Fish oil capsules can be a good source of omega-3 fats. ­

iStockphoto/Hanquan Chen

­There's something fishy about the American diet. Or rather, something not fishy enough. According to many health experts, a key factor linking such common health conditions as heart disease, high blood pressure, obesity and diabetes is a dietary imbalance related to fat. It's not just that we consume too much fat but the wrong kinds. Specifically, we need to increase our intake of the beneficial essential fatty acids, especially omega-3 fats. The most important of these nutrients are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are "essential" because the body needs them and cannot make them on its own. Without a doubt, the best ways to get these nutrients are to eat fatty fish such as salmon and sardines or to take fish oil as a supplement.

The essential fatty acids include the categories of omega-3 and omega-6, which are distinguished from each other by the structure of their molecular bonds. Both are needed, but their proportion is very important. The omega-6 fats are found in a much wider range of nutritional sources, including most vegetable oils, eggs and cereal grains. For optimal health, the ratio of omega-6 to omega-3 in one's diet should be somewhere between even and 4:1. In the typical American diet, however, the proportion is as high as 20:1 [source: Larsen].

­The deficiency in omega-3 consumption may be responsible for a host of negative health repercussions, ranging from clogged coronary arteries to depression and attention deficit hyperactivity disorder (ADHD). Many of these symptoms relate in one way or another to inflammation, which some researchers believe is at the root of many diseases. Reducing inflammation may be the most potent effect of the omega-3 essential fatty acids.

This article will reveal why fish oil is one of the best-selling nutritional supplements on the market and explore some of the health benefits fish oil has been demonstrated to provide. Let's begin by looking at how the fatty acids function in the body.