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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 better than N-6 polyunsaturated fatty acids.
3. Compared to animal cooking oils (such as lard), vegetable cooking oils are healthier. Animal vegetable oil intake should pay attention to the control amount. The distribution of nutrients in the blended oil is more reasonable.
4. When purchasing edible oil, as long as it meets the national standard, you can eat it, and be careful not to buy oil pressed by the soil method of small workshops. Try to buy small packages when purchasing, and use them within 3 months.
5. When cooking, pay attention to the total daily intake between 25~30 grams, control the oil temperature not to overheat, and use less cooking methods such as frying. Do not reuse used oil that has already been used.
Characteristics of different varieties of edible oil
Cooking oil has long made food lovers love and be cautious. Fried, fried and other high-oil foods are crispy and delicious, which is easy to conquer people's senses and taste buds. However, eating too much of these foods is obviously detrimental to health, which will sharply 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 edible oil intake needs to be controlled at 25~30 grams. [1] However, it is not enough to do this, 25~30 grams of edible oil is not just any kind of oil to eat, healthy diet also puts forward clear requirements for the composition of edible oil.
**How should edible oil be selected and eaten? What is the difference between the various varieties of cooking oil? Which oil is better? Is it okay to eat only one type of oil for a long time? ** We will answer all these questions today.
The three fatty acids in oils and fats differ in the amount required by the human body
Oils and fats are essential nutrients for the human body. More than 99% of the ingredients in cooking oil are fat, and the difference in fat is mainly reflected in fatty acids. The fatty acids of oil can be divided into three categories: saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. These three fatty acids are needed by the human body, but the demand is not the same.
The "Dietary Nutrient Reference Intakes for Chinese Residents" recommends that the ratio of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids in the oils and fats we consume is about 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 are the effects of different fatty acids on the human body?
1. Saturated fatty acids
Saturated fatty acids can also be synthesized by the human body itself, and if they are taken in excess from the outside world, it is easy to produce obesity. Excessive intake of saturated fatty acids will lead to increased blood cholesterol, triglycerides, and LDL cholesterol, making the blood viscous, and then causing atherosclerosis, which will affect the health of cardiovascular and cerebrovascular diseases.
In the modern diet, we have a great probability of excessive intake of saturated fatty acids, so we must strictly control the intake of saturated fatty acids. The World Health Organization recommends that adults and children should not exceed 10% of the daily calorie intake of saturated fatty acids.
2. Unsaturated fatty acids
Unsaturated fatty acids are healthier fatty acids that help lower the body's bad cholesterol (LDL) levels and increase good cholesterol (HDL) levels, lower blood lipids, and reduce the risk of cardiovascular disease.
Unsaturated fatty acids are divided into monounsaturated fatty acids and polyunsaturated fatty acids. Among them, 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 specially ingested through food, not essential fatty acids.
3. Polyunsaturated fatty acids
Polyunsaturated fatty acids contain two fatty acids that the body cannot synthesize on its own and must be ingested from food - linoleic acid (belonging to n-6 polyunsaturated fatty acids) and α-linolenic acid (belonging to n-3 polyunsaturated fatty acids).
Among them, the source of n-3 polyunsaturated fatty acids is limited, and it is only abundant in seafood, nuts and individual varieties of vegetable oils (such as flaxseed oil and flax oil), so pay attention to additional supplements.
N-6 polyunsaturated fatty acids are widely present in food, there are many sources, although the human body needs, but in fact, in our daily diet, the intake of n-6 polyunsaturated fatty acids is often too high, and a large intake of n-6 polyunsaturated fatty acids is unhealthy for the body.
Health is most beneficial only when the intake of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids is balanced. Studies have shown that the ratio of n-6 and n-3 polyunsaturated fatty acids is best maintained between 1:1 and 4:1.
In summary, among the three fatty acids in the oil:
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 better than N-6 polyunsaturated fatty acids.
Therefore, when we choose edible oil, we should pay attention to the priority level of these fatty acids.
The difference between various food oils is mainly the composition of fatty acids
Common edible oils on the market can be divided into two categories: animal edible oils and vegetable edible oils. Animal edible oil comes from natural animal fat, common lard, butter, butter, etc., generally solid at room temperature.
Vegetable edible oil is derived from the fruits, seeds and germs of natural plants, commonly including soybean oil, peanut oil, rapeseed oil, sunflower oil, corn oil, olive oil, sesame oil.
Nutritional classification of common edible oils: data from the Dietary Guidelines for Chinese Residents (2022)
As can be seen from the figure above, animal edible oils belong to the category of high saturated fatty acids, and the cholesterol content is also high, and it is not recommended to consume excessively. But animal cooking 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, B12; Lard also helps clear the intestines and, for people with constipation, relieves constipation.
Foreign nutritionists have also found that animal edible oils also contain lipoproteins, which have the effect of prolonging life. Therefore, animal cooking oil is not completely inedible, but pay attention to control intake, and its calorie intake cannot exceed 10% of the total daily calorie intake.
Vegetable edible oil is rich in unsaturated fatty acids, so it is indeed a better choice to give preference to plant-based edible oil as daily cooking oil.
