Fish Oil

Fish Oil

What is it?

Fish oil can be obtained from eating fish or by taking supplements. Fish that are especially rich in the beneficial oils known as omega-3 fatty acids include mackerel, herring, tuna, salmon, cod liver, whale blubber, and seal blubber. Two of the most important omega-3 fatty acids contained in fish oil are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Make sure to see separate listings on EPA and DHA, as well as Cod Liver Oil, and Shark Liver Oil.

Certain types of fish oil are FDA approved to lower triglycerides levels.

Fish oil supplements have been tried for many other conditions. Fish oil is most often used for conditions related to the heart and blood system. Some people use fish oil to lower blood pressure, triglycerides and cholesterol levels. Fish oil has also been used for preventing heart disease or stroke, as well as for clogged arteries, chest pain, irregular heartbeat, bypass surgery, heart failure, rapid heartbeat, preventing blood clots, and high blood pressure after a heart transplant.

Fish oil is also used to for many kidney-related problems including kidney disease, kidney failure, and kidney complications related to diabetes, cirrhosis, Berger’s disease (IgA nephropathy), heart transplantation, or using the drug called cyclosporine.

Fish may have earned its reputation as “brain food” because some people eat fish to help with depression, bipolar disorder, psychosis, attention deficit-hyperactivity disorder (ADHD), Alzheimer’s disease, developmental coordination disorder, migraine headache, epilepsy, schizophrenia, post-traumatic stress disorder, and mental impairment.

Some people use fish oil for dry eyes, cataracts, glaucoma, and age-related macular degeneration (AMD), a very common condition in older people that can lead to serious sight problems. It is also used to prevent eye complications related to diabetes.

Fish oil is taken by mouth for stomach ulcers caused by Helicobacter pylori (H. pylori), inflammatory bowel disease, pancreatitis, an inherited disorder called phenylketonuria, allergy to salicylate, Crohn’s disease, Behcet’s syndrome, and Raynaud’s syndrome.

Women sometimes take fish oil to prevent painful periods; breast pain; and complications associated with pregnancy such as miscarriage (including that caused by a condition called antiphospholipid syndrome), high blood pressure late in pregnancy, early delivery, slow infant growth, and to promote infant development.

Fish oil is also taken by mouth for weight loss, exercise performance and muscle strength, muscle soreness after exercise, pneumonia, cancer, lung disease, seasonal allergies, chronic fatigue syndrome, and for preventing blood vessels from re-narrowing after surgery to widen them.

Fish oil is also used for diabetes, prediabetes, asthma, a movement and coordination disorder called dyspraxia, dyslexia, eczema, autism, obesity, weak bones (osteoporosis), rheumatoid arthritis (RA), osteoarthritis, psoriasis, an autoimmune disease called systemic lupus erythematosus (SLE), multiple sclerosis, HIV/AIDS, cystic fibrosis, gum disease, Lyme disease, sickle cell disease, and preventing weight loss caused by some cancer drugs.

Fish oil is used as a part of a specialized form of food that is given intravenously (by IV) for scaly and itchy skin (psoriasis), blood infection (sepsis), cystic fibrosis, pressure ulcers, and rheumatoid arthritis (RA). It is also used to prevent liver injury in people who are given food in the vein for long periods of time.

Fish oil is applied to the skin for psoriasis.

Natural Medicines rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for Fish Oil are as follows:

Effective for…

  • High triglycerides. Most research shows that fish oil can reduce triglyceride levels. The effects of fish oil appear to be the greatest in people who have very high triglyceride levels. The amount of fish oil consumed also seems to affect how much triglyceride levels are reduced. But fish oil might not lower triglyceride levels as effectively as drugs called fibrates. Certain fish oil preparations, including Lovaza , Omtryg, and Epanova, are approved as prescription drugs for treating very high triglyceride levels. These products are most often taken at a dose of 4 grams daily

. This provides about 3.5 grams of omega-3 fatty acids per day. While some non-prescription

  • fish oil supplements have also shown benefit in research, some experts discourage people from using these products. Often these products contain less omega-3 fatty acids than the prescription fish oil products. As a result, people would need to take as many as 12 capsules per day of fish oil supplements to get the same effect as prescription fish oil.

