Peanut oil, olive oil, sunflower oil... Which oil should I buy? This article explains it all!

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1. Polyunsaturated fatty acids are better than monounsaturated fatty acids and better than saturated fatty acids.

2. Among polyunsaturated fatty acids, n-3 polyunsaturated fatty acids are superior to n-6 polyunsaturated fatty acids.

3. Compared with animal edible oils (such as lard), vegetable edible oils are healthier. Pay attention to controlling the intake of animal and vegetable oils. The nutritional components of blended oils are more reasonably distributed.

4. When purchasing edible oil, as long as it meets the national standards, it can be eaten. Be careful not to buy oil squeezed by small workshops. When purchasing, try to buy small packages and use them up within 3 months.

5. When cooking, pay attention to the total daily intake between 25 and 30 grams, control the oil temperature not to overheat, and use less cooking methods such as frying. Do not reuse used oil.

Characteristics of different types of edible oil

Cooking oil has always been a favorite and cautious choice for food lovers. Deep-fried and pan-fried foods are crispy and delicious, easily conquering people's senses and taste buds. However, eating too much of these foods is obviously harmful to health, and can increase the risk of obesity, cardiovascular and cerebrovascular diseases, cancer and other diseases.

According to the "Dietary Guidelines for Chinese Residents (2022 Edition)", residents' daily intake of edible oil should be controlled at 25-30 grams. [1] However, this is not enough. 25-30 grams of edible oil does not mean just any kind of oil will do. A healthy diet also has clear requirements for the composition of edible oil.

How should we choose and consume cooking oil? What are the differences between different types of cooking oil? Which type of oil is better? Is it okay to only consume one type of oil for a long time? We will answer these questions one by one today.

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The human body has different requirements for the three fatty acids in oils

Oil is an essential nutrient for the human body. More than 99% of cooking oil is fat, and the difference in fat is mainly reflected in the fatty acids. The fatty acids in oil can be divided into three categories: saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids. The human body needs all three types of fatty acids, but the required amounts are not the same.

The Dietary Reference Intake of Nutrients for Chinese Residents recommends that the ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in the fats and oils we consume should be less than 1:1:1 (specifically, monounsaturated fatty acids: polyunsaturated fatty acids = 1:1, and the ratio of saturated fatty acids to monounsaturated fatty acids is less than 1). [2] So what effects do different fatty acids have on the human body?

1. Saturated fatty acids

Saturated fatty acids can be synthesized by the human body, but if they are taken in excessive amounts from the outside, obesity is likely to occur. Excessive intake of saturated fatty acids will increase blood cholesterol, triglycerides, and low-density lipoprotein cholesterol, making the blood viscous, which in turn causes atherosclerosis and affects the health of the cardiovascular system.

In the modern diet, we are very likely to consume too much saturated fatty acids, so we must strictly control the intake of saturated fatty acids. The World Health Organization recommends that saturated fatty acids should not account for more than 10% of the daily calorie intake of adults and children.

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2. Unsaturated fatty acids

Unsaturated fatty acids are healthier fatty acids that help lower the body's bad cholesterol (low-density lipoprotein) levels and increase good cholesterol (high-density lipoprotein) levels, lower blood lipids, and reduce the risk of cardiovascular disease.

Unsaturated fatty acids are divided into monounsaturated fatty acids and polyunsaturated fatty acids. Monounsaturated fatty acids mainly refer to n-9 series fatty acids, which can be synthesized by the human body itself, and it is the most abundant fatty acid in human cells, so it does not need to be specifically ingested through food and is not an essential fatty acid for the human body.

3. Polyunsaturated fatty acids

Polyunsaturated fatty acids contain two types of fatty acids that the human body cannot synthesize on its own and must be obtained from food - linoleic acid (n-6 polyunsaturated fatty acids) and α-linolenic acid (n-3 polyunsaturated fatty acids).

Among them, the sources of n-3 polyunsaturated fatty acids are limited. They are only found in relatively rich amounts in seafood, nuts and certain varieties of vegetable oils (such as flaxseed oil and sesame oil). Pay attention to additional supplementation.

n-6 polyunsaturated fatty acids are widely present in food and have many sources. Although the human body needs them, in fact, the intake of n-6 polyunsaturated fatty acids in our daily diet is often too high. On the contrary, consuming a large amount of n-6 polyunsaturated fatty acids is unhealthy for the body .

