Many 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), according to the USDA National Nutrient Database. Other useful essential fatty acids in fish oil include alpha-linolenic acid or ALA and gamma-linolenic acid or GLA. 
Here is a brief on omega-3 fatty acids: There are three types of omega-3 fatty acids, namely alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). All three are important for the body.
A few of these health benefits include its ability to aid in weight loss and improve the skin. It has also shown positive implications in reducing the risk of heart disease, high cholesterol, mental health disorders, and inflammation, as well as others.
There are various types of fish that are good sources of oil; they 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 positive impact on most healthy adults, as it helps in weight loss, skincare, vision improvement, and other health issues.
|Serving Size :|
|Total lipid (fat) [g]||100|
|Fatty acids, total saturated [g]||21.29|
|Fatty acids, total monounsaturated [g]||56.56|
|Fatty acids, total polyunsaturated [g]||15.6|
|20:5 n-3 (EPA) [g]||6.27|
|22:5 n-3 (DPA) [g]||0.62|
|22:6 n-3 (DHA) [g]||4.21|
|Sources include : USDA |
Boosts Heart Health
According to the American Heart Association (AHA), clinical trials have shown that foods containing omega-3s are effective in reducing the incidence of cardiovascular diseases (CVD). Fish oil is a great source of omega-3 and therefore, may help individuals reduce the risk of heart diseases and heart arrhythmias. It also contributes to lowering elevated levels of LDL cholesterol (bad) and increases the level of HDL cholesterol (good). Omega 3 containing fish oil helps prevent the accumulation of triglycerides and also reduces the level of excess triglycerides. Preliminary research has shown that fish oil’s healthy components can be used to reduce the risk of atherosclerosis in coronary patients. Thus, regular usage of this oil may help avoid sudden cardiac death. As per the American Heart Association, these preliminary findings still need to be confirmed by further detailed research. 
Anti-obesity research conducted by the University of South Australia has shown that combining fish oil with exercise is more beneficial in reducing obesity than either one alone. Volunteers who were given fish oil in their diet and exercised showed greater weight loss as compared to those who did not regularly consume it and exercised. 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 thought that regular consumption of fish oil may aid in boosting your immune system, thereby enabling you to resist the occurrence of common ailments, such as cold, cough, and flu. The omega-3 fatty acids present in fish oil are thought to bolster the immune system by affecting the activity and amount of cytokines and eicosanoids present in our body. Some preliminary researchers published in the journal Animal Science have also studied the effect of bovine consuming fish and fish oil on their immune systems. They found that fish oil aided in the growth of the animals. Similar research conducted on mice at Taichung Veterans General Hospital in Taiwan also showed positive results.  
Fish oil may be an effective method in helping to reduce inflammation in the blood and tissues. Ideally, it is best to consume actual omega-3 containing fish products to reap all of the beneficial nutrient interactions. Fish oil is thought by some suffering from gastrointestinal disorders–such as Celiac disease, short bowel syndrome, and inflammatory bowel disease (IBD) including Crohn’s Disease and ulcerative colitis–to be effective in reducing inflammation.
Other inflammatory states including arthritis, rheumatism, Raynaud’s symptoms, may also benefit from this oil. It may help in reducing the need for large dosages of NSAIDs (non-steroidal anti-inflammatory drugs). The Royal Adelaide Hospital and the University of Newcastle, located in Australia, have reported that fish oil has shown positive effects in treating the symptoms of arthritis.  
While some research shows that regular consumption of fish oil supplements, tablets, pills, and capsules may be helpful to those who suffer from chronic inflammatory diseases, the jury is still out and more research is needed to confirm the benefits. 
May Relieve Depression & Anxiety
Due to the presence of omega-3 fatty acids, fish oil has been promoted for relieving depression, sadness, anxiety, restlessness, mental fatigue, stress, and low libido. Countries where fish is frequently eaten, have a lower incidence of depression. Multiple preliminary studies have shown Omega-3s as a promising natural solution for mood disorders; however, more research is underway to confirm these beneficial effects.