Likely Effective for…

  • Heart disease. Research suggests that eating fish can be effective for keeping people with healthy hearts free of heart disease. People who already have heart disease might also be able to lower their risk of dying from heart disease by eating fish. The picture is less clear for fish oil supplements. For people who already take heart medications such as a “statin” and those who already eat a decent amount of fish, adding on fish oil might not offer any additional benefit.

Possibly Effective for…

  • Preventing re-blockage of blood vessels after angioplasty, a procedure to open a closed blood vessel. Research suggests that fish oil decreases the rate of blood vessel re-blockage by up to 45% when given for at least 3 weeks before an angioplasty and continued for one month thereafter. But, when given for 2 weeks or less before angioplasty, it doesn’t seem to have any effect.
  • Miscarriage in pregnant women with an autoimmune disorder called antiphospholipid syndrome. Taking fish oil by mouth seems to prevent miscarriages and increase live birth rates in pregnant women with antiphospholipid syndrome.
  • Attention deficit-hyperactivity disorder (ADHD) in children. Early research shows that taking fish oil improves attention, mental function, and behavior in children 8-13 years-old with ADHD. Other research shows that taking a specific supplement containing fish oil and evening primrose oil (Eye Q, Novasel) improves mental function and behavior in children 7-12 years-old with ADHD.
  • Bipolar disorder. Taking fish oil along with conventional treatments for bipolar disorder seems to improve symptoms of depression but not mania in people with bipolar disorder.
  • Cancer-related weight loss. Taking a high dose of fish oil seems to slow weight loss in some cancer patients. Low doses of fish oil don’t seem to have this effect. Some researchers believe fish oil slows cancer-related weight loss by fighting depression and improving the mood of people with cancer.
  • Coronary artery bypass surgery. Taking fish oil seems to prevent coronary artery bypass grafts from re-closing following coronary artery bypass surgery.
  • High blood pressure caused by the drug cyclosporine. Cyclosporine is a medication that reduces the chance of organ rejection after an organ transplant. Taking fish oil seems to prevent high blood pressure caused by this drug.
  • Damage to the kidneys caused the drug cyclosporine. Cyclosporine is a medication that reduces the chance of organ rejection after an organ transplant. Taking fish oil seems to prevent kidney damage in people taking this drug. Fish oil also seems to improve kidney function during the recovery phase following the rejection of a transplanted organ in people taking cyclosporine.
  • Developmental coordination disorder (DCD). A combination of fish oil (80%) and evening primrose oil (20%) seems to improve reading, spelling, and behavior when given to children age 5-12 years with developmental coordination disorder. However, it does not seem to improve motor skills.
  • Menstrual pain (dysmenorrhea). Research shows that taking fish oil, alone or with vitamin B12, can improve painful periods and reduce the need for pain medications in women with menstrual pain.
  • Movement disorder in children (dyspraxia). Taking a fish oil product that also contains evening primrose oil, thyme oil, and vitamin E (Efalex, Efamol Ltd) seems to decrease movement disorders in children with dyspraxia.
  • Endometrial cancer. There is some evidence that women who regularly eat about two servings of fatty fish weekly have a reduced risk of developing endometrial cancer.
  • Heart failure. Higher intake of fish oil from foods has been linked with a reduced risk of heart failure. Eating 1-2 servings of non-fried fish per week is recommended. It’s too soon to know if taking fish oil supplements helps prevent heart failure. But early research shows that fish oil supplements might reduce adverse outcomes such as hospital admissions or death in people that already have heart failure.
  • Heart transplant. Taking fish oil seems to preserve kidney function and reduce the long-term rise in blood pressure after heart transplantation.
  • Abnormal cholesterol caused by HIV/AIDS treatment. Some research suggests that taking fish oil reduces triglyceride levels in people with abnormal cholesterol levels caused by HIV/AIDS treatment. Taking fish oil might also reduce total cholesterol levels in these people, although results are inconsistent.
  • High blood pressure. Fish oil seems to slightly lower blood pressure in people with moderate to very high blood pressure. Some types of fish oil might also reduce blood pressure in people with slightly high blood pressure, but results are inconsistent. Fish oil seems to add to the effects of some, but not all, blood pressure-lowering medications. However, it doesn’t seem to reduce blood pressure in people with uncontrolled blood pressure who are already taking blood pressure-lowering medications.
  • A certain kidney disease called IgA nephropathy. Some research shows that long-term but not short-term use of fish oil can slow the loss of kidney function in high-risk patients with IgA nephropathy. Fish oil might have greater effects when taken at higher doses. Also, it might be most effective in people with IgA nephropathy who have higher levels of protein in the urine.
  • Weak bones (osteoporosis). Research suggests that taking fish oil alone or together with calcium and evening primrose oil slows the rate of bone loss and increases bone density at the thigh bone (femur) and spine in elderly people with osteoporosis. But taking fish oil does not slow bone loss in older people with osteoarthritis in the knee but without weak bones.
  • Psoriasis. There is some evidence that administering fish oil intravenously (by IV) can decrease the severity of psoriasis symptoms. Also, applying fish oil to the skin also seems to improve some symptoms of psoriasis. But taking fish oil by mouth does not seem to have any effect on psoriasis.
  • Psychosis. Some research shows that taking a fish oil supplement might help prevent full psychotic illness from developing in teenagers and young adults with mild symptoms. These effects of fish oil have not been tested in older people.
  • Raynaud’s syndrome. There is some evidence that taking fish oil can improve cold tolerance in some people with the usual form of Raynaud’s syndrome. However, people with Raynaud’s syndrome caused by a condition called progressive systemic sclerosis do not seem to benefit from fish oil supplements.
  • Abnormal cholesterol following a kidney transplant. Early research suggests that taking fish oil alone or together with cholesterol-lowering drugs can improve cholesterol levels in people with abnormal cholesterol levels after a kidney transplant.
  • Rheumatoid arthritis (RA). Taking fish oil by mouth, alone or together with the drug naproxen (Naprosyn), seems to help improve symptoms of RA. People who take fish oil can sometimes reduce their use of pain medications. Also, administering fish oil intravenously (by IV) reduces swollen and tender joints in people with RA.
  • Stroke. Moderate fish consumption (once or twice weekly) seems to lower the risk of having a stroke by as much as 27%. However, very high fish consumption (more than 46 grams of fish per day) seems to increase stroke risk, perhaps even double it. Eating fish does not lower stroke risk in people who are already taking aspirin for prevention.

