Recently, there has been a "fish oil trend" in the health care circle, and many friends around me are discussing whether to buy fish oil. A colleague swallows 2 pills of fish oil every day, saying that it can "lower blood lipids and prevent myocardial infarction"; a friend says that fish oil is an IQ tax, and eating it is useless! Is this fish oil a "health artifact" or an IQ tax? Is fish oil really worth buying? Today, let’s have a good chat about whether to buy fish oil or not.
What is fish oil?
Fish oil, as the name suggests, is an oil extracted from fish. It is popular mainly because it is rich in omega-3 fatty acids (also called n-3 fatty acids), the most famous of which are EPA and DHA.
· EPA (eicosapentaenoic acid): Often called "vascular scavenger", some studies believe that it can reduce the level of triglycerides in the body and has certain benefits in regulating blood lipids.
· DHA (docosahexaenoic acid): It is more famous and is called brain gold. To say it can make children smarter is actually a slight exaggeration. However, DHA is indeed an important component required for the growth of nervous system cells. It is contained in a large proportion in the cerebral cortex and retina, and plays an important role in the infant's intelligence and vision development.
Can heart disease be prevented?
There is currently not enough evidence to support this statement.
Fish oil is highly regarded, mainly because it prevents heart disease. The origin of this statement is that some scientists discovered that the Inuit people living in Greenland rarely suffer from heart disease, and their diet is mainly fish, seal and whale oil rich in omega-3 fatty acids, so it is said that fish oil can prevent heart disease.
Later, scientists conducted a large number of studies to verify it. However, some research has found thatThe low risk of heart disease among the Inuit is not only related to their lifestyle of playing with dogs, fishing, and eating seals, but more importantly, they have a special gene mutation involved in fat metabolism, allowing them to synthesize and utilize omega-3 fatty acids more efficiently.
Scientists have also done a lot of research on fish oil and omega-3 fatty acids on heart disease and cardiovascular health. However, the results were not optimistic. Some research results indicate that it is useful, while other research results indicate that it is useless. The results are very inconsistent, and there are even conflicting results (fish oil is considered harmful to heart health).
A 2012 report analyzed data from a large number of heart disease patients and found that the evidence that fish oil has a protective effect on future cardiovascular disease is insufficient [1].
A 2012 meta-analysis concluded that there is insufficient evidence to prove that fish oil and other omega-3 fatty acid supplements can reduce the risk of cardiovascular disease [2].
A 2018 study concluded that long-term use of fish oil (omega-3 fatty acids) does not reduce the risk of coronary heart disease or other cardiovascular diseases [3].
A 2018 study published in the New England Journal of Medicine found that supplementing with omega-3 fatty acids had no effect on reducing the odds of heart attack, stroke, or death from heart disease in middle-aged men and women with no known risk factors for heart disease [4].
A 2020 retrospective study of 86 studies involving 162,796 people found that increasing EPA and DHA intake slightly reduced the risk of coronary heart disease events and coronary heart disease death [5].
A 2024 study showed that eating fish oil in healthy people will increase the risk of heart disease [6].
In view of this, many authoritative international health organizations currently do not recommend "eating fish oil to prevent heart disease".
Chinese experts conducted a systematic analysis and found that although omega-3 fatty acids can effectively reduce triglyceride levels, clinical randomized controlled studies have shown mixed results in reducing the risk of atherosclerotic cardiovascular disease. At the same time, there is still confusion about its value in the prevention and treatment of cardiovascular diseases such as heart failure, arrhythmia, cardiomyopathy, hypertension, and sudden cardiac death.
Therefore, the current consensus among Chinese experts is that the current evidence only supports that high-purity and high-dose EPA treatment may bring cardiovascular benefits to patients with atherosclerotic cardiovascular disease (ASCVD), but the role of ω-3 fatty acids in the treatment of other cardiovascular diseases (such as arrhythmia, cardiomyopathy, hypertension, sudden cardiac death, etc.) requires further research [10].
Generally speaking, current research believes that eating foods rich in omega-3 fatty acids (such as fish) is good for health, but there is not enough evidence to show that eating fish oil can prevent heart disease. Those who tout fish oil as a "miracle drug that protects the heart and brain" are exaggerated.
