Omega-3 fatty acids are a form of polyunsaturated fat or "good" fat.
Omega-3 fats help to prevent heart disease, reduce blood pressure, enhance mental health, and reduce the inflammation of arthritis, among other things. Omega-3 fatty acids cannot be made by your body, and therefore must be supplied by your diet.
There are three types of omega-3 fatty acids: DHA, EPA and ALA. Studies tend to show health benefits from the consumption of the DHA and EPA forms of omega-3 fatty acids, found in oily, cold-water fish such as salmon, tuna, mackerel, sardines, anchovies, herring and halibut, and in fish-oil supplements.
The beneficial effects of ALA are not as well-documented. ALA is contained in some nuts, pumpkin seeds and certain vegetable oils such as canola, flaxseed and olive oil. Your body also converts ALA into DHA and EPA.
The American Heart Association recommends eating fish, especially oily types of fish, twice a week, to help with increasing your intake of omega-3 fats. However, some types of fish may contain high levels of mercury which make them unsuitable choices for women who are planning to become pregnant or who are pregnant or breastfeeding, or for young children.
If you are thinking about taking omega-3 supplements, be sure to only purchase supplements from a reputable company which certifies that their products are free of contaminants. It's also important to consult a medical professional who can determine whether supplements are suitable for your particular circumstances and advise you on any potential side effects.