Possibly Ineffective for…

  • Chest pain (angina). Research suggests that taking fish oil supplements does not reduce the risk of death or improve heart health in people with chest pain. Some evidence even suggests that fish oil supplements might actually increase the risk of heart-related death in people with chest pain.
  • Hardening of the arteries (atherosclerosis). Some research shows that taking fish oil supplements might slightly reduce the progression of atherosclerosis. But most research shows that fish oil doesn’t slow the progression or improve symptoms of atherosclerosis.
  • Scaly, itchy skin (eczema). Research shows that fish oil does not improve eczema. Most research also shows that taking fish oil during pregnancy doesn’t PREVENT eczema in the child. Giving fish oil to an infant also doesn’t seem to prevent eczema in children. But children who eat fish at least once weekly from the age of 1-2 years seem to have a lower risk of developing eczema.
  • Irregular heartbeat (atrial fibrillation). Some research suggests that people who eat fish five or more times weekly have a reduced risk of irregular heartbeat. But most research suggests that eating fatty fish or taking fish oil supplements does not reduce the risk of irregular heartbeat.
  • Brain disorder due to blood blow problems (cerebrovascular disease). Some early research suggests that eating fish reduces the risk of cerebrovascular disease. But higher quality research suggests that taking fish oil does not have this effect.
  • Liver scarring (cirrhosis). Taking fish oil by mouth does not seem to improve kidney problems associated with liver scarring caused by advanced liver disease.
  • Leg pain due to blood flow problems (claudication). Taking fish oil by mouth does not appear to improve walking distance in people with leg pain due to blow flow problems.
  • Mental function. Most research shows that taking fish oil supplements does not improve mental function in older people , young adults , or children.
  • Gum disease (gingivitis). Taking fish oil does not seem to improve gingivitis.
  • Helicobacter pylori (H. pylori) infection. Taking fish oil by mouth does not seem to improve H. pylori infections when compared to standard medications.
  • HIV/AIDS. Some evidence shows that eating food bars containing fish oil does not increase CD4 cell counts in people with human immunodeficiency virus (HIV). Also, taken formula containing fish oil doesn’t seem to reduce the amount of HIV in the blood.
  • Breast pain (mastalgia). Taking fish oil does not appear to reduce long-term breast pain.
  • Migraine headaches. Taking fish oil by mouth does not appear to decrease the number or severity of migraine headaches.
  • Osteoarthritis. People with osteoarthritis who take low doses of fish oil seem to have less pain and better function compared to those taking high doses of fish oil. This result is somewhat unexpected and might be due to a “placebo effect.” Adding fish oil to glucosamine doesn’t further reduce pain or stiffness compared to taking glucosamine alone.
  • Pneumonia. Population research shows no relationship between fish consumption and the risk of developing pneumonia.
  • Kidney transplant. Research shows that taking fish oil doesn’t help people live longer after a kidney transplant. It also doesn’t seem to prevent the body from rejecting the transplant.
  • Blood infection (sepsis). Research suggests that administering fish oil intravenously (by IV) does not improve survival or reduce brain injury in people with sepsis.
  • Abnormal rapid heart rhythms (ventricular arrhythmias). Population research suggests that eating a lot of fish has no effect on the risk for abnormal rapid heart rhythms. Clinical research is inconsistent. Some research shows that taking fish oil daily does not affect the risk for abnormal heart rhythms. But other research shows that taking fish oil for 11 months delays the development of the condition. However, overall, taking fish oil does not seem to reduce the risk of death in people with abnormal rapid heart rhythms.