What are the health benefits of fish oil?
So, is fish oil good for your health? What exactly does it do? In fact, from the current point of view, more evidence shows that fish oil has the following two health benefits:
First, fish oil can regulate triglyceride levels.
The American Heart Association (AHA) scientific recommendations on omega-3 fatty acid (fish oil) supplementation indicate that patients with coronary heart disease, heart failure, and hypertriglyceridemia may benefit from additional n-3 fatty acid supplementation.
The US FDA has approved Lovaza, a triglyceride-lowering drug, which contains at least 900 mg of omega-3 fatty acids per gram, including 465 mg of EPA and 375 mg of DHA [11]. If you have hypertriglyceridemia, you can take fish oil under the guidance of a doctor to regulate it.
Second, the DHA and EPA in fish oil are beneficial to the neurological development and vision development of infants and young children.
The latest version of my country's "Dietary Reference Intakes for Chinese Residents" (DRIs) believes that the appropriate daily intake of DHA+EPA during pregnancy is 250 mg, of which DHA is at least 200 mg; and for children of different ages, the appropriate daily intake of DHA is 100-250 mg [12].
As for other health effects, there is currently relatively little scientific evidence. Please do not regard it as a universal oil for preventing diseases.
Should I take fish oil?
Let me start with the conclusion: If you cannot guarantee to eat 300-500 grams of fish, shrimp and other aquatic products every week, you can choose to supplement with fish oil.
n-3 fatty acids such as DHA and EPA are indeed beneficial to health, and the evidence for the benefits of aquatic products (fish, shrimp and shellfish) is stronger than the evidence for ω-3 fatty acid supplements. Other nutrients in aquatic products besides ω-3 fatty acids may also exert their benefits. People who eat aquatic products usually lead a healthier lifestyle [13]. Therefore, the best way to obtain DHA and EPA is still through food.
DHA is the richest in aquatic products such as fish and shrimp, and can also provide high-quality protein, vitamin A, iron, zinc and other micronutrients. If conditions permit, it is of course best to eat some fish and shrimp every day.
my country’s dietary guidelines recommend [14] that the average daily intake of fish for adults is 120-200g, which is equivalent to eating fish twice a week or 300-500g. During pregnancy, you can increase your intake of fish to at least 2-3 times a week. In addition, the α-linolenic acid in perilla oil and flaxseed oil can also be converted into omega-3 fatty acids, and you can usually eat them instead.
However, many residents in our country still eat less aquatic products, and their intake of DHA and EPA is generally low.
For example, it may not be easy for people with severe morning sickness to eat fish and shrimp during pregnancy; cooking fish and shrimp for their children is time-consuming and involves worrying about fish bones; and some people may not like to eat fish. Therefore, if you really don’t eat enough fish and shrimp in your daily life, taking some fish oil is a simple and convenient way.
How to choose fish oil?
There are many types of fish oil products on the market, how do you choose? It is recommended that you pay attention to a few points when choosing:
1. Choose formal channels and brand products
Try to choose products from big brands in regular supermarkets and e-commerce platforms, which are generally more reliable.
2. Pay attention to distinguish between fish oil and cod liver oil
"Fish oil" is different from cod liver oil. The main components of cod liver oil are vitamin A and vitamin D. Many parents want to supplement their children with vitamin A and vitamin D to prevent rickets, so they should choose cod liver oil; and if they want to supplement DHA, they should choose fish oil.
3. Check the product concentration
The most important indicators in fish oil are EPA and DHA. Many people only look at the content of EPA and DHA when making a choice. They also look at the concentration, i.e. the content of EPA+DHA in a pill of fish oil.
Generally speaking, the higher the concentration, the better the product quality. For example, a pill of fish oil is 1000mg, which contains 600mg of omega-3 fatty acids (DHA500mg, EPA 100mg). Although some fish oils appear to be larger in size, the omega-3 fatty acid content may be less. Everyone needs to compare carefully.
4. Check the dosage and eat in moderation.
It is generally believed that the average adult only needs 200 mg of DHA per day, and the daily intake of DHA+EPA during pregnancy is 250 mg, of which DHA must be at least 200 mg.
