How to choose from a wide variety of fish oil products

Author: Cui Yihui, registered dietitian, master of medicine

Reviewer: Wang Junbo, Associate Professor and Doctoral Supervisor, Peking University Health Science Center

Looking at the "fat family", the members are not identical "twins", and their "appearances" vary greatly. For example, lard and peanut oil are different because their basic structural units - fatty acids are different. Therefore, the key to distinguishing good and bad fats in food is to distinguish good and bad fatty acids.

●Classification of fatty acids

There are many ways to classify fatty acids. The most commonly used method is to divide fatty acids into two categories: saturated fatty acids and unsaturated fatty acids according to the degree of saturation of fatty acids.

➣Saturated fatty acids

As the name implies, substances with saturated structures are stable, inactive, "obedient" and "not a big worry". Saturated fatty acids have the function of storing and supplying energy, but eating too much can cause elevated blood lipids and lead to cardiovascular and cerebrovascular diseases such as atherosclerosis. Therefore, although it is impossible to completely limit the intake of foods containing a large amount of saturated fatty acids (animal oils such as fat meat, lard, and butter; vegetable oils such as palm oil and cocoa butter), you should try to eat as little as possible.

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➣Unsaturated fatty acids

Substances with "unsaturated" structures are the opposite of "saturated" substances. They are unstable, active, "dishonest", and easy to make people "worry" (worry about them being oxidized). Therefore, they have many special physiological activities. Unsaturated fatty acids are mainly found in vegetable oils such as olive oil, peanut oil, and rapeseed oil, as well as marine animals such as deep-sea fish and shellfish. Unsaturated fatty acids are very important to the human body, and how to ingest unsaturated fatty acids is also very important.

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●It is best to eat with cooking oil

Unsaturated fatty acids are mainly divided into three categories, namely n-3, n-6 and n-9. n-9 is a monounsaturated fatty acid. The higher the proportion of n-9 in edible oil, the better. For example, olive oil is rich in n-9 fatty acids. n-3 fatty acids (α-linolenic acid, EPA, DHA, etc.) and n-6 ​​fatty acids (including linoleic acid, arachidonic acid, etc.) are polyunsaturated fatty acids. The intake ratio is generally 1: (4.5-5), which is more suitable.

Common cooking oils on the market, such as peanut oil, soybean oil, corn oil, sunflower oil, etc., often contain excess n-6 and insufficient n-3. Excess n-6 will reduce the absorption and utilization of n-3, thereby affecting fat metabolism, and further leading to an increased risk of chronic diseases such as heart disease, diabetes, and arthritis.

Try not to eat only one type of cooking oil, but eat them in combination (for example, mix 1 part flaxseed oil with 2 parts soybean oil or 2 parts peanut oil) to ensure a balanced intake of dietary fatty acids.

Of course, no matter what kind of oil you use, you should not eat it without moderation. The total intake of edible oil is also very important to your health. It is best to control the daily intake of edible oil to 25-30 g.

●Nutritional effects of deep-sea fish oil

The main components of deep-sea fish oil are two n-3 polyunsaturated fatty acids, EPA and DHA. Land plants contain almost no EPA and DHA. Among aquatic products, deep-sea animals, especially deep-sea fish, have higher levels of EPA and DHA.

➣Lower blood lipids and maintain cardiovascular health: n-3 polyunsaturated fatty acids can reduce the levels of low-density lipoprotein cholesterol and triglycerides in the blood, thereby reducing blood viscosity and preventing thrombosis. They can also protect the elasticity of blood vessel walls, allowing blood to flow smoothly, preventing atherosclerosis, and helping to protect against cardiovascular diseases.

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➣Fight inflammation and relieve joint pain and discomfort, prevent rheumatoid arthritis: n-3 polyunsaturated fatty acids have anti-inflammatory effects, can reduce swelling and pain, and relieve the discomfort of arthritis.

➣Eliminate migraines: n-3 polyunsaturated fatty acids can promote blood circulation in the brain by reducing blood viscosity, and can also inhibit the secretion of prostaglandins that cause pain and inflammation.

➣Nourish brain cells, improve memory, and prevent Alzheimer's disease: DHA, known as "brain gold", can promote and coordinate the conduction of neural circuits, maintain the normal functioning of brain cells, and thus enhance concentration, memory, and attention.

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➣Protect eyesight, prevent vision deterioration, and prevent presbyopia.

➣ Improve the body's immune regulation ability.

●How to choose fish oil products

➣ Look at the packaging: EPA and DHA are easily oxidized, so they need to be stored away from light. If the fish oil is packaged in transparent packaging, its protection of the active ingredients is definitely not as good as that of dark or brown packaging that can avoid light.

➣ Look at the color: high-quality fish oil is generally light yellow and crystal clear. The lower the quality, the yellower the color of the fish oil, similar to orange.

➣ Look at the source: Fish oil products that come from fish fat in unpolluted deep sea areas are "superior" in quality.

➣ Look at the ingredients: The reasonable ratio of EPA and DHA is one of the key factors in choosing fish oil. The currently recognized "golden ratio" is 3:2. This ratio allows the human body to absorb more fully and can better play the role of lowering blood lipids. In addition, fish oil with added vitamin E can effectively protect the activity of EPA and DHA, which is also a key factor in our selection of fish oil.

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➣ Look at the price: If you think about it carefully, you will understand that how can a bottle of fish oil products with high purity, which comes from the fat of fish in pollution-free deep-sea cold waters, be bought for only thirty or fifty yuan?

Finally, although deep-sea fish oil is good, it is not suitable for everyone. When taking fish oil products that meet the standards, there are three things to note.

❖This product cannot replace medicine.

❖Use with caution in children, pregnant women and lactating women.

❖Contraindicated in patients with bleeding disorders and bleeding tendency.