Likely Ineffective for…

  • Diabetes. Taking fish oil does not lower blood sugar in people with type 2 diabetes. However, fish oil can provide some other benefits for people with diabetes, such as lowering blood fats called triglycerides.

Insufficient Evidence to Rate Effectiveness for…

  • Age-related vision loss. There is some evidence that people who eat fish more than once weekly have a reduced risk of developing age-related vision loss. But, clinical research shows that taking fish oil by mouth for up to 5 years does not prevent vision loss.
  • Age-related muscle loss. The effects of fish oil on muscle in elderly people are not clear. Some research shows that taking fish oil along with strength training increases muscle gain better than strength training alone. But other research shows no benefit.
  • Seasonal allergies (hayfever). Early research suggests that mothers who take fish oil supplements during the late stages of pregnancy may lower the occurrence of allergies in their children. But other research suggests that fish oil does not reduce the development of allergies in children when taken by the mother during pregnancy.
  • Alzheimer’s disease. There is some early evidence that fish oil might help prevent Alzheimer’s disease. However, it does not seem to help prevent a decline in thinking skills for most people who have already been diagnosed with Alzheimer’s disease.
  • Asthma. Some research suggests that fish oil supplements might help TREAT some asthma symptoms. But results aren’t consistent. Some research shows that taking fish oil improves breathing and reduces the need for medication. Other research shows that fish oil does not reduce the severity of asthma is children. Fish oil might help PREVENT asthma in young children when taken by the mother while pregnant. But fish oil does not seem to provide any benefits when taken by the mother while breastfeeding or by the infant. Overall, research suggests that fish oil does not help TREAT eczema once it has developed.
  • Autism. One small study shows that taking fish oil might reduce hyperactivity in children with autism. But this study had flaws. Other research shows that taking fish oil doesn’t reduce hyperactivity.
  • Cancer. Research on the effects of fish oil in preventing cancer has produced conflicting results. Some population research suggests that eating fish or having higher blood levels of omega-3 fatty acids from fish oil is linked to a lower risk of different cancers, including oral cancer, pharyngeal cancer, esophageal cancer, colon cancer, rectal cancer, breast cancer, ovarian cancer, and prostate cancer. But other research suggests that eating fish does not reduce the risk of cancer.
  • Heart disease. Most research shows that taking fish oil supplements doesn’t prevent heart disease or reduce the chance of heart-related events in people with heart disease. Getting fish oil from the diet might be beneficial. But benefits are probably modest at best. People should still eat fish and other foods that provide fish oil, though. These foods make up part of a healthy diet.
  • Cataracts. There is some early evidence that eating fish three times weekly can slightly lower the risk of developing cataracts.
  • Chronic fatigue syndrome (CFS). There is some conflicting evidence about the use of a specific product (Efamol Marine) that combines fish oil and evening primrose oil to reduce the symptoms CFS.
  • Chronic kidney disease. Early evidence shows that fish oil might benefit some people with chronic kidney disease who are receiving dialysis treatments. But it’s not clear if fish oil helps people with poor kidney function who are otherwise healthy.
  • Abnormal cholesterol caused by clozapine. Clozapine is a drug used to treat schizophrenia. Early evidence suggests that taking fish oil reduces triglyceride levels, but increases total cholesterol and low-density lipoprotein (LDL or “bad”) cholesterol, in people with abnormal cholesterol levels due to taking clozapine.
  • Colorectal cancer. Some early research suggests that taking fish oil during chemotherapy might slow the progression of tumors in people with colorectal cancer.
