Is it true that fish oil can prevent cardiovascular disease?

Many people may have heard that "taking fish oil can lower blood lipids and prevent cardiovascular disease". Previous studies have found that Eskimos who often consume fish and marine fish oil have a low incidence of cardiovascular disease despite a high-calorie, high-fat, and high-cholesterol diet. Their incidence and mortality rates of coronary heart disease and diabetes are only 10% of those of Danes of the same age, suggesting that fish oil has a certain effect in lowering blood lipids and the risk of cardiovascular disease.

Is fish oil really so miraculous as a nutritional supplement? Combining the latest medical evidence and clinical experience, today we will analyze the efficacy of fish oil and related misunderstandings for you.

What is fish oil?

Fish oil refers to the general term for all oily substances in fish, including body oil, liver oil and brain oil. Its main active ingredients are ω-3 polyunsaturated fatty acids, the most important of which are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid).

Studies have shown that DHA and EPA can lower blood pressure, lower bad cholesterol (very low density and low density lipoprotein cholesterol), and raise good cholesterol (high density lipoprotein cholesterol). Eating more fish oil or fish with high DHA and EPA content can indeed lower blood lipids.

International clinical studies have shown that for patients with hypertriglyceridemia who are still poorly controlled after taking statins, it is recommended to add fish oil to further strengthen lipid-lowering treatment. Daily intake of ω-3 polyunsaturated fatty acids can reduce triglycerides by 20% to 30%.

Here, everyone needs to understand a misunderstanding, that is, "fish oil ≠ cod liver oil". Although fish oil and cod liver oil are both extracted from fish and their names are only one letter different, they are two completely different nutritional supplements. Cod liver oil is extracted from the livers of non-toxic marine fish such as sharks and cod. It mainly contains vitamin A and vitamin D and is often used to prevent and treat night blindness and rickets.

Can fish oil really prevent cardiovascular disease?

Randomized controlled clinical trials (RCTs) before 2010 found that fish oil is beneficial to cardiovascular health. However, after 2010, the results of several strictly controlled randomized controlled clinical trials failed to confirm its cardiovascular protective effect. Therefore, there is still no consensus internationally on whether ω-3 polyunsaturated fatty acids can prevent cardiovascular disease.

Some research evidence suggests that the cardiovascular benefits of fish oil may not be achieved by lowering triglyceride levels, but rather because patients taking fish oil pay more attention to their own health and reduce the risk of subsequent cardiovascular disease by quitting smoking, drinking, and better controlling other risk factors such as blood pressure and blood sugar.

How to use fish oil specifically?

Although fish oil has a certain lipid-lowering effect, it is pseudoscience to talk about the efficacy without considering the dosage. The more fish oil you eat, the better. It is especially important to note that the fish oil health products currently sold on the market are not drugs. Their ω-3 polyunsaturated fatty acid content and purity are low, their stability is poor, and they lack strict regulatory standards and medical evidence. Therefore, the clinical research conclusions and guidelines recommended at home and abroad are not applicable to fish oil health products.

The 2020 "Guidelines for Healthy Lifestyles in China to Prevent Cardiovascular and Metabolic Diseases" recommends that Chinese residents should appropriately increase the intake of foods rich in ω-3 polyunsaturated fatty acids in their diets. The U.S. Food and Drug Administration (FDA) recommends that the average intake of prescription fish oil preparations be around 1.6 g/day.

Warm reminder: There is evidence that fish oil can reduce triglycerides, but it is still unclear whether it can reduce the risk of cardiovascular disease. If you want to prevent cardiovascular disease from the aspects of diet and lifestyle, you should still follow the following tips: "Eat more fish, eat less meat, move your legs, exercise more, quit smoking and drinking", hoping to help everyone establish the concept of scientific prevention of cardiovascular disease.