Only when the intake of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids is balanced, it is most beneficial to health . Studies have shown that the best ratio of n-6 and n-3 polyunsaturated fatty acids is between 1:1 and 4:1.

In summary, among the three fatty acids in oils:

1. Polyunsaturated fatty acids are better than monounsaturated fatty acids and better than saturated fatty acids.

2. Among polyunsaturated fatty acids, n-3 polyunsaturated fatty acids are superior to n-6 polyunsaturated fatty acids.

Therefore, when choosing edible oil, we should pay attention to the priority levels of these fatty acids.

The difference between various edible oils is mainly due to the different fatty acid compositions.

Common edible oils on the market can be divided into two categories: animal edible oils and vegetable edible oils. Animal edible oils come from natural animal fats and oils, and common ones include lard, tallow, butter, etc., which are generally solid at room temperature .

Vegetable edible oils are derived from the fruits, seeds, and germs of natural plants. Common ones include soybean oil, peanut oil, rapeseed oil, sunflower oil, corn oil, olive oil, and sesame oil .

Nutritional classification of common edible oils: Data from the Dietary Guidelines for Chinese Residents (2022)

As can be seen from the above figure, animal edible oils are high in saturated fatty acids and cholesterol, so excessive consumption is not recommended. However, animal edible oils are not without merit. They also contain other nutrients that are beneficial to human health. For example, cream and butter are very rich in vitamin A; lard contains more vitamins A, D, K, B6, and B12; lard can also help clear the intestines, and can relieve constipation for people with constipation .

Foreign nutritionists have also found that animal edible oils contain lipoproteins, which have the effect of prolonging life. Therefore, animal edible oils are not completely forbidden to be eaten, but the intake should be controlled, and the calories consumed should not exceed 10% of the total daily calorie intake .

Vegetable cooking oil is rich in unsaturated fatty acids. Therefore, it is indeed a better choice to give priority to vegetable cooking oil as daily cooking oil .

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We have also summarized the other nutritional components, advantages and disadvantages of several common vegetable cooking oils and the cooking methods they are suitable for:

Eat different cooking oils, don't eat the same one for a long time.

Taking all factors into consideration, each type of vegetable cooking oil has its own unique nutritional value, so you should change the cooking oil you eat and don't eat the same one for a long time .

But for many families, they buy a large barrel of oil and use it for several months. During these months, the intake ratio of the three fatty acids is also unbalanced. When changing the oil, they also have to consider what oil to buy next time, which is also troublesome. In this case, blended oil is a better choice .

Blended oil is edible oil made by mixing these different vegetable oils together according to needs . The ideal blended oil makes the ratio of the three fatty acids healthier and more balanced through the ratio of different vegetable oils. Its overall nutritional value will be higher than that of a single variety of vegetable oil .

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Although blended oil is a better choice, it should be noted that the same blended oil only contains a few specific types of vegetable oils. If you eat it frequently, the diversification effect will not be particularly ideal. Therefore , even if you eat blended oil, it is recommended to change the variety and mix different varieties of blended oil together .

Moreover, the blended oil also depends on which oils are blended together. If the proportion of the three fatty acids is out of balance , for example, the blended oils are all rich in monounsaturated fatty acids and n-6, but lack varieties rich in n-3 polyunsaturated fatty acids. Or one of the varieties used in the blend accounts for the vast majority, while the other varieties only account for a small amount.

Therefore, long-term consumption of these blended oils will not actually achieve the effect of balanced intake of fatty acids .

The new national standard "National Food Safety Standard Vegetable Oil (GB2716-2018)" requires that "the label of edible vegetable blended oil should indicate the proportion of various edible vegetable oils" [4]. We should pay attention to the proportion of each single variety of vegetable oil on the label. If the proportion of various fatty acids is also marked, we can see whether its ratio is scientific.

The Chinese Dietary Reference Intake of Nutrients recommends that the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids in the fats and oils we consume should be less than 1:1:1. [2] This is undoubtedly the most scientific principle for using oils, and everyone must pay attention to it.

Here I would like to remind everyone that the fatty acid ratio of some commercially available blended oils is not 1:1:1. Please pay attention to the ratio when purchasing .