  • Thinking problems (cognitive impairment). Some research suggests that taking fish oil by mouth daily for 12 months might improve memory in people with reduced mental function.
  • Crohn’s disease. Research into the effects of fish oil on Crohn’s disease has produced conflicting results. Some research shows that taking a specific fish oil product (Purepa, Tillotts Pharma) can reduce the relapse of Crohn’s disease for people who have recovered. However, other research shows that fish oil does not have this effect.
  • Cystic fibrosis. Early research suggests that taking fish oil by mouth can improve lung function in people with cystic fibrosis. However, administering fish oil intravenously (IV) does not have this effect.
  • Memory loss (dementia). Some early research suggests that eating fish at least once per week reduces the risk of developing dementia. Other research suggests there is no link between fish consumption and the risk of dementia.
  • Depression. There is inconsistent evidence on the effect of taking fish oil for depression. Some research shows that taking fish oil along with an antidepressant might help improve symptoms in some people. Other research shows that taking fish oil does not improve depression symptoms. The conflicting results may be due to the amount of EPA and DHA in the supplement or the severity of depression before treatment.
  • Kidney damage in people with diabetes (diabetic nephropathy). Evidence suggests that taking fish oil does not improve kidney function in people with diabetic nephropathy.
  • Eye damage in people with diabetes (diabetic retinopathy). Higher intake of fish oil from the diet has been linked to a reduced risk of eye damage in people with diabetes.
  • Dry eye. Higher intake of fish oil from the diet has been linked to a lower risk of dry eye in women. But the effects of fish oil in people with dry eye are inconsistent. Some research shows that fish oil reduces dry eye symptoms such as pain, blurred vision, and sensitivity. But fish oil doesn’t seem to improve other signs and symptoms of dry eye such as tear production and damage to the surface of the eye. Taking fish oil also doesn’t improve signs and symptoms of dry eye when used with other dry eye treatments.
  • Dyslexia. Taking fish oil by mouth seems to improve night vision in children with dyslexia.
  • Abnormal cholesterol or fat levels in the blood (dyslipidemia). There is conflicting data about the effects of fish oil on blood  fats in people with abnormal blood fat levels. Research shows that eating two servings of fish per week can lower cholesterol and blood fats in people with high cholesterol. Taking fish oil supplements also seems to improve levels of triglycerides and certain other blood fats in people with diabetes and abnormal blood fat levels. But most research shows that taking fish oil supplements does not improve cholesterol levels in people with abnormal or high cholesterol levels. In fact, taking fish oil supplements might actually increase low-density lipoprotein (LDL or “bad”) cholesterol levels in these people.
  • Advanced kidney disease (end stage renal disease). Some evidence suggests that taking fish oil reduces markers of swelling (inflammation) in people with advanced kidney disease.
  • Epilepsy. Research suggests that taking omega-3 fatty acids from fish oil by mouth daily for 10 weeks reduces seizures in people with epilepsy that is resistant to drugs.
  • Muscle soreness due to exercise. Some research shows that taking fish oil by mouth daily for 1-6 months before and during exercise does not prevent muscle soreness in the elbow or the knee when contracted. But other research suggests that taking fish oil improves soreness from knee extension exercises.
  • Exercise performance. Some evidence suggests that taking fish oil can improve lung function in athletes. But other evidence suggests that taking fish oil does not improve endurance, recovery, heart rate, or exercise duration.
  • Food allergies. Taking fish oil during pregnancy seems to reduce the risk of egg allergies in the infant. But it doesn’t reduce the risk of other food allergies such as milk or peanut allergies in the infant.