For other nutrients, advantages and disadvantages of several common plant-based cooking oils and which cooking method is suitable, we have also summarized them for you:
Eat cooking oil for a long time, do not eat the same one for a long time
Comprehensively considered, each variety of plant edible oil has its own unique nutritional value, so edible oil should be eaten differently, do not eat the same for a long time.
But for many families, buying oil is buying a large barrel, eating for months, and during these months, the proportion of the intake of three fatty acids is also unbalanced. When changing the oil, you also have to consider what oil to buy next time, and it is more troublesome to think about. In this case, blending oil is a better choice.
Blending oil is a cooking oil that is mixed and formulated according to the needs of these different vegetable oils. The ideal blended oil, through the ratio between different vegetable oils, makes the proportion of three fatty acids more healthy and balanced, and its overall nutritional value will be higher than that of a single variety of vegetable oil.
Although blended oil is a better choice, but also pay attention: the same blended oil only contains a specific number of vegetable oils, often eaten, the effect of diversification will not be particularly ideal, so even if you eat blended oil, it is recommended to change the variety, different varieties of blended oil to eat.
And blending oil also depends on which kinds of oils are blended with each other, if the proportion composition of the three fatty acids is out of balance, for example, the varieties involved in the blending are monounsaturated fatty acids and n-6 rich varieties, but lack of n-3 polyunsaturated fatty acids rich varieties. Or one of the varieties used to participate in the blending accounts for the vast majority, while the other varieties account for only a little.
Then long-term consumption of these blended oils can actually not achieve the effect of balanced intake of fatty acids.
The new national standard "National Standard for Food Safety Vegetable Oil (GB2716-2018)" requires that "the label identification of edible vegetable blending oil should indicate the proportion of various edible vegetable oils"[4], and we should pay attention to the proportion of each single variety of vegetable oil in the label. If there is also a proportion of various fatty acids, you can see whether its ratio is scientific.
The "Dietary Nutrient Reference Intake for Chinese Residents" recommends that in the oils and fats we consume, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids is less than 1:1:1. [2] Undoubtedly, this is the most scientific principle of oil use, and everyone must pay attention to it.
Here to remind everyone that some commercially available blended oils, their fatty acid ratio is not 1:1:1, everyone should pay attention to the ratio when buying.
No cooking oil is perfect. It is recommended that when buying edible oil, not only a single variety of edible oil should be changed, even if you buy blended oil, you should try to change the food. Mix and match often to eat nutritious and healthy.
Pay attention to these when purchasing and cooking cooking cooking oil
1. When purchasing edible oil
1.1 Look at the quality level
Edible oil is divided into 4 grades of first, second, third, and fourth grades (olive oil is a special case, divided into virgin olive oil: extra grade, intermediate grade, refining, blended). So is it that the higher the grade, the higher the quality of the oil? Not really.
The first and second edible oils have high purity, less impurities, clear color, lighter aroma and taste, less oil smoke when cooking, and are 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.
Third, fourth-grade edible oils are just the opposite, they have low purity, many impurities, darker color or appropriate turbidity, stronger aroma and taste, larger oil smoke when cooking, more suitable for low-temperature cooking. However, they have the advantage of retaining the nutrients in the oil to the greatest extent.
No matter what grade of oil, as long as it meets the national standards, it can be eaten normally. We can choose according to the need for nutrients, the need for flavor and different cooking styles.
1.2 Look at the processing technology
Pressing oil is a physical method of separating the oil from the raw material, retaining more nutrients, and the pressing process is more expensive and expensive. Leaching oil is a grease purified by a series of chemical processes, with high oil yield, low production cost and relatively cheap price.
Many people like to press oil and think it is healthier; I don't like leaching oil, I think chemicals will remain. In fact, there is no need to worry too much, as long as it is a edible oil that meets the national standard, choose a large brand of regular supermarkets to buy, it is safe and can be eaten with confidence.
However, it should be noted that do not buy bulk oil of unknown origin, and do not choose oil pressed by the soil method of small workshops.
1.3 Look at the production date and shelf life
The closer the production date, the better, and the farther the shelf life, the better. Generally, the shelf life of edible oil is 18~24 months, and it should be stored in a cool, dry, dark and sealed manner.
1.4 Try to buy small packages
After the edible oil is opened, it will undergo an oxidation reaction with the air, accelerating the deterioration of the oil. So try to buy small bottles of packaged cooking oil, cover the oil every time you use it, and it is best to use it 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 edible oil intake needs to be controlled between 25~30 grams, and this recommended value is recommended to be strictly observed for health reasons.
2.2 Control the cooking oil temperature
Do not wait until the oil smokes before putting ingredients in the cooking, 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 the cooking method
Use less cooking methods such as frying and frying. Frying and frying not only produce harmful substances including trans fatty acids, but also increase the intake of fat, and its aroma and taste also make us easy to eat too much, further causing metabolic diseases.
In fact, less oil can also cook delicious dishes, cooking methods should be steamed, boiled, stewed, stewed, stir-fried as much as possible, less frying, frying, can be used air fryer instead of frying.
2.4 Use new oil every time
Young families will save the oil after frying food, and continue to fry other foods or use it for stir-frying. However, repeated frying oil is easy to 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 is recommended to be used only once, and new oil is used every time the cooking oil is used.
Finally, I hope that after reading this content, you can have a clearer understanding of the selection and use of edible oil, so as to use oil and eat oil healthily!
Source: Popular Science China