Fish Oil may also be good for your Brain
Written by: Laurie Rosenblum, MPH, Date: Sep. 9, 2004
Fats and oils in foods are made up of molecular components called fatty acids. Foods such as meat, butter, olive oil, or fish oil are composed of several different fatty acids—some of which are necessary or "essential" for human growth and development. Although the human body can synthesize most of the fatty acids it needs from what you eat, it cannot make certain fatty acids called essential fatty acids (EFAs), otherwise known as "omega" fatty acids. Therefore, EFAs must be consumed in the diet.
There are two types of omega fatty acids: omega-3 and omega-6. The 3 and 6 refer to where the first carbon double bond is located on the fatty acid chain. All essential fatty acids are polyunsaturated. Ideally, you need a balance of the two in your diet. However, Americans tend to consume too much omega-6 and not enough omega-3. Omega-3 fatty acids are highly concentrated in the human brain and are important for proper communication between nerve cells.
Omega-3 fatty acids are found in the highest concentrations in fish oil, canola oil, and flaxseed oil. Omega-3s are important for brain and vision development in infants and may affect learning, memory, and stress levels throughout life.
Recent studies have shown that people with a wide array of mental illnesses have a deficiency of omega-3s. A few studies have also demonstrated that fish oil can help treat some of these disorders, and more studies are in progress.
There are three types of omega-3 fatty acids: docosahexaenoic acid (DHA), eicosapentanoic acid (EPA), and alpha-linolenic acid (ALA). (Note that DHA is not the same as DHEA. DHEA is a steroid hormone.)
Foods containing omega-3 fatty acids include:
DHA and EPA - fatty fish such as salmon, sardines, mackerel, and bluefish.
ALA - plant sources such as flaxseed oil, canola oil, walnuts, and dark green leafy vegetables.
DHA is especially important for brain and visual development in infants. As it happens, breast milk is a better source of DHA than formula. Some studies even indicate that breast-fed babies consistently perform better on tests of visual and mental ability.
Recent evidence suggests that DHA may also affect learning, memory, and stress levels in adults. Some studies have linked DHA to a reduced risk of developing dementia as well as improvement in the mental state of people who already have dementia.
New studies also provide evidence of an association between low levels of omega-3 fatty acids and depression, bipolar disorder, attention deficit hyperactivity disorder, schizophrenia, alcoholism, and impulsive, violent behavior.
Several cultural factors encouraged researchers to pursue finding a connection between depression and omega-3 fatty acids. Such studies have shown that the rate of depression is much lower in countries such as Japan, where the native diet is rich in fish, than in the United States and many Western European countries, where the normal diet contains much less fish. Of particular interest is the fact that the amount of omega-3 fatty acids in the American diet has decreased during this century, while the rate of depression has increased.
The finding of abnormally low levels of omega-3 fatty acids in people with depression and individual case histories of successful treatment with omega-3 fatty acids raise the possibility that depression may be relieved by supplementation with omega-3 fatty acids. However, further scientific studies are needed.
Postpartum depression has also been linked to low levels of omega-3 fatty acids, particularly in women who are breast-feeding. This may happen because lactating women "lose" a fair amount of omega-3 fatty acids to their breast-fed infants.
Omega-3 fatty acids appear to have both antidepressant and mood-stabilizing effects. A 1999 Harvard Medical School study showed that people with bipolar disorder who were treated with fish oil (which contains DHA and EPA) and medication improved significantly more than those treated with medication and a placebo.
According to Andrew L. Stoll, M.D., principal investigator of this study and director of the Psychopharmacology Research Lab at McLean Hospital in Belmont, Massachusetts, "Fish oil is currently being used only as an adjunct to medication, except in mild cases where it may be tried before medication or when patients are having significant problems with medication."
No large studies have been performed with flaxseed oil, but the results in individual cases appear promising. Although both flaxseed and fish oils must be taken in large quantity, both appear to be safe and may provide additional health benefits, such as reduction in the risk of heart disease.
Studies are currently underway to determine whether supplementation with omega-3s can relieve some symptoms of ADHD and decrease or eliminate the need for medication.
"There is increasing research evidence that supplementation with EPA from fish oil as an adjunct to antipsychotic medication can decrease schizophrenic symptoms and the amount of medication needed," says Basant K. Puri, M.D., consultant psychiatrist and senior lecturer at Imperial College School of Medicine in London. In one case, a man who had not responded to any medications showed dramatic improvement in symptoms and brain structure when he took EPA and no medication. EPA may also reduce side effects of these medications.
Chronic alcohol use depletes the level of DHA in the brain. Researchers have hypothesized that the cognitive effects of alcoholism, depression, loss of memory, difficulty concentrating, and violent behavior are related to the depletion of DHA in the brain.
The link between omega-3 fatty acids and mental health and illness is a new and growing area of research with much to be discovered. According to Dr. Stoll, "There is a huge amount of promise, but not much data yet. We have to be careful in making recommendations for treating mental disorders until we have more successful research studies." So if you or someone you know has one of the disorders described above, look for new developments in treatment with omega-3 fatty acids.
When consuming essential fatty acids, try to balance your intake of omega-6 and omega-3s. But also keep in mind that you should limit your fat intake to about 30% of the total calories you consume.