No cooking oil is perfect . When buying cooking oil, we recommend that you not only switch between single types of cooking oil, but also try to switch between blended oils. Only by mixing and matching oils can you eat nutritiously and healthily.

Pay attention to these when purchasing cooking oil and cooking

1. When buying cooking oil

1.1 Look at the quality level

Edible oil is divided into four grades: primary, secondary, tertiary, and quaternary (olive oil is a special case, which is divided into virgin olive oil: extra virgin, medium, refined, and blended). So does the higher the grade, the higher the quality of the oil? Actually, not always.

Grade 1 and 2 cooking oils are of high purity, less impurities, clear color, lighter aroma and taste, less smoke during cooking, and suitable for high-temperature stir-frying and frying. However, the disadvantage is that the degree of refining is too high, resulting in the loss of nutrients in the oil.

The third and fourth grade cooking oils are just the opposite. They have low purity, many impurities, darker color or moderate turbidity, stronger aroma and taste, more smoke when cooking, and are more suitable for low-temperature cooking. But their advantage is that they retain the nutrients in the oil to the greatest extent.

No matter which grade of oil, as long as it meets the national standards, it can be eaten normally. We can choose according to the demand for nutrients, the need for flavor and different cooking methods .

1.2 Look at the processing technology

Pressed oil uses physical methods to separate oil from raw materials, retaining more nutrients. The cost of the pressing process is higher and the price is more expensive . Extracted oil is purified through a series of chemical processes. It has a high oil yield, low production cost and is relatively cheap.

Many people like to squeeze oil, thinking it is healthier; they don't like leached oil, thinking it will leave chemical residues. In fact, there is no need to worry too much. As long as the edible oil meets the national standards and is purchased from a big brand in a regular supermarket, it is safe and can be eaten with confidence .

But be careful not to buy bulk oil of unknown origin, and don't choose oil squeezed by primitive methods in small workshops.

1.3 Check the production date and shelf life

The closer the production date, the better, and the farther the expiration date, the better. Generally, the shelf life of edible oil is 18 to 24 months. It should be stored in a cool, dry, dark and sealed place .

1.4 Try to buy small packages

Once the edible oil is opened, it will react with the air to oxidize, accelerating the deterioration of the oil. So try to buy edible oil in small bottles, cover the bottle tightly after each use, and use it up within 3 months after opening .

2. When cooking with cooking oil

2.1 Control total intake

The "Dietary Guidelines for Chinese Residents (2022 Edition)" recommends that residents' daily intake of edible oil should be controlled between 25 and 30 grams. For health reasons, this recommended value is recommended to be strictly followed .

2.2 Control cooking oil temperature

Don't wait until the oil smokes before putting the ingredients in to cook , because some cooking oils, such as soybean oil, corn oil, rapeseed oil, sunflower oil, extra virgin olive oil, walnut oil, sesame oil, flaxseed oil, perilla oil, grapeseed oil, etc., are not suitable for high-temperature cooking.

2.3 Control cooking methods

Avoid cooking methods such as frying and deep-frying . Frying and deep-frying not only produce harmful substances including trans fatty acids, but also increase the intake of fats. Their aroma and taste also make us prone to overeating, further causing metabolic diseases.

In fact, delicious dishes can be cooked with less oil. The cooking methods should be mainly steaming, boiling, braising, stewing and stir-frying, with less oil for frying and deep-frying. An air fryer can be used instead of frying.

2.4 Use new oil every time

Many families will save the oil after frying food and continue to fry other foods or use it for cooking. However, oil that is repeatedly fried can easily produce carcinogens , such as trans fatty acids, benzopyrene, acrylamide, heterocyclic amines, etc. Long-term consumption will bring health risks. Experts recommend that no matter what cooking method is used, the oil should only be used once, and new oil should be used every time .

Finally, I hope that after reading this article, everyone will have a clearer understanding of the selection and use of cooking oil, and use and eat oil in a healthy way!

References

[1] Dietary Guidelines for Chinese Residents (2022 Edition)
[2] Dietary Reference Intakes of Nutrients for Chinese Residents (2017 Edition) [3] Yang Yuexin, ed. Standard Edition of Food Composition Tables for China. 6th Edition. Volume 1, Volume 2. Peking University Medical Press. [4] National Food Safety Standard. Vegetable Oil. GB 2716-2018.

Author: Zeng Xinyue, popular science creator

Review | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center