Everyone should consume it in moderation according to the product concentration and dosage. Although the safety range of DHA+EPA is very wide, and it is safe to consume 2 grams per day, so there is no need to worry too much about safety issues, but fish oil is also fat after all.
How many grams of fish oil should you eat and how much fat should you lose from your diet to ensure a balanced diet. Moreover, once you open the package of the fish oil you buy at home, you should eat it as soon as possible. If you can’t finish it, store it in a cool and dark place to prevent the oxidative rancidity of fatty acids caused by light, high temperature, etc.
Generally speaking, fish oil cannot be mythed, nor can it be completely denied.
But for most people, it is best if they can ensure their nutritional intake through a balanced diet and eat more fish and aquatic products rich in omega-3 fatty acids. If you cannot eat enough fish and aquatic products for various reasons, you can also take some fish oil appropriately.
Be cautious when purchasing, and do not blindly follow the trend and buy products with exaggerated publicity. It is best to proceed under the guidance of a doctor or professional nutritionist.
References
[1] Kwak SM, Myung SK, Lee YJ, Seo HG; Korean Meta-analysis Study Group. Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: a meta-analysis of randomized, double-blind, placebo-controlled trials. Arch Intern Med. 2012 May 14;172(9):686-94. doi: 10.1001/archinternmed.2012.262. PMID: 22493407.
[2] Evangelos C. Rizos, et al .Association Between Omega-3 Fatty Acid Supplementation and Risk of Major Cardiovascular Disease Events A Systematic Review and Meta-analysis. JAMA. 2012;308(10):1024-1033. doi:10.1001/2012.jama.11374
[3] Aung T, et al. Associations of Omega-3 Fatty Acid Supplement Use With Cardiovascular Disease Risks: Meta-analysis of 10 Trials Involving 77?917 Individuals. JAMA Cardiol. 2018 Mar 1;3(3):225-234.
[4] Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, Gibson H, Albert CM, Gordon D, Copeland T, D'Agostino D, Friedenberg G, Ridge C, Bubes V, Giovannucci EL, Willett WC, Buring JE; VITAL Research Group. Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. N Engl J Med. 2019 Jan 3;380(1):23-32. doi: 10.1056/NEJMoa1811403. Epub 2018 Nov 10. PMID: 30415637; PMCID: PMC6392053.
[5] Abdelhamid AS, Brown TJ, Brainard JS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews. 2020;(3):CD003177. Accessed at cochranelibrary.comLink to External Link Policy on November 11, 2023.
[6] Harris E. Fish Oil Pills Associated With Increased Risk of Heart Problems in Healthy People. JAMA. 2024;332(2):97. doi:10.1001/jama.2024.10340
[7] Omega-3 acid ethyl esters - containing medicinal products for oral in use in secondary prevention after myocardial infarction[EB/OL]. (2019-02-01) [2022-06-01].
https://www. ema. europa. eu/en/medicines/human/referrals/omega-3-acid-ethyl-esters-containingmedicinal-products-oral-use-secondary-prevention-after.
[8] Omega-3 Fatty Acids. Fact Sheet for Consumers https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/
[9] Eric B. Rimm, et al. Seafood Long-Chain n-3 Polyunsaturated Fatty Acids and Cardiovascular Disease: A Science Advisory From the American Heart Association. Circulation. 2018;May 17.
[10] Chinese expert consensus on the role of Omega-3 fatty acids in the prevention and treatment of cardiovascular diseases [J]. Chinese Journal of Circulation, 2023, 38(02): 116-130.
[]https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/021654s023lbl.pdf
[11] Dietary Reference Intakes (DRIs) of Chinese Residents 2023.
[12] https://www.nccih.nih.gov/health/omega3-supplements-what-you-need-to-know
[13] Dietary Guidelines for Chinese Residents 2022.
Planning and production
Author | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center, Member of the Health Communication Branch of the Chinese Association of Preventive Medicine
Review丨Zhang Yu Chinese Center for Disease Control and Prevention Researcher/Ph.D. National Health Science Popularization Expert Member of the Health Communication Working Committee of the Chinese Medical Doctor Association
Planning丨Zhen Xi
Editor丨Zhen Xi
Reviewer丨Xu Lai, Lin Lin