As the days grow shorter, considering the role of omega-3s in keeping everything sunny
Seasonal Affective Disorder (SAD) was discovered by Dr. Norman Rosenthal after noticing that his own sluggish mood -- first noticed after moving from sunny South Africa to New York -- improved after exposing himself to bright light. SAD affects about 8 percent of people in wintry New Hampshire but less than 2 percent in Florida. Lack of sunlight may alter sleep-wake cycles by means of nerve signals from the eye to the brain's biological clock (the suprachiasmatic nucleus) with the help of melatonin from the pea-sized pineal gland.
Although Iceland's daylight diminishes, due to their near-arctic latitude, from over 9 hours on October 20 to just over 4 hours in December, its SAD prevalence of less than 4 percent is much lower than that of U.S. or European locations with equivalent levels of seasonal darkness. In fact, Icelanders are among the happiest people in the world -- despite their 2008 financial crisis, volcanic eruptions, and the predominant winter darkness.
In addition to their helpful social support and encouragement of out-of-the-box lifestyles -- the mayor of the city of Reykjavik, Jon Gnarr, who is also a comedian, as an example -- Icelanders believe that their high consumption of ocean fish and fish oil helps them cope. Oil-rich cold-water fish like salmon, cod, and sardines, fish oil supplements, and some plant-based foods like walnuts contain omega-3 polyunsaturated fatty acids, which research on other mood disorders suggests have an antidepressant effect. We've known for quite a while that eating fish correlates negatively with major depressive disorder.
Omega-3s affect the nervous system in other ways as well, which we're still coming to understand. We do know that nerves in the brain are so sensitive to omega-3 levels that a deficiency leads to problems with learning and memory, and evidence shows supplementation may protect against nerve damage due to trauma or aging. Omega-3s can change the composition of the membranes that surround cells in the brain and blood, and may improve their ability to function.
It's not just the absolute amount of omega-3s that you take in, but also the amount relative to your levels of omega-6 fatty acids. The risk for depression may increase with a high ratio of omega-6 fatty acids -- found in corn, safflower, and soybean oil, and common in processed foods -- to omega-3s.
Aside from medical science, Nobel-prize winning Icelandic author Halldor Laxness wrote a book titled The Fish Can Sing (in the English translation), in which he imagines that humble fish, the foundation of Iceland's economy, can "sing like a bird." It might be worth considering that bubbly thought as the days grow shorter.