Benefits of Fish Oil
Some studies suggest that high doses of fish oil may help cancer patients slow down their weight loss, but other studies have not shown any benefit. In general, people are more interested in fish oil for weight loss. Studies with mice and rats have shown that fish oil (or at least the omega-3 fatty acids in it) may have a role in weight loss and fat loss, but human studies in this area are lacking. It is too early to tell if taking fish oil can help people lose weight. It is important to remember that these supplements are not free of calories or fat.
There is growing evidence that fish oil supplementation may be an effective part of rheumatoid arthritis treatment. Studies suggest that it can help reduce rheumatoid arthritis symptoms, such as morning stiffness, and that it may be beneficial used alone or in combination with other medications. Some studies have also shown that people with rheumatoid arthritis who take fish oil may be able to reduce their use of nonsteroidal anti-inflammatory drugs (NSAIDs).
(For more information, see Fish Oil and Rheumatoid Arthritis.)
Pregnancy and Childhood
Early studies suggest that fish oil may decrease the risk of recurrent miscarriages in women with antiphospholipid syndrome (APS). Also, fish oil is a good source of omega-3 fatty acids, which may improve brain and eye development when taken during pregnancy and breastfeeding. However, keep in mind that some fish (and some supplements) may contain heavy metals and other toxins that are especially dangerous for pregnant women. Do not take these supplements during pregnancy without first talking to your healthcare provider, who can direct you to a supplement that is safe for pregnant women (see Pregnancy and Fish Oil for more information).
Early evidence suggests that fish oil may help children with attention deficit hyperactivity disorder (ADHD) or other developmental problems, although you should not give a child fish oil supplements without the approval of the child's healthcare provider.