Over the years, our diets have changed from high in omega-3 fatty acids to high in omega-6. And guess what? These days, we're a lot more depressed. At least two studies point to a link among countries with high rates of depression and low rates of fish consumption. This is not the same as showing a cause and effect, but an easy way of demonstrating a direct link would be to administer omega-3 to depressed individuals and see what happens.

Alas! The omega-3 hypothesis proved as simplistic as the chemical imbalance serotonin myth. Yes, we now have some pretty interesting evidence in its favor, but no, taking omega-3 is not going to just automatically make your depression (or mania) go away

The two active ingredients of omega-3 fish oil are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). EPA is considered to be the ingredient with the therapeutic effect, so it is important to buy omega-3 that contains more EPA than DHA. A zillion different biochemical mechanisms have been proposed for its mood-enhancing effect, which translates to we have no idea how the stuff works. One possible explanation is that it works like a calcium channel blocker, not unlike a mood stabilizer.
Omega-3 competes with its sister fatty acid, omega-6, for the same enzyme chain. From there, omega-3 and omega-6 are metabolized, then stored as highly unsaturated fatty acid in tissue phospholipids. Owing to high mercury levels (and other contaminants) in cold water fish, supplements may be the preferred option in any omega-3 strategy.
The 1999 Harvard pilot study that got people's notice was conducted on 30 patients with bipolar disorder, generally in stable condition but with a history of relapses (all had experienced bipolar episodes over the past year). All but eight of the subjects were on medications, which were left unchanged. Half the subjects were given 9.6 grams of fish oil capsules, the other half received olive oil.
After four months, those in the omega-3 group stayed in remission significantly longer than the placebo patients. The omega-3 group actually did less well in lowering their mania scores than those taking placebos, but fared much better getting their depression down.
A larger 2006 multi-center trial failed to duplicate the results of the Harvard study.
Various small studies have yielded promising results for depression, but the type of blockbuster study that would justify people changing their habits is lacking.
Thus, as a substitute for meds you are betting your life on the outcome, though there would be an exception for pregnant women. Otherwise, it is advisable to experiment with the supplement as an augmenter to whatever other treatment you may already be on. Keep in mind omega-3 carries a mania risk.
Less may also be more. Large doses may result in oxidative stress as omega-3 is being metabolized. This may explain why some studies using EPA failed at higher doses. To offset this, two prominent omega-3 researchers (Jerry Cott of the FDA and Andrew Stoll who did the Harvard pilot study) advise taking vitamins C and E with the omega-3.

Omega-3 in Your Food

Salmon is an obvious source of omega-3, but be advised that the salmon you find in most outlets is farm-raised and fed on grain, which does not contain omega-3, plus fish meal to artificially boost omega-3. In more expensive ocean-caught salmon, the omega-3 travels up the food chain from algae.

According to the FDA, salmon has low mercury concentrations compared to some other types of fish, and should be considered safe when eaten in moderation. Oysters, whitefish, sea bass, freshwater trout, and sardines are also high omega-3-low mercury sources. Fresh tuna and more expensive canned and albacore tuna contain nearly the same amount of omega-3 as salmon, but three times as much mercury, while canned light tuna is low in omega-3 and mercury. A two-ounce serving of canned albacore, according to one manufacturer, has 2.2 grams of omega-3.
Carnivores may want to consider switching to grass-fed beef, which is much higher in omega-3 and lower in saturated fats than the grain-fed, hormone-injected marbled slabs that end up on our tables. Grain-fed beef has a 20 to one ratio of omega-6 to omega-3, while grass-fed beef is about three to one. The ideal diet is considered to comprise equal parts omega-3 and omega-6. New Zealand and Australian beef come from grass-fed cattle, as do certain meats from various parts of Europe. US producers are beginning to fill a high-priced niche, and buffalo is another option.

Those who opt for meatless alteratives may want to consider flax. Emperor Charlemagne was such a great fan of the grain that he required his subjects to eat it. Flax seed contains just one type of omega-3, so it is advisable to keep eating fish. Most capsules contain 1,000 mgs of flax oil, although it is not yet clear how much flax the body needs. Flax seed is also a rich source in ligands (which may prevent some hormonally-related cancers) and fibers (the oil alone does not have ligands or fiber). If you buy flax seeds, be sure they are ground or that you grind them, as the body cannot digest the seed's outer hull. The active ingredient in flax oil is alpha-linolenic acid, which is converted to EPA and DHA in the body.

source : mcmanweb