1. May Support Heart Health
https://www.healthline.com/nutrition/13-benefits-of-fish-oil#section1
Heart disease is the leading cause of death worldwide (7Trusted Source).
Studies show that people who eat a lot of fish have much lower rates of heart disease (8Trusted Source, 9Trusted Source, 10Trusted Source).
Multiple risk factors for heart disease appear to be reduced by consumption of fish or fish oil. The benefits of fish oil for heart health include:
- Cholesterol levels: It can increase levels of “good” HDL cholesterol. However, it does not appear to reduce levels of “bad” LDL cholesterol (11Trusted Source, 12Trusted Source, 13Trusted Source, 14Trusted Source, 15Trusted Source, 16Trusted Source).
- Triglycerides: It can lower triglycerides by about 15–30% (16Trusted Source, 17Trusted Source, 18Trusted Source).
- Blood pressure: Even in small doses, it helps reduce blood pressure in people with elevated levels (19Trusted Source, 20Trusted Source, 21Trusted Source).
- Plaque: It may prevent the plaques that cause your arteries to harden, as well as make arterial plaques more stable and safer in those who already have them (22Trusted Source, 23Trusted Source, 24Trusted Source).
- Fatal arrhythmias: In people who are at risk, it may reduce fatal arrhythmia events. Arrhythmias are abnormal heart rhythms that can cause heart attacks in certain cases (25Trusted Source).
Although fish oil supplements can improve many of the risk factors for heart disease, there is no clear evidence that it can prevent heart attacks or strokes (26Trusted Source).
SUMMARYFish oil supplements may reduce some of the risks associated with heart disease. However, there is no clear evidence that it can prevent heart attacks or strokes.
2. May Help Treat Certain Mental Disorders
Your brain is made up of nearly 60% fat, and much of this fat is omega-3 fatty acids. Therefore, omega-3s are essential for normal brain function (27Trusted Source, 28Trusted Source).
In fact, some studies suggest that people with certain mental disorders have lower omega-3 blood levels (29Trusted Source, 30Trusted Source, 31Trusted Source).
Interestingly, research suggests that fish oil supplements can prevent the onset or improve the symptoms of some mental disorders. For example, it can reduce the chances of psychotic disorders in those who are at risk (32Trusted Source, 33Trusted Source).
In addition, supplementing with fish oil in high doses may reduce some symptoms of both schizophrenia and bipolar disorder (33Trusted Source, 34, 35Trusted Source, 36Trusted Source, 37Trusted Source, 38Trusted Source).
SUMMARYFish oil supplements may improve the symptoms of certain psychiatric disorders. This effect may be a result of increasing omega-3 fatty acid intake.
3. May Aid Weight Loss
Obesity is defined as having a body mass index (BMI) greater than 30. Globally, about 39% of adults are overweight, while 13% are obese. The numbers are even higher in high-income countries like the US (39Trusted Source).
Obesity can significantly increase your risk of other diseases, including heart disease, type 2 diabetes, and cancer (40Trusted Source, 41Trusted Source, 42Trusted Source).
Fish oil supplements may improve body composition and risk factors for heart disease in obese people (43Trusted Source, 44Trusted Source, 45Trusted Source).
Furthermore, some studies indicate that fish oil supplements, in combination with diet or exercise, can help you lose weight (43Trusted Source, 46Trusted Source).
However, not all studies found the same effect (47Trusted Source, 48Trusted Source).
One analysis of 21 studies notes that fish oil supplements didn’t significantly reduce weight in obese individuals but did reduce waist circumference and waist-to-hip ratio (49Trusted Source).
SUMMARYFish oil supplements may help reduce waist circumference, as well as aid weight loss when combined with diet or exercise.
4. May Support Eye Health
Like your brain, your eyes rely on omega-3 fats. Evidence shows that people who don’t get enough omega-3s have a greater risk of eye diseases (50Trusted Source, 51Trusted Source).
Furthermore, eye health begins to decline in old age, which can lead to age-related macular degeneration (AMD). Eating fish is linked to a reduced risk of AMD, but the results on fish oil supplements are less convincing (52Trusted Source, 53Trusted Source).
One study found that consuming a high dose of fish oil for 19 weeks improved vision in all AMD patients. However, this was a very small study (54).
Two larger studies examined the combined effect of omega-3s and other nutrients on AMD. One study showed a positive effect, while the other exhibited no effect. Therefore, the results are unclear (55Trusted Source, 56Trusted Source).
SUMMARYEating fish may help prevent eye diseases. However, it’s unclear whether fish oil supplements have this same effect.
5. May Reduce Inflammation
Inflammation is your immune system’s way of fighting infection and treating injuries.
However, chronic inflammation is associated with serious illnesses, such as obesity, diabetes, depression, and heart disease (57Trusted Source, 58Trusted Source, 59Trusted Source).
Reducing inflammation can help treat symptoms of these diseases.
Because fish oil has anti-inflammatory properties, it may help treat conditions involving chronic inflammation (60Trusted Source).
For example, in stressed and obese individuals, fish oil can reduce the production and gene expression of inflammatory molecules called cytokines (61Trusted Source, 62Trusted Source).
Moreover, fish oil supplements can significantly reduce joint pain, stiffness, and medication needs in people with rheumatoid arthritis, which causes painful joints (63Trusted Source, 64Trusted Source).
While inflammatory bowel disease (IBD) is also triggered by inflammation, there is no clear evidence to suggest whether fish oil improves its symptoms (65Trusted Source, 66Trusted Source).
SUMMARYFish oil has strong anti-inflammatory effects and can help reduce symptoms of inflammatory diseases, especially rheumatoid arthritis.
6. May Support Healthy Skin
Your skin is the largest organ in your body, and it contains a lot of omega-3 fatty acids (67Trusted Source).
Skin health can decline throughout your life, especially during old age or after too much sun exposure.
That said, there are a number of skin disorders that may benefit from fish oil supplements, including psoriasis and dermatitis (68Trusted Source, 69Trusted Source, 70Trusted Source).
SUMMARYYour skin can become damaged by aging or too much sun exposure. Fish oil supplements may help maintain healthy skin.
7. May Support Pregnancy and Early Life
Omega-3s are essential for early growth and development (71Trusted Source).
Therefore, it’s important for mothers to get enough omega-3s during pregnancy and while breastfeeding.
Fish oil supplements in pregnant and breastfeeding mothers may improve hand-eye coordination in infants. However, it’s unclear whether learning or IQ are improved (72Trusted Source, 73Trusted Source, 74Trusted Source, 75Trusted Source, 76Trusted Source).
Taking fish oil supplements during pregnancy and breastfeeding may also improve infant visual development and help reduce the risk of allergies (77Trusted Source, 78Trusted Source).
SUMMARYOmega-3 fatty acids are vital for an infant’s early growth and development. Fish oil supplements in mothers or infants may improve hand-eye coordination, although their effect on learning and IQ is unclear.
8. May Reduce Liver Fat
Your liver processes most of the fat in your body and can play a role in weight gain.
Liver disease is increasingly common — particularly non-alcoholic fatty liver disease (NAFLD), in which fat accumulates in your liver (79Trusted Source).
Fish oil supplements can improve liver function and inflammation, which may help reduce symptoms of NAFLD and the amount of fat in your liver (80Trusted Source, 81Trusted Source, 82Trusted Source, 83Trusted Source).
SUMMARYLiver disease is common in obese individuals. Fish oil supplements may help reduce fat in your liver and symptoms of non-alcoholic fatty liver disease.
9. May Improve Symptoms of Depression
Depression is expected to become the second-largest cause of illness by 2030 (84Trusted Source).
Interestingly, people with major depression appear to have lower blood levels of omega-3s (29Trusted Source, 85Trusted Source, 86Trusted Source).
Studies show that fish oil and omega-3 supplements may improve symptoms of depression (87Trusted Source, 88, 89).
Moreover, some studies have shown that oils rich in EPA help reduce depressive symptoms more than DHA (90Trusted Source, 91Trusted Source).
SUMMARYFish oil supplements — especially EPA-rich ones — may help improve symptoms of depression.
10. May Improve Attention and Hyperactivity in Children
A number of behavioral disorders in children, such as attention deficit hyperactivity disorder (ADHD), involve hyperactivity and inattention.
Given that omega-3s make up a significant proportion of the brain, getting enough of them may be important for preventing behavioral disorders in early life (92).
Fish oil supplements may improve perceived hyperactivity, inattention, impulsiveness, and aggression in children. This may benefit early life learning (93, 94, 95, 96Trusted Source).
SUMMARYBehavioral disorders in children can interfere with learning and development. Fish oil supplements have been shown to help reduce hyperactivity, inattention, and other negative behaviors.
11. May Help Prevent Symptoms of Mental Decline
As you age, your brain function slows down, and your risk of Alzheimer’s disease increases.
People who eat more fish tend to experience a slower decline in brain function in old age (97Trusted Source, 98Trusted Source, 99Trusted Source).
However, studies on fish oil supplements in older adults haven’t provided clear evidence that they can slow the decline of brain function (100Trusted Source, 101Trusted Source).
Nevertheless, some very small studies have shown that fish oil may improve memory in healthy, older adults (102Trusted Source, 103).
SUMMARYPeople who eat more fish have slower age-related mental decline. However, it’s unclear if fish oil supplements can prevent or improve mental decline in older adults.
12. May Improve Asthma Symptoms and Allergy Risk
Asthma, which can cause swelling in the lungs and shortness of breath, is becoming much more common in infants.
A number of studies show that fish oil may reduce asthma symptoms, especially in early life (104Trusted Source, 105Trusted Source, 106Trusted Source, 107Trusted Source).
In one review in nearly 100,000 people, a mother’s fish or omega-3 intake was found to reduce the risk of asthma in children by 24–29% (108Trusted Source).
Furthermore, fish oil supplements in pregnant mothers may reduce the risk of allergies in infants (109).
SUMMARYA higher intake of fish and fish oil during pregnancy may reduce the risk of childhood asthma and allergies.
13. May Improve Bone Health
During old age, bones can begin to lose their essential minerals, making them more likely to break. This can lead to conditions like osteoporosis and osteoarthritis.
Calcium and vitamin D are very important for bone health, but some studies suggest that omega-3 fatty acids can also be beneficial.
People with higher omega-3 intakes and blood levels may have better bone mineral density (BMD) (110Trusted Source, 111Trusted Source, 112Trusted Source).
However, it’s unclear whether fish oil supplements improve BMD (113Trusted Source, 114Trusted Source).
A number of small studies suggest that fish oil supplements reduce markers of bone breakdown, which may prevent bone disease (115Trusted Source).
SUMMARYHigher omega-3 intake is associated with higher bone density, which could help prevent bone disease. However, it’s unclear whether fish oil supplements are beneficial.
Overview
Fish oil is a dietary source of omega-3 fatty acids — substances your body needs for many functions, from muscle activity to cell growth.
Omega-3 fatty acids are derived from food. They can’t be manufactured in the body. Fish oil contains two omega-3s called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Dietary sources of DHA and EPA are fatty fish, such as salmon, mackerel and trout, and shellfish, such as mussels, oysters and crabs. Some nuts, seeds and vegetable oils contain another omega-3 called alpha-linolenic acid (ALA).
Fish oil supplements come in liquid, capsule and pill form.
People take fish oil to reduce the risk of heart attacks and strokes, to treat high triglycerides and high blood pressure, and to improve symptoms of rheumatoid arthritis.
Evidence
Research on the use of fish oil for specific conditions shows:
- Heart disease. Research shows that eating dietary sources of fish oil — such as tuna or salmon — twice a week is associated with a reduced risk of developing heart disease. Taking fish oil supplements for at least six months has been shown to reduce the risk of heart-related events (such as heart attack) and death in people who are at high risk of heart disease. Research also suggests that the risk of congestive heart failure is lower in older adults who have higher levels of EPA fatty acids.
- High blood pressure. Multiple studies report modest reductions in blood pressure in people who take fish oil supplements. There’s some evidence that this effect is greater for people with moderate to severe hypertension than those with mild hypertension.
- High triglycerides and cholesterol. There’s strong evidence that omega-3 fatty acids can significantly reduce blood triglyceride levels. There also appears to be a slight improvement in high-density lipoprotein (HDL, or “good”) cholesterol, although an increase in levels of low-density lipoprotein (LDL, or “bad”) cholesterol also was observed.
- Rheumatoid arthritis. Studies suggest fish oil supplements might help reduce pain, improve morning stiffness and relieve joint tenderness in people with rheumatoid arthritis. While relief is often modest, it might be enough to reduce the need for anti-inflammatory medications.
Our take
Generally safe
Omega-3 fatty acids are essential for good health. Try to get them from your diet by eating fish — broiled or baked, not fried. Fish oil supplements might be helpful if you have cardiovascular disease or an autoimmune disorder. Fish oil also appears to contain almost no mercury, which can be a cause for concern in certain types of fish. While generally safe, too much fish oil can increase your risk of bleeding and might suppress your immune response. Take fish oil supplements under a doctor’s supervision.
Safety and side effects
When taken as recommended, fish oil supplements are generally considered safe.
However, fish oil supplements can cause:
- A fishy aftertaste
- Bad breath
- Indigestion
- Nausea
- Loose stools
- Rash
Taking high doses of fish oil supplements might increase the risk of bleeding and possibly increase the risk of stroke.
It’s unclear whether people with fish or shellfish allergies can safely take fish oil.
Interactions
Possible interactions include:
- Anticoagulant and anti-platelet drugs, herbs and supplements. These types of drugs, herbs and supplements reduce blood clotting. It’s possible that taking fish oil supplements with them might increase the risk of bleeding.
- Blood pressure drugs, herbs and supplements. Taking fish oil supplements might slightly lower blood pressure. Taking these supplements with blood pressure drugs might increase the effects on blood pressure.
- Contraceptive drugs. Some contraceptive drugs might interfere with the effect fish oil typically has on triglycerides.
- Orlistat (Xenical, Alli). Taking fish oil with this weight-loss drug might decrease absorption of fish oil fatty acids. Consider taking the supplement and drug two hours apart.
- Vitamin E. Taking fish oil can reduce vitamin E levels.
https://www.mayoclinic.org/drugs-supplements-fish-oil/art-20364810