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. Findings of another research study suggest that fish consumption may be beneficial for women’s mental health and reduces the risk of developing depression in women. While a clear link can’t yet be established given the multiple compounds in fish, it is a good basis for suggesting that increasing omega-3 content may be beneficial for this population.  
May Reduce Risk & Progression of Neurodegenerative Disease
Research conducted at Louisiana State University has shown that fatty acids are connected to reducing the risk and slowing the progression of Alzheimer’s disease. Since fish oil is one of the best sources of essential fatty acids, including EPA and DHA, these may be a boon to those suffering. More research conducted at the University of California in Los Angeles validates the usefulness of fish oil as a possible remedy for the disease. The Alzheimer’s Association recommends consuming fish containing a higher content of omega-3 fatty acids to patients, as it may act as a defense against Alzheimer’s disease and dementia.  
Reduction in ADHD Symptoms
Fish oil may have the potential to reduce the symptoms of Attention Deficit Hyperactivity Disorder (ADHD) due to its high concentration of fatty acids. For children suffering from hyperactivity, dyslexia, short attention span, low concentration, or learning disorders, fish oil may be a part of the solution.
Preliminary research conducted at the University of South Australia and CSIRO has shown that when children suffering from ADHD were given doses of fish oil and evening primrose capsules for 15 weeks, they showed significant improvements in their behavior. More research is in the works to look more closely at these potential benefits. 
Furthermore, it is believed that fish oil is useful in the normal development of the brain, along with helping your child concentrate on their studies. It has also been found that when pregnant women are given regular doses of fish oil, their toddlers display enhanced hand-eye coordination. 
Fish oil is great for improving the condition of dry skin by making it look shiny and vibrant. It has been found by some to be useful in treating various skin problems such as eczema, psoriasis, itching, skin redness, and rashes. In terms of psoriasis, the EPA present in fish oil restricts the growth of pro-inflammatory agents by producing arachidonic acid.
Fish oil can also be applied topically to get relief from psoriasis; however, many find that it has a limited positive effect. Intravenous administration of fish oil, however, has been shown more effective. 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 thought to be a topical acne treatment. 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. 
The presence of EPA and DHA in fish oil may have some benefit in the case of ulcers caused by Nonsteroidal anti-inflammatory drugs (NSAIDs). 
Supports Healthy Pregnancy
Fish oil is beneficial for pregnant women as the DHA present in it helps in the development of the eyes and brain of the baby. Lack of seafood – and thus omega-3s were linked with premature births, low birth weight, and miscarriages. Research conducted in Denmark, which involved 8,729 pregnant women, concluded that a diet with low amounts of fish resulted in a higher risk of premature or preterm babies. 
It is also believed that women who do not have a sufficient intake of EPA and DHA in their diet suffer from depression after childbirth. Thus, it may be beneficial to consume fish oil either by consuming fish or taking fish oil supplements, tablets, capsules, or pills during pregnancy for the overall development of the child and the well-being of the mother. However, fish oil obtained from the liver of the fish, for example – cod liver oil – should not be consumed during pregnancy as cod liver oil is high in retinol and vitamin A, which are usually known to cause birth defects. If you are pregnant or trying to become pregnant, be sure to discuss options for getting fish oil with your OBGYN or primary doctor.
Fish oils rich in omega 3 fatty acids may help improve fertility and cell division in sperm. 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. More research is needed to clarify these results; however, given its slew of other positive benefits, it is still a benefit to consuming by most people.  
Fish oil is thought to help maintain good hair shine and luster because omega-3 has growth stimulating properties and provides nourishment to the follicles. A good supply of protein is also necessary for hair growth, and since most fish varieties are rich in protein, eating fish provides both of these hair health benefits.
Many people also like to feed fish oil to their pets, especially dogs and cats, as it promotes shiny and smooth hair.
Fish Oil and Lou Gehrig’s Disease
Fish oil is rich in omega-3 fatty acids, as mentioned. Recent research suggests that intake of a diet rich in omega-3 fatty acids may reduce or delay the onset of Amyotrophic lateral sclerosis (ALS) also known as Lou Gehrig’s disease. 