  • Preventing blockage of grafts used in kidney dialysis. Taking fish oil seems to help prevent blood clot formation in hemodialysis grafts. It might also help the grafts work longer. But more research is needed to know which dose of fish oil is best.
  • Prediabetes. Taking fish oil does not seem to
  • improve blood sugar in people with prediabetes. But it might help prevent prediabetes from advancing to type 2 diabetes.
  • Infant development. The strongest research shows that taking fish oil supplements during pregnancy or breastfeeding does not improve mental development of the infant. Feeding infants formula with fish oil appears to improve the infant’s vision but not mental development.
  • Multiple sclerosis. Taking a specific fish oil product (MaxEPA) does not appear to improve the duration, frequency, or severity of relapses in patients with multiple sclerosis.
  • A liver disease called nonalcoholic fatty liver disease (NAFLD). Limited research shows that fish oil might be beneficial for NAFLD in adults and children.
  • Weight loss. Most research shows that taking fish oil does not improve weight loss . But eating fish as part of a reduced-calorie diet seems to help.
  • Sores in the mouth. Taking fish oil seems to reduce the severity and pain of sores in the mouth from cancer drugs.
  • Swelling of the pancreas (pancreatitis). Evidence suggests that feeding intravenously (IV) with nutrition that has been fortified with fish oil reduces the number of days of kidney replacement therapy needed by people with severe inflammation of the pancreas.
  • Phenylketonuria (PKU). Some evidence suggests that taking fish oil supplements improves motor skills, coordination, and vision in children with a rare genetic disorder called phenylketonuria.
  • Post-traumatic stress disorder (PTSD). Some early research shows that adding supplements containing omega-3 fatty acids from fish oil to psychoeducation does not provide any further benefits to people with PTSD.
  • Pregnancy complications. Taking fish oil or eating seafood during pregnancy might help prevent premature delivery. But conflicting results exist. Fish oil does not seem to prevent high blood pressure during pregnancy, stillbirth, or other pregnancy complications.
  • Prematurity. Baby formula that has been fortified with fatty acids from fish oil and borage oil seems to improve growth and nervous system development in premature infants, especially boys.
  • Bed sores (pressure ulcers). Early research suggests that supplementing either a feeding tube or IV with fish oil for 28 days might slow the progression of pressure ulcers.
  • Salicylate intolerance. Some early research suggests that taking fish oil might improve symptoms of salicylate intolerance, such as asthma attacks and itching.
  • Schizophrenia. Fish oil might improve symptoms such as aggression in people with schizophrenia . But not all research agrees.
  • Blood infection (sepsis). Giving fish oil as part of a nutrition plan to patients with sepsis might reduce the need for mechanical breathing and shorten the stay in the intensive care unit of the hospital. But giving fish oil does not improve survival or reduce the risk of brain injury or delirium in people with sepsis.
  • Sickle cell disease. Early research suggests that taking fish oil can reduce severe pain episodes in people with sickle cell disease.
  • Stroke. Taking fish oil as a supplement doesn’t seem to prevent stroke. The effect that eating fish oil in the diet has on stroke risk is controversial. Eating fish once or twice weekly seems to lower the risk of having a stroke by as much as 27%. But eating very high amounts of fish (more than 46 grams of fish per day) seems to increase stroke risk. And eating fish does not lower stroke risk in people who are already taking aspirin for prevention.
  • Systemic lupus erythematosus (SLE). Some early studies suggest that fish oil helps improve symptoms of SLE, while other studies show no effect.
  • Inflammatory bowel disease (ulcerative colitis). Research studies into the effects of fish oil for treating ulcerative colitis show conflicting results.
  • Upper airway infection. Drinking a beverage containing fish oil, vitamin D, and protein does not seem to reduce upper airway infection in athletes.
  • Behcet’s syndrome.
  • Glaucoma.
  • Other conditions.

