[By Clara Hong]
When researchers took a close look at the foods typically eaten in various countries, they discovered an interesting insight: as fish consumption increased, depression decreased. An American who visits Japan cannot help but be struck by how relatively happy people there seem to be. Despite crushing workloads, an economy that’s been in the dumps for 15 years and grim, urban landscapes of concrete, the country’s residents generally seem to smile, laugh and exude a sense of contentment. Statistics back up that impression: The Japanese have the lowest rates of major depression in the developed world.
Conversely, rates of major depression in the United States – land of open spaces, higher incomes, more social freedom and relatively little overcrowding – are roughly 30 times higher. Of course, depression isn’t uniform in each country; it varies from city to city and town to town. But what is consistent is this: People who consume the most fish (found in Japan, Thailand, and Hong Kong) were the least depressed, while those with the lowest fish consumption (found in North America, Europe, and New Zealand) had the highest rates of depression. The secret seems to be the abundance of a particular type of fat found in fish (and in other foods): omega-3 fatty acids.
What’s the Japanese secret? At least part of it may be: Fish.
Specifically, the omega 3 fatty acids in seafood of all kinds. The average Japanese citizen eats about 145 pounds of fish annually, he said. The average American eats about 42 pounds. But there is more involved than sheer poundage of fish eaten. On May 1, at the Nutrition and Health Conference in New York City, sponsored by the University of Arizona’s College of Medicine and Columbia University’s College of Physicians and Surgeons, Hibbeln laid out his case that an imbalance between omega 3 and omega 6 fatty acids in the American diet is a modern nutritional disaster. This imbalance, he said, appears to contribute not only to depression, but also dyslexia, hyperactivity, even a tendency toward violence and murder. Conversely, he said, bringing the fats into proper proportion appears to drastically alleviate those conditions.
A closer look at the Japanese diet sheds more light on the fish-omega 3-depression link: Typically, about 15 times more omega-3s are in the diet of the Japanese than are in the American diet. Depression-wise, this translates into a Japanese culture with one-tenth the depression rate of Americans. Viewed from another vantage point, this means that almost 50% of elderly Americans have symptoms of depression, compared with about 2% of the Japanese elderly. Even more striking is the discovery in 1995 by psychiatrists who interviewed elders living in a Japanese fishing village: they did not find even one case of clinical depression.
Anatomy of Omega 3s and mood
How might Omega-3 fats ward off depression? One of the omega 3s — with the long name of docosahesaenoic (DNA) — is believed to boost the blues because it is concentrated in the brain. Contributing to about 50% of the total fats in nerve tissue, they play a key role in the functioning of nerve membranes, and in turn, your nervous system. Add the link between deficiencies in omega-3 fatty acids and low levels of serotonin, and you’re more vulnerable to depression.
Fish for feel-good feelings
From dreary doldrums to a deeper depression, a diet that is deficient in omega-3 fats can contribute to the problem. Here are some omega-3-rich fish to integrate into your diet. (Note. One serving is 3 ounces, before cooking.)
Omega 3 fatty acids are prevalent in fatty tissues of fish, and to a lesser extent in a plant- based sources such as walnuts and flaxseeds – in other words, they are fairly rare commodities in the standard American diet. Conversely, omega 6 fatty acids are the type prevalent in most vegetable oils, particularly soybean oil. Incredibly, production of soybean oil for food consumption in the U.S. has risen 1,000-fold from 1909 to 1999, and is part of virtually every fried or processed food Americans eat.
Still, many are afraid to eat more fish because of concerns over pollutants. Researchers advise eating fish that are relatively low on the food chain, which reduces accumulation of ocean-borne pollutants such as mercury in their tissues. “Larger, more carnivorous fish are more likely to contain dangerous levels of toxins. I avoid swordfish, marlin, shark, and bluefish for that reason,” Dr. Weil said. Dr. Weil’s recommendation, similar to that of Drs. Hibbeln and Deckelbaum, is to eat wild-caught salmon, herring, and sardines.
If you don’t want to eat more fish, try supplementing with fish oils. Seek out oils that receive a five-star rating from International Fish Oil Standards (IFOS), a Canadian organization that assesses the purity of commercial fish oil supplements. Visit their Web site for a list of IFOS-recommended fish oils (www.nutrasource.ca).