Eat a little of it every day to nourish your brain, protect your eyes and skin! You can do it in just 2 steps!

As early as the 1940s, people found that the Eskimos in Greenland lacked fruits and vegetables in their diet, but their blood lipid levels were lower than those of Danish residents of the same age, and their risk of myocardial infarction was also lower. This aroused people's curiosity, and it was speculated that this might be due to the fact that some ingredients in the marine fish they consumed in large quantities were beneficial to health.

To verify this conjecture, more and more studies have begun to focus on Omega-3 fatty acids in marine fish and have discovered many health benefits.

What are Omega-3 fatty acids?

Omega-3 fatty acids, also known as n-3 fatty acids or ω−3 fatty acids, are essential fatty acids that cannot be synthesized by the human body and must be supplemented through food. There are many types of omega-3 fatty acids, the most common and beneficial to health in human food are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), as well as alpha-linolenic acid (ALA), which can be converted into these two fatty acids.

So what benefits do Omega-3 fatty acids have for the human body? And how can we supplement them? Let’s talk about it in detail today.

01

Lowering blood lipids

There have been many studies on the effect of Omega-3 fatty acids in lowering blood lipids, and the evidence is very sufficient.

A meta-analysis of 86 clinical trials published as of February 2019 involving 162,796 participants showed that additional supplementation with EPA and DHA in oil or capsule form (including concentrated fish oil and algae oil) could reduce serum triglycerides by approximately 15%.

It is important to note that this effect only lowers triglycerides, not LDL cholesterol.

02

Reduce cardiovascular disease risk

Several studies have shown that the intake of omega-3 fatty acids can reduce the risk of sudden heart attack, cardiac death after acute myocardial infarction, heart failure and stroke. However, whether omega-3 fatty acid supplementation in capsule form can really prevent cardiovascular disease is still controversial.

Some scholars believe that the original level of omega-3 fatty acids in the subjects should be considered. For people with particularly low intake levels, high-dose supplementation can achieve the desired effect. For patients with sufficient intake, the benefits of supplementation are not significant. This can explain the differences in some research conclusions.

03

Protect cognitive function

Multiple studies have shown that insufficient intake of omega-3 fatty acids is associated with cognitive decline and an increased risk of developing Alzheimer's disease.

Supplementation with omega-3 fatty acids can improve cognitive status, maintain normal cognitive function, and prevent age-related cognitive deficits in young and middle-aged adults.

Improvements were also observed in people who already had mild cognitive impairment, but there may not be such an effect for the elderly and those who already had Alzheimer's disease. Therefore, it is important to develop the habit of consuming enough omega-3 fatty acids when you are young.

04

Protect your eyes

Omega-3 fatty acids such as DHA are involved in maintaining the normal function of the eye's photoreceptors and visual cortex, etc. A lack of omega-3 fatty acids may lead to vision problems.

Although there is still controversy about the effectiveness of omega-3 fatty acids as a dietary supplement in treating dry eyes, eating more foods rich in omega-3 fatty acids in your daily diet is still beneficial for preventing dry eyes.

Because some studies have shown that Omega-3 fatty acids help relieve inflammation on the surface of the eye, and can also help the meibomian glands of the eyes secrete the lipid layer of the tear film and increase the stability of the tear film.

05

Promotes Skin Health

Several studies have shown that consuming EPA and DHA can reduce the extent of skin damage caused by UV rays, thereby delaying skin aging and protecting skin health.

06

Improve sleep quality

Observational studies have shown that people who consume enough omega-3 fatty acids have good sleep quality. Intervention studies have also confirmed this. A 26-week trial found that healthy young and middle-aged people who took DHA and EPA not only fell asleep more easily, but also had a longer total sleep time.

07

Promote fat loss

Omega-3 fatty acids can help reduce body fat and fight obesity by affecting the deposition and consumption of fat. Clinical studies have found that even when energy levels remain unchanged, additional supplementation with Omega-3 fatty acids can reduce body fat. Studies have also shown that restricting energy while supplementing with Omega-3 fatty acids can reduce weight more effectively than simply restricting energy. In addition, Omega-3 fatty acids from a variety of sources and types have this effect. Some studies have also found that supplementing with Omega-3 fatty acids combined with aerobic training can more effectively reduce body fat.

08

Imbalance

Despite their many health benefits, omega-3 fatty acids are on the decline in the modern diet.

In addition to the Omega-3 series, food also contains an Omega-6 series. Both are essential fatty acids, but they are only beneficial in the right ratio. In the hunting-gathering era and the agricultural era, the ratio of Omega-3/Omega-6 in the human diet was about 1:1, which is also considered to be a relatively suitable ratio by current research . However, since the industrialization era, especially in the Western diet pattern, Omega-6 has increased sharply, while Omega-3 has decreased sharply, causing this ratio to drop to 1:15 or even 1:20.

This unbalanced ratio is not good for our health and is even considered a factor that leads to chronic inflammation and increased risk of multiple chronic diseases. The Omega-6 series and the Omega-3 series need to compete for the same metabolic enzymes, and too much Omega-6 means that Omega-3 cannot be metabolized smoothly. Although the Omega-6 series is widely distributed in food and most people are not deficient, the Omega-3 series is relatively scarce, and the transition from wild to farmed and cultivated has also reduced the ratio of Omega-3:Omega-6 in food. Therefore, in order to restore the unbalanced ratio, we need to consume more foods rich in the Omega-3 series in our daily diet.

09

Appropriate intake

Most authoritative organizations believe that it is difficult to give a specific recommended amount, but based on the conclusions of experts from FAO, WHO, European Food Administration and other organizations, the total daily intake needs to reach the following amount to meet demand.

1. Adult men and non-pregnant/lactating women: 250 mg EPA+DHA per day.

2. Pregnant and lactating women: Since docosahexaenoic acid (DHA) is beneficial to the development of fetal brain and retinal function, the demand is higher. It is recommended to consume 300 mg of EPA+DHA per day, of which at least 200 mg is DHA.

10

How to get enough

Omega-3 fatty acids

To increase your dietary intake of omega-3 fatty acids, two measures are recommended:

1. Replace other meat with fish 2-3 times a week.

Fish is the best food source for EPA and DHA, and marine fish contains more Omega-3 fatty acids than freshwater fish. Therefore, it is recommended to eat fish 2-3 times a week and appropriately reduce the intake of other meats.

2. Change the type of cooking oil.

The edible oils rich in Omega-6 fatty acids include corn oil, sunflower oil, safflower oil, cottonseed oil and soybean oil. Therefore, it is not advisable to consume too much of these oils. It is recommended to use oils rich in Omega-3 fatty acids, such as flaxseed oil, perilla oil, walnut oil, etc. These oils are rich in α-linolenic acid, which can be converted into EPA and DHA. Although the conversion efficiency is low, it is still beneficial to increase the total amount of these oils.

It should be noted that flaxseed oil, perilla oil and walnut oil are not resistant to high temperatures and cannot be used for cooking. They are recommended for use in cold dishes.

In addition, the intake of trans fatty acids should be minimized because trans fatty acids affect the efficiency of the conversion of α-linolenic acid into EPA and DHA.

Author: Gu Zhongyi

Review | Zhang Jiguo, Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention