments work."
Preliminary studies suggest 1 gram a day of omega-3 fatty acids can be an effective treatment, whether in the form of a nutritional supplement available at most health-food stores or simply by eating fish — especially salmon, sardines or tuna — several times a week.
Researchers say much larger studies are now needed to follow up on the initial success of omega-3 trials, not only against depression but also in treating schizophrenia, bipolar disorder, and violent behavior.
WebMD Feature
Dave thinks a lot about fish these days. Study after study has suggested benefits for omega-3 fatty acids, which are plentiful in certain fish oils. But what intrigues Dave isn't that omega-3's might reduce his risk of heart attack, or ease the pain of arthritis. He's hoping to lubricate his mind.
A handful of small studies have suggested that omega-3 fatty acids can help smooth out the mood swings of bipolar disorder. There are few effective treatments against the disease, so the news is a hot topic now at support groups for manic-depressives, like the Berkeley, CA, group in which Dave participates.
The first news to attract attention was a 1998 report in the Journal of Affective Disorders. Researchers noted significantly lower levels of omega-3's in the red blood cell membranes of patients with depression.
Then in the May 1999 Archives of General Psychiatry, Andrew Stoll, M.D., and colleagues reported a study of fish oil in 30 manic-depressive patients. Sixty-four percent of those who took 10 grams of fish oil per day for four months reported a marked improvement in their symptoms. By contrast, only 19 percent of those receiving the placebo benefited.
Cell Softeners?
These studies aren't the only research that points to the benefits of fish oil for mood problems. "There are a lot of reasons to believe it works," says Stoll. "In countries where the average fish consumption is high we see lower rates of depression."
On the biochemical front, researchers point out that cell membranes are made up partly of omega-3's. It is possible that increasing the omega-3 levels makes it easier for serotonin -- a chemical that carries messages from one brain cell to another -- to pass through cell membranes. "Research still needs to be done on the exact mechanisms involved," Stoll notes, "but we do know that omega-3 does affect the membranes and changes functioning." And increasing omega-3 "has direct effects on serotonin levels."
Diet and Depression
Joseph Hibbeln, M.D., a psychiatrist at the National Institute of Health, thinks omega-3's might explain why the rate of depression is rising in the United States.
In a health-conscious push to rid our diets of saturated fats and cholesterol, Americans have been eating less red meat and eggs -- two good sources of omega-3's. Furthermore, we have been switching to the polyunsaturated fats, such as corn, soybean, and sunflower oils, which are relatively low in omega-3's.
Supplement or Go Fish
But just how to mend that situation remains controversial. Omega-3's might worsen some chronic illnesses. (Check with a doctor if you have such a condition before starting to take supplements.) The Food and Drug Administration is now considering what quantity of omega-3's to recommend; currently it has no recommendation but classifies three grams per day as "safe."
Though Stoll gave patients 10 grams of fish oil a day for his study, he advises starting with lower doses. He believes that packaged fish oil supplements are the easiest -- and possibly safest -- way to increase omega-3 levels.
"Unfortunately in our country eating too much fresh fish is potentially dangerous because of possible mercury and pesticide levels," he explains. "Farm-raised fish is perhaps safer, but depending on what they are fed, the fish may not have the needed quantity of omega-3's."
But concerns have also been raised about the levels of contamination in fish oil supplements. Regulators do not currently test the purity of supplements.
Hibbeln cautions that people should not take cod liver oil in the quantity necessary to get three grams per day of omega-3's because that much cod liver oil would contain dangerous levels of vitamin A.
On the other hand, flaxseed oil is a good source of omega-3's. It can be taken as a supplement or used in salad dressings. Unlike fish oils, which contain a different combination of omega-3's, flaxseed oil should not be cooked because heat can destroy the omega-3's.
More answers are expected soon. The National Institute of Mental Health's Center for Complementary and Alternate Medicine is sponsoring Stoll in a large new study, one of three now under way. All three are expected to be complete by the end of next year.
But Dave probably won't wait for the results. "Looks like I need to go out and get myself some fish oil," he says.
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