More evidence is needed to rate fish oil for these uses.

A lot of the benefit of fish oil seems to come from the omega-3 fatty acids that it contains. Interestingly, the body does not produce its own omega-3 fatty acids. Nor can the body make omega-3 fatty acids from omega-6 fatty acids, which are common in the Western diet. A lot of research has been done on EPA and DHA, two types of omega-3 acids that are often included in fish oil supplements.

Omega-3 fatty acids reduce pain and swelling. This may explain why fish oil is likely effective for psoriasis and dry eyes. These fatty acids also prevent the blood from clotting easily. This might explain why fish oil is helpful for some heart conditions.

Fish oil is LIKELY SAFE for most people when taken by mouth in low doses (3 grams or less per day). There are some safety concerns when fish oil is taken in high doses. Taking more than 3 grams per day might keep blood from clotting and can increase the chance of bleeding.

High doses of fish oil might also reduce the immune system’s activity, reducing the body’s ability to fight infection. This is a special concern for people taking medications to reduce their immune system’s activity (organ transplant patients, for example) and the elderly.

Only take high doses of fish oil while under medical supervision.

Fish oil can cause side effects including belching, bad breath, heartburn, nausea, loose stools, rash, and nosebleeds. Taking fish oil supplements with meals or freezing them can often decrease these side effects.

Fish oil is POSSIBLY SAFE when injected intravenously (by IV) in the short-term. Fish oil or omega-3 fatty acid solutions have been safely used for 1 to 4 weeks.

Consuming large amounts of fish oil from some DIETARY sources is POSSIBLY UNSAFE. Some fish meats (especially shark, king mackerel, and farm-raised salmon) can be contaminated with mercury and other industrial and environmental chemicals. Fish oil supplements typically do not contain these contaminants.

Special Precautions & Warnings:

Children: Fish oil is POSSIBLY SAFE when taken by mouth appropriately. Fish oil has been used safely through feeding tubes in infants for up to 9 months. But young children should not eat more than two ounces of fish per week. Fish oil is also POSSIBLY SAFE when given in the vein by a health care professional to infants who cannot take food by mouth. Fish oil is POSSIBLY UNSAFE when consumed from dietary sources in large amounts. Fatty fish contain toxins such as mercury. Eating contaminated fish frequently can cause brain damage, mental retardation, blindness and seizures in children. 

Pregnancy and breast-feeding: Fish oil is LIKELY SAFE when taken by mouth appropriately. Taking fish oil during pregnancy does not seem to affect the fetus or baby while breast-feeding. Women who are pregnant or who may become pregnant, and nursing mothers should avoid shark, swordfish, king mackerel, and tilefish (also called golden bass or golden snapper), as these may contain high levels of mercury. Limit consumption of other fish to 12 ounces/week (about 3 to 4 servings/week). Fish oil is POSSIBLY UNSAFE when dietary sources are consumed in large amounts. Fatty fish contain toxins such as mercury.

Bipolar disorder: Taking fish oil might increase some of the symptoms of this condition.

Liver disease: Fish oil might increase the risk of bleeding in people with liver scarring due to liver disease.

Depression: Taking fish oil might increase some of the symptoms of this condition.

Diabetes: There is some concern that taking high doses of fish oil might make the control of blood sugar more difficult.

Familial adenomatous polyposis: There is some concern that fish oil might further increase the risk of getting cancer in people with this condition.

High blood pressure: Fish oil can lower blood pressure and might cause blood pressure to drop too low in people who are being treated with blood pressure-lowering medications.

HIV/AIDS and other conditions in which the immune system response is lowered: Higher doses of fish oil can lower the body’s immune system response. This could be a problem for people whose immune system is already weak.

An implanted defibrillator (a surgically placed device to prevent irregular heartbeat): Some, but not all, research suggests that fish oil might increase the risk of irregular heartbeat in patients with an implanted defibrillator. Stay on the safe side by avoiding fish oil supplements.

Fish or seafood allergy: Some people who are allergic to seafood such as fish might also be allergic to fish oil supplements. There is no reliable information showing how likely people with seafood allergy are to have an allergic reaction to fish oil. Until more is known, advise patients allergic to seafood to avoid or use fish oil supplements cautiously.

