What should fish oil contain

Cardiovascular disease Many studies show that eating fatty fish and other types of seafood as part of a healthy eating pattern helps keep your heart healthy and helps protect you from some heart problems. The American Heart Association AHA recommends eating one to two servings of seafood per week to reduce your risk of some heart problems, especially if you consume the seafood in place of less healthy foods.

For people with heart disease, the AHA recommends consuming about 1 g per day EPA plus DHA, preferably from oily fish, but supplements are an option under the guidance of a healthcare provider. The AHA does not recommend omega-3 supplements for people who do not have a high risk of cardiovascular disease. Examples are salmon, herring, sardines, and trout. Breast milk contains DHA. Most commercial infant formulas also contain DHA.

Cancer prevention Some studies suggest that people who get more omega-3s from foods and dietary supplements may have a lower risk of breast cancer and perhaps colorectal cancer. But a large clinical trial found that omega-3 supplements did not reduce the overall risk of cancer, or the risk of breast, prostate, or colorectal cancers.

Other clinical trials in progress will help clarify whether omega-3s affect cancer risk. More study of the effects of omega-3s on the brain is needed. Studies suggest that people who get higher amounts of omega-3s from the foods they eat may have a lower risk of developing AMD.

But once someone has AMD, taking omega-3 supplements does not keep the disease from getting worse or slow down vision loss. Some studies show that getting more omega-3s from foods or supplements—mainly EPA and DHA—helps relieve symptoms of dry eye disease.

But a large, recent study found that the symptoms of people with dry eye disease who took fish oil supplements of 2, mg EPA plus 1, mg DHA daily for 1 year did not improve any more than those who took a placebo a dummy pill.

More research on the effects of omega-3s on dry eye disease is needed. Rheumatoid arthritis RA RA causes chronic pain, swelling, stiffness, and loss of function in the joints.

Some clinical trials have shown that taking omega-3 supplements may help manage RA when taken together with standard RA medications and other treatments.

For example, people with RA who take omega-3 supplements may need less pain-relief medication, but it is not clear if the supplements reduce joint pain, swelling, or morning stiffness.

But more research is needed to fully understand the potential benefits of omega-3s for these and other conditions. The U. Any side effects from taking omega-3 supplements are usually mild. They include an unpleasant taste in the mouth, bad breath, heartburn, nausea, stomach discomfort, diarrhea , headache, and smelly sweat.

Omega-3 dietary supplements may interact with the medications you take. In , survey data suggested that females who take probiotics, vitamin D, fish oil supplements, or a combination of these may have a slightly lower risk of developing COVID However, this investigation has not yet undergone peer review, and the findings are far from conclusive. In fact, experts have warned against using supplements in an attempt to prevent infection with the virus.

For more information on the COVID outbreak and advice on prevention and treatment, see our live updates page and visit our coronavirus hub. Some people with multiple sclerosis MS take omega-3 because it may have protective effects on the brain and the nervous system. However, at least one study has concluded that omega-3 supplements do not reduce disease activity with MS. Some research has suggested that eating a diet rich in omega-3 may help prevent prostate cancer. However, a study suggested that a high fish oil intake may actually increase the risk of high grade prostate cancer.

The precise link between omega-3 and different types of cancer remains unclear , but a number of studies have found no evidence to suggest that omega-3 either increases or reduces the risk of various types of cancer. People with low levels of omega-3 during pregnancy and while breastfeeding may be more susceptible to postpartum depression. The authors of a review concluded that taking fish oil supplements around this time may help reduce the risk of depression.

However, people should avoid eating fish that may be high in mercury, such as shark and king mackerel, during pregnancy. Some good alternative choices include canned light tuna, salmon, pollock, and catfish.

In addition to postpartum depression, some studies suggest that EPA and DHA could help treat various neuropsychiatric conditions. These include:. Some studies have suggested that omega-3 supplementation may help prevent cognitive decline, especially in older adults. However, their results are not conclusive, according to one review. Omega-3 fatty acids in fish oils may help prevent heart disease and stroke , according to the AHA. Specifically, omega-3 may help manage :.

A study found that people who took fish oil supplements for longer than 1 month had better cardiovascular function during mentally stressful tests. In , researchers noted that fish oil, due to its anti-inflammatory properties, appeared to help stabilize atherosclerotic lesions.

The AHA recommend eating fish, and especially oily fish, at least twice per week. They say that this may reduce the risk of cardiovascular disease. In a study , mice that received omega-3 supplements for 6 months appeared to have better retinal function and a lower risk of age-related vision loss than mice that did not receive the supplements. Optometrists often recommend taking omega-3 supplements to support eye health, even though scientific evidence does not always support their use for this purpose.

In some cases, eating a healthful diet may be more beneficial than taking supplements, according to some experts. In , for example, scientists who looked at the data of 4, people in Holland found that those who consumed fresh fruits and vegetables and 2 weekly servings of fish were less likely to develop age-related macular degeneration compared with those who did not. Some people use omega-3 supplements for dry eyes. In , however, a year-long study involving people with moderate-to-severe dry eyes found no evidence to suggest that taking supplements was more helpful than taking a placebo for this purpose.

Fish oil appears to contain almost no mercury, which can be a cause for concern in certain types of fish. While generally safe, getting too much fish oil can increase your risk of bleeding and might affect your immune response. It's not clear whether fish oil is safe for people who are allergic to seafood. Take fish oil supplements under a doctor's supervision. Taking high doses of fish oil supplements might increase the risk of bleeding and possibly increase the risk of stroke.

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