The health benefits of fish oil include its ability to aid in weight loss and healthy pregnancy. It also promotes fertility and skin care (particularly for psoriasis and acne). It is beneficial in the treatment of various heart diseases, high cholesterol, depression, anxiety, ADHD, weak immune system, diabetes, inflammation, arthritis, IBD, Alzheimer’s disease, eye disorders, macular degeneration, and ulcers.
According to USDA National Nutrient Database, most of the health benefits of fish oil can be attributed to the presence of omega-3 essential fatty acids like docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in it.  Other useful essential fatty acids in fish oil include alpha-linolenic acid or ALA and gamma-linolenic acid or GLA.
The different types of fish which are a good source of oil include mackerel, lake trout, herring, sardines, swordfish, oysters, albacore tuna, bluefin tuna, yellowfin tuna, turbot, pilchards, anchovies, and salmon. The quality of fish oil greatly depends on the type of fish from which the oil is retrieved.
Health Benefits of Fish Oil
Fish oil has a great impact on our body as it helps in weight loss, skin care, vision improvement, and other health issues which are explained in detail below
According to the American Heart Association (AHA), clinical trials have shown that omega-3 is effective in reducing the incidence of cardiovascular diseases (CVD).  Fish oil is a great source of omega-3 and therefore, reduces the risk of heart diseases and heart arrhythmias. It also lowers the level of bad cholesterol (LDL) and increases the level of good cholesterol (HDL). Fish oil prevents the accumulation of triglycerides and also reduces the level of excess triglycerides. Preliminary research has shown that fish oil can be used to prevent atherosclerosis in coronary patients. Thus, fish oil is effective in preventing strokes and regular usage of fish oil can help avoid sudden cardiac death. As per the American Heart Association, these preliminary findings still need to be confirmed by a further detailed research.
Research conducted by Professor Peter Howe at the University of South Australia has shown that fish oil improves the efficacy of exercise in attempts to reduce weight.  Volunteers who were given fish oil in their diet showed greater weight loss as compared to those who did not regularly consume it. Fish oil contains omega-3 fatty acids, which help to promote weight loss, so a combination of physical workout and intake of this oil helps in reducing body fat significantly faster.
It is believed that regular consumption of fish oil aids in boosting your immune system, thereby enabling you to resist the occurrence of common diseases like colds, cough, and the flu. Omega-3 fatty acids present in fish oil bolster the immune system by affecting the activity and amount of cytokines and eicosanoids present in our body. Researchers have also studied the effect of a fish meal and fish oil on the immune system of pigs and found that fish oil aided in the growth of the animals. Similar research conducted on mice at Taichung Veterans General Hospital, Taiwan, also gave positive results.
Fish oil is beneficial to patients suffering from lupus, which is an autoimmune disease characterized by the immune system attacking its own organs and tissues. Studies have also shown fish oil to help in reducing fever, skin rashes, and fatigue.
Fish oil is effective in reducing inflammation in the blood and tissues. Regular consumption of fish oil supplements, tablets, pills, and capsules is helpful to those who suffer from chronic inflammatory diseases. Fish oil is effective in treating gastrointestinal disorders, Celiac disease, short bowel syndrome and inflammatory bowel disease (IBD) including Crohn’s Disease and ulcerative colitis, which are both typical disorders of the intestine. Patients suffering from Crohn’s disease often find it difficult to absorb vitamins, fats, and essential supplements. Fish oil supplements are an effective diet for such patients.
In terms of ulcerative colitis, fish oil prevents the accumulation of leukotriene in the colon. Research is also being conducted to increase the anti-inflammatory reputation of fish oil, particularly when combined with other dietary supplements and drugs.
Due to the presence of Omega-3 fatty acids, fish oil has been promoted for relieving depression, sadness, anxiety, restlessness, mental fatigue, stress, decreased sexual desire, suicidal tendencies, and other nervous disorders. Researchers at the Case Western Reserve University School of Medicine in Cleveland, Ohio, in their research publication titled “Fish Oils and Bipolar Disorder: A Promising but Untested Treatment”, state that fish oil can be useful in mood stabilization and the treatment of bipolar disorders. It is unsurprising, therefore, that countries where fish is frequently eaten, have a low incidence of depression. Similarly, research conducted on prisoners has shown that when prisoners were given seafood containing a higher amount of omega-3 fatty acids, there was a significant drop in the homicide rate and the frequency of violence.  Intake of fish is also a good remedy for depression. Findings of a research study suggest that fish consumption may be beneficial for women’s mental health and reduces the risk of developing depression in women
It is great for improving the condition of the dry skin by making it look shiny and vibrant. It is useful in treating various skin problems such as eczema, psoriasis, itching, skin redness, skin lesions, and rashes. In terms of psoriasis, the EPA present in fish oil restricts the growth of pro-inflammatory agents by producing arachidonic acid. Therefore, fish oil can also be applied topically to get relief from psoriasis.
Regular consumption of fish oil capsules helps in reducing moisture loss from the skin. It is also claimed by some people that the oil helps in preventing sunburn but the research behind that claim is not verified.
Fish oil is an effective treatment for acne. EPA present in the oil is known to inhibit androgen formation, which can affect the formation of sebum in the hair follicles, leading to acne.
Fish oils rich in omega 3 fatty acids help improve fertility and cell division. Preliminary research conducted on animals has shown that when males are fed a diet containing fish oil, the quality of the sperm is enhanced.  After ejaculation, the sperm has increased survival against lipid peroxidative attacks in the female genital tract, thereby increasing the chances of conception. On the other hand, similar animal studies have shown inhibition in the synthesis of prostaglandin E and prostaglandin F, which are produced in large quantities by human seminal vesicles.  The research, however, found no impact on the count and mobility of sperm.