You need omega-3 fatty acids as part of your diet. The body partially converts the form found in plant sources such as flaxseed to the form provided by fatty fish. According to Harvard professor Dr. Frank Sacks, most Americans don’t get enough of either form -- a minimum of one serving a day. Fish oil supplements are readily available, but they're not all created equal. Omega-3 is a delicate fatty acid that is easily damaged by processing. Taking rancid or contaminated fish oil supplements is worse for your health than taking none. Read the label to get a supplement of good quality.
Purity and Freshness
Quality brands will indicate on the label that the product has been molecularly distilled. This means that the oil has been processed to separate it from environmental toxins that might be present such as heavy metals, dioxin and PCBs. To reduce contamination and spoilage, some commercial fish oils are extracted from small cold-water fish such as sardines and anchovies, which tend to accumulate fewer toxins, and add an antioxidant such as vitamin E or rosemary extract to prevent oxidation. A possible indication fish has been damaged is digestive discomfort after taking it, sometimes called the “fish burp.”
Natural Triglyceride Form
The fats and oils in your diet exist in the form of triglycerides -- fatty acids attached to a backbone of glycerol. Your gut enzymes recognize triglycerides and properly digest them and allow for their proper absorption and metabolism. Some types of processing disrupt the fish oil's triglyceride structure, which may interfere with proper digestion and metabolism, unless the disruption is reversed. Better quality fish oil supplements will indicate on the label that they are restored to triglyceride form.
The omega-3 fatty acids in fish oil -- EPA and DHA -- occur naturally in a ratio of about 3-to-2, or 180 milligrams of EPA to 120 milligrams of DHA per 1,000 milligrams of oil. Therefore, only 30 percent of natural fish oil is in the form of EPA/DHA, and the rest is composed of other fatty acids. Concentrated varieties of fish oil are available that provide a higher concentration of EPA/DHA. This enables you to get more of the active ingredient by taking fewer capsules. Ask your doctor to help determine the optimal dose for you.
Other Marine Oils
Cod liver oil is different than regular fish oil, or “fish body oil" as it provides a higher ratio of DHA to EPA. Both are important, but DHA supports brain development, especially in children. However, regular doses of cod liver oil potentially provide toxic levels of vitamins A and D, so you need to look for brands that have reduced the vitamin content. And always consult your pediatrician before giving it to your kids. Krill oil, another option, is derived from a shrimplike animal whose natural red pigment is a source of a carotenoid called astaxanthin, an antioxidant that might support brain health.