Birth control pills (Contraceptive drugs)

Interaction Rating = Moderate Be cautious with this combination
Talk with your health provider.

Birth control pills might interfere with the triglyceride-lowering effects of fish oil.

Some of these drugs include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

Medication for cancer called platinum agents

Interaction Rating = Minor Be watchful with this combination
Talk with your health provider.

Some fish oil products contain small amounts of a fatty acid that is believed to stop chemotherapy drugs called platinum agents from working. However, the amount of this fatty acid in most fish oil products is probably too low to be a concern. Until more is known, you do not need to stop taking fish oil if you are also taking platinum agents.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Using fish oil with drugs that lower blood pressure may increase the effects of these drugs and may lower blood pressure too much.

Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), amlodipine (Norvasc), hydrochlorothiazide (HydroDIURIL), furosemide (Lasix), and many others.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating = Minor Be watchful with this combination.
Talk with your health provider.

Using fish oil with medications that slow clotting has been thought to increase the risk of bleeding. However, most research shows that fish oil does not increase bleeding. Until more is known, be watchful if combining with medications that slow blood clotting.

Some of these drugs include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), dipyridamole (Persantine), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.

Orlistat (Xenical, Alli)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Orlistat (Xenical, Alli) might keep the beneficial fatty acids in fish oil from being absorbed by the body. Taking fish oil and orlistat (Xenical, Alli) at least 2 hours apart may keep this from happening.

Warfarin (Coumadin)

Interaction Rating = Minor Be watchful with this combination.
Talk with your health provider.

Warfarin (Coumadin) is used to slow blood clotting. Fish oil also might slow blood clotting. Taking fish oil with warfarin might slow blood clotting too much and increase the risk of bleeding. However, conflicting results suggests that fish oil does not increase the effects of warfarin. Until more is known, use cautiously in combination with warfarin. Have your blood checked regularly, as your dose of warfarin (Coumadin) might need to be changed.

Herbs and supplements that lower blood pressure (hypotensive herbs and supplements)

Fish oil might lower blood pressure. It has the potential to add to blood pressure lowering effects of other herbs and supplements that also lower blood pressure. Other herbs and supplements that can lower blood pressure include andrographis, casein peptides, cat’s claw, coenzyme Q-10, L-arginine, lycium, stinging nettle, theanine, and others.

Herbs and supplements that might slow blood clotting

High doses of fish oil have been thought to slow blood clotting. However, most research shows that fish oil does not increase bleeding. Until more is known, be watchful if combining with herbs and supplements that might slow blood clotting. These herbs include angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, red clover, turmeric, willow, and others.

Vitamin E

Fish oil can reduce vitamin E levels. Researchers aren’t sure whether fish oil keeps vitamin E from being absorbed from food or whether it causes the body to use up vitamin E faster than it should.

There are no known interactions with foods.

Aceite de Pescado, Acides Gras Oméga-3, Acides Gras Oméga 3, Acides Gras Oméga 3 Sous Forme Ester Éthylique, Acides Gras N-3, Acides Gras Polyinsaturés N-3, Acides Gras W3, ACPI, EPA/DHA Ethyl Ester, Ester Éthylique de l’AEP/ADH, Fish Body Oil, Herring Oil, Huile de Foie de Morue, Huile de Hareng, Huile de Menhaden, Huile de Poisson, Huile de Saumon, Huile de Thon, Huile Lipidique Marine, Huile Marine, Huiles Marines, Lipides Marins, Marine Lipid Concentrate, Marine Fish Oil, Marine Lipid Oil, Marine Lipids, Marine Oil, Marine Oils, Marine Triglyceride, Menhaden Oil, N-3 Fatty Acids, N3-polyunsaturated Fatty Acids, Omega 3, Oméga 3, Omega-3, Oméga-3, Omega-3 Fatty Acid Ethyl Ester, Omega-3 Fatty Acids, Omega 3 Fatty Acids, Omega-3 Marine Triglycerides, PUFA, Salmon Oil, Triglycérides Marins, Tuna Fish Oil, Tuna Oil, W-3 Fatty Acids.


 

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