Is Fish Oil, Hailed as a Miracle Supplement, Truly Necessary?


When you open social media to search for health products, you can’t avoid this thing – fish oil.

Elders say it can protect blood vessels, parenting circles spread that it can promote brain development, fitness enthusiasts and white-collar workers also say it can anti-inflammatory, help metabolism and they have started eating it.


On one side, there is an overwhelming amount of praise, but on the other side, there are various warnings, many people also say “supplementing in vain”, “excess has risks”, the information is mixed, and ordinary people really find it difficult to discern.


Today, let’s dig into it, how much real material does this fish oil have? Is it really necessary to supplement?



What is the relationship between Omega-3, EPA, DHA, and fish oil?



To understand whether fish oil is necessary, we must first clarify the relationship between these substances.



  • Fish oil: Refers to the lipids extracted from the tissues of deep-sea fish, which are carriers of nutrients.


  • Omega-3 (n-3/ω-3) : This is the core component of fish oil that really works , belongs to a class of polyunsaturated fatty acids, which are essential for the human body, but the human body can hardly synthesize them on its own and need to be ingested through diet. There are three important members in the Omega-3 family: ALA, DHA, and EPA.

  • ALA (α-linolenic acid) : Is the parent molecule of the Omega-3 family (precursor) , mainly found in plant-based foods such as flaxseed oil, chia seeds, and walnuts. In the human body, ALA can be converted into EPA+DHA through a series of reactions, but the efficiency is very low.


  • EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) : Are considered conditionally essential fatty acids. Although the human body can convert ALA into EPA and DHA, the conversion efficiency is very low. This means that relying solely on eating nuts or flaxseed oil to meet the brain and blood vessel’s demand for long-chain Omega-3 is difficult, and it is necessary to obtain it through eating deep-sea fish (salmon, sardines, trout) , fish oil, or algae.



Are these online effects true?


The EPA and DHA in fish oil, as fatty acids needed by the human body, are responsible for many physiological activities of the body, DHA supports brain development and vision, while EPA is responsible for blood lipid reduction, anti-inflammatory, and cardiovascular protection.


However, in a lot of publicity, fish oil has gone from “having a certain effect” to “a panacea that everyone needs”. Let’s see what the evidence and research say:


Cardiovascular Protection

Very useful for patients with hyperlipidemia and heart disease, and conditional in preventing accidents.

Reducing triglycerides: The scientific community recognizes that a daily intake of 2-4 grams of high-dose Omega-3 can reduce triglyceride levels by 25% to 40%. It works by inhibiting the liver’s production of fat and accelerating the clearance of fat from the blood.

Benefits for high-risk groups: The famous REDUCE-IT study proved that for high-risk groups who already have cardiovascular diseases or diabetes, taking 4 grams of high-purity EPA preparation daily can reduce the risk of major adverse cardiovascular events by 25%.

Controversial: Large-scale trials such as VITAL and ASCEND found that for originally healthy, non-history individuals, the effect is not significant in reducing major cardiovascular accidents (such as stroke, cardiovascular death).

Brain Health

Helps maintain cognitive function, delays brain atrophy, and aids in improving major depression.

Definite: It is the basic structure of the brain. 14% of the brain’s gray matter is DHA, which determines the smoothness of neural signal transmission.

Possible: For the elderly with mild cognitive impairment, the elderly with higher levels of Omega-3, supplementing B vitamins can slow down the rate of brain atrophy, but no such benefits are shown in populations with lower levels of Omega-3 fatty acids.

Limitations: For patients who have entered the middle and late stages of Alzheimer’s disease, there is basically no reversing effect.

Pregnancy and Infant Development

Reduces the risk of premature birth and promotes child development.

Reducing the risk of premature birth: Clinically proven, women with lower Omega-3 levels, supplementing 600 ~ 1000mg of DHA daily during pregnancy can reduce the risk of early premature birth (<34 weeks) by 50% to 65%.

Promoting child development: Adding DHA to infant formula has a definite help in improving visual acuity.

Anti-inflammatory and Mental Health

Significant auxiliary effects.

Inflammation control: It has a significant effect on shortening morning stiffness time for patients with rheumatoid arthritis and can slightly relieve joint pain.

Mood regulation: Fish oil containing a high proportion of EPA (>60%) has a significant auxiliary effect on major depression.


In addition to the above, increasing the intake of fatty fish also has certain benefits for the eyes (age-related macular degeneration) , metabolism (non-alcoholic fatty liver disease, insulin resistance) , anti-aging, and cancer.



Do I need to take fish oil?



First, it is important to clarify that the ultimate goal of taking fish oil is to supplement EPA+DHA in Omega-3.


These components can be obtained by eating deep-sea fish, so food supplementation is preferred!


Specifically, you can refer to the recommendations of our country’s dietary guidelines and FDA:


  • China Residents’ Dietary Guidelines 2022 recommends: It is best to eat fish twice a week or 300 ~ 500 grams.