Fish Oil Side Effects
Even though fish oil has many benefits, excessive intake may cause allergy and side-effects. People who are allergic to seafood or fish, in particular, will experience effects like hives and swelling of face, lips, tongue, or throat. Consuming seafood or fish is not advised if you have a known allergy.
In the case of excess intake, one may also experience bad breath, stomach upset, loose stools, belching, nausea, or even more serious effects. Avoid consumption if allergic to fish. The American Heart Association recommends at least two servings of fatty fish weekly. 
Let us look at some of the side-effects in detail:
- Children: Excessive intake of fish oil by children may lead to allergic reactions like itchiness, sneezing, or a dry cough.
- Pregnant Women: Even though fish oil has many benefits for pregnant women, the mercury content found in certain seafood can be harmful to the memory, hearing abilities, cognitive skills, and vision of the baby.
Caution on Fish Oil Amount
An excessive dosage of fish oil can have adverse allergies and side effects on the body. Furthermore, fish oil can be problematic if you have certain conditions, so it is necessary to check with your doctor before consuming fish oil supplements. While consuming fish oil directly from fish is one thing, taking it in the form of concentrated dietary supplements like liquid, tablet, capsule, pill, or soft gels may pose an issue. Dietary supplements in the United States are not regulated by the government, so choosing a safe option is important.
Should We Replace Vegetable Oils with Fish Oil?
The short answer: not necessarily. There are many websites which advise people to stop eating vegetable oils and switch to fish oil to increase their intake of omega-3 fatty acids. Fish oil is a good source of omega-3 essential fatty acids and should be consumed, but that doesn’t necessarily mean that one should completely replace vegetable oils with fish oil.
Vegetable sources, including flaxseed oil, soybean oil, hemp oil, canola oil, walnut oil, rapeseed, perilla, chia, and tofu are rich in ALA. The human body can convert ALA to DHA and EPA, though there are certain limitations to this conversion. Additionally, eating a varied, healthy diet full of many different foods is most beneficial for health, as different foods provide robust nutrition that the body needs to function optimally.
How much fish oil is safe to consume?
Fish oil can be consumed in various ways such as capsules or can be included in daily meals. Research suggests that the dosage should not exceed three fish oil capsules per day. 1000mg of fish oil contains approximately 300mg omega-3 fatty acids. A daily intake of 3000mg or less is commonly thought of as being safe for the general population. Pregnant and lactating women can consume approximately 3200 mg per day.  
Fish Oil Purity
When purchasing fish oil, pay attention to quality. It is obtained from almost all fishes including – freshwater, farmed, ocean, deep sea, and shallow sea fish. All of these fish can be contaminated with toxic compounds such as mercury, arsenic, lead, forms of calcium, furans, dioxins, PCBs, and methylmercury, and can negatively affect the human body. Therefore, the fish oil used must be pure. Many companies sell ultra refined or distilled fish oil, but you should always check if the standards have been followed and research on the company or the product before adding it to your diet.
While fish oil has plenty of beneficial qualities, there is a lot of hype around its possible applications, and not all of them are accurate, so be wary when reading literature on this useful oil. Fish oil manufacturers have attempted to market it as a remedy for almost anything. We suggest that readers educate themselves fully before making an informed decision, rather than getting affected by both negative and positive propaganda about the beneficial applications of fish oil.
Fish Oil and Vitamins
Vitamin A and Vitamin D: Fish oil, especially the types obtained from fish livers like cod liver oil is a rich source of vitamin A and vitamin D. However, excessive dosage of cod liver oil can lead to vitamin toxicity, the accumulation of excessive vitamins in the body, which can cause serious side effects.
Vitamin E: Fish oil undergoes oxidation and can become rancid, leading to the formation of free radicals. The addition of antioxidants such as vitamin E to the oil can help prevent the formation of these free radicals. 
An excessive dosage of fish oil is thought to lead to decreased levels of vitamin E in the human body. This is another reason why adequate intake–but not excess–should be achieved.