Kosher fish oil is fish oil which has been prepared in accordance with Jewish dietary law. Kashrut or “kosher” rules dictate the types of foods which people can eat, and finding kosher dietary supplements can sometimes be challenging, as the Jewish market for such products is relatively small. For people of the Jewish faith who want to keep kosher while complying with health recommendations, kosher supplements are often significantly more expensive than regular supplements, due to the increased difficulty involved in production.
In order to be certified kosher, a fish oil must not include any non-kosher animals. Kosher fish must have fins and scales, and by tradition, it should be possible to remove the scales without killing or seriously harming the fish. The fish used in the production of kosher fish oil must be carefully inspected to confirm that they are kosher species, and the production facility should also be certified as kosher, confirming that non-kosher materials are not handled there, or that they are carefully isolated to prevent cross-contamination.
Fish oil is a dietary supplement rich in omega-3 fatty acids, a class of compounds which are believed to be highly beneficial to human health. Most notably, fish oil contains a lot of docoahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Fish obtain omega-3s from the algae they eat, and from consuming other fish who have accumulated these lipids in their bodies. The more oily a fish, the more omega-3s it has.
Research in the 1960s suggested that fish oil provided a number of health benefits, and this product became quite popular as a result. However, fish oil is not without issues. Along with omega-3s, fish tend to bioaccumulate fat-soluble toxins like mercury which can be passed on to consumers who eat a lot of fish oil or oily fish. Kosher fish oil tends to be lower in such impurities, due to the type of fish used, which can make it appealing to people who are concerned about toxins; kosher fish oil is also typically safe for pregnant women.
If a product is certified as kosher, it will be clearly marked as kosher or kashrut, sometimes with a U-shaped pareve symbol. Devout Jews may want to consult with a rabbi or religious authority to confirm that it is acceptable to consume a particular product. Consumers should also be cautioned that claims about impurities or the lack thereof are not usually reviewed by government agencies, which means that if a kosher fish oil claims to be “low in mercury,” this has not been independently verified.