  • FDA recommends: Based on a 2000 calorie diet standard, at least 8 ounces (226.8 grams) of seafood per week.


But if you really don’t like to eat fish and find it troublesome, unable to obtain enough Omega-3 by eating fish, it is still recommended to supplement fish oil (vegetarians supplement algal oil) , to meet our body’s demand for EPA and DHA.



How to take fish oil? How much?



Different international organizations and national agencies have different recommendations for Omega-3 intake.


The consensus of most agencies is it is recommended that adults consume 250mg or more of EPA+DHA daily, and pregnant and lactating women are usually advised to add an additional 100-200mg of DHA on top of the base amount.


Different agencies also have different safety limits for fish oil intake, but for the general healthy population, a daily intake of 250mg to 1g of fish oil is very safe and sufficient.


  • China Residents’ Dietary Nutrients 2023 EPA+DHA acceptable range: 250 ~ 2000mg.

  • FAO: 250 ~ 2000mg/day EPA+DHA.

  • EFSA: 250mg/day of EPA+DHA.

  • SACN: at least 450mg/day.

  • AFSSA: 500mg/day (DHA should account for 250 mg/day).

  • Pregnant and lactating women: It is usually recommended to add an additional 100-200mg of DHA on top of the base amount. Some agencies also recommend a higher dose of EPA+DHA (1g/d), especially DHA (500 ~ 600mg/d).

Image source: See reference 4.



What should be considered when choosing fish oil?



1. Actual content

When purchasing, do not only look at the “total fish oil content” marked on the packaging, but check the specific grams of EPA and DHA per serving in the nutritional table. At least 250mg of EPA+DHA.


2. Look at the type of fish

Choose raw materials such as mackerel, sardines, or anchovies, which are rich in EPA and DHA, and are small cold water fish products at the bottom of the food chain, accumulating less heavy metals.


3. Look at the chemical form of fish oil

The common forms on the supplement market are natural triglyceride (TG) , re-esterified triglyceride (rTG) , and ethyl ester (EE) .

4. Certification information

You can check if the product has a reliable certification label, such as IFOS certification, TGA certification, USP certification .

  • IFOS certification: International Fish Oil Standards. A certification program specifically established for fish oil products. Certified fish oil is guaranteed in quality.

  • TGA certification: Therapeutic Goods Administration. It is the Australian government’s drug and medical device regulatory agency, supervising the quality, safety, and efficacy of products.

  • USP certification: United States Pharmacopeial Convention. It is an independent non-profit scientific institution. The USP mark indicates that the product has been laboratory verified and its component content is consistent with the label claim.


In summary, Omega-3 is beneficial to health, prioritize food supplementation, and eat all kinds of deep-sea fish! Secondly, it can be supplemented through fish oil, 1g per day for ordinary adults, safe and sufficient.


Of course, as with all nutritional supplements, there are risks if taken in excess, and there will be no problems as long as used according to the normal dosage.


If you want to use fish oil for treatment or targeted prevention of diseases, it is recommended to discuss with a doctor before using as required.


Peer review expert Guo Xiao

Distinct Clinic Internal Medicine Physician, Ph.D., Peking Union Medical College

References

1. Lembke, P. (2025). Omega-3 Fatty Acids: A Scientific Approach to Healthy Aging and Optimized Nutrition. Academic Press (Elsevier). ISBN: 978-0-443-29114-2.

2. Zanwar, A. A., Adekar, S. P., & Hegde, M. V. (Eds.). (2025). Omega-3 Fatty Acids: Keys to Nutritional Health and Disease (2nd ed.). Springer Nature Switzerland AG. ISBN: 978-3-031-84199-6.

3. Ahmad, M. F., Alsayegh, A. A., Khanam, A., et al. (2025). Efficacy of omega-3 fatty acids as a functional food: a multifaceted approach to health reinforcement. Journal of the Science of Food and Agriculture. DOI: 10.1002/jsfa.70346.

4. Calder, P. C., Cawood, A. L., James, C., et al. (2026). An overview of national and international long chain omega-3 polyunsaturated fatty acid intake recommendations for healthy populations. Nutrition Research Reviews, 39, e6, 1–12. DOI: 10.1017/S0954422425100279.

5. Chilton, F. H., Dutta, R., Reynolds, L. M., et al. (2017). Precision Nutrition and Omega-3 Polyunsaturated Fatty Acids: A Case for Personalized Supplementation Approaches for the Prevention and Management of Human Diseases. Nutrients, 9(11), 1165. DOI: 10.3390/nu9111165.

6. Weinberg, R. L., Brook, R. D., Rubenfire, M., & Eagle, K. A. (2021). Cardiovascular Impact of Nutritional Supplementation With Omega-3 Fatty Acids. Journal of the American College of Cardiology, 77(5), 593–608.


Disclaimer: The purpose of the article is to provide general health information, please consult a doctor for personal medical issues. For article reprint, please contact: medicine@distincthealth.com.

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