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Recently, trans fats (also known as "trans fatty acids") have once again been on the hot search. Some bloggers posted on the Internet that the "edible oil products" contained in some dairy products are trans fatty acids, which are not recommended for children; Some bloggers have collected "common aliases for trans fatty acids", including edible hydrogenated oil, margarine, margarine, etc., to remind parents to avoid products containing these raw materials; Some bloggers say that trans fatty acids are semi-permanent fats, and it takes the human body fifty or sixty days to metabolize them......
Not to mention the quality of the relevant products, just look at the "introduction" of some bloggers, and you will find that misunderstandings and rumors about trans fats have come again.
Are trans fatty acids scary? It's all in breast milk!
Some bloggers refer to trans fats as "deadly substances" and say that children should never touch them. As everyone knows, there are trans fats in breast milk.
As early as 2012, the National Expert Committee on Food Safety Risk Assessment issued a technical report on the dietary income level and risk assessment of trans fatty acids of Chinese residents (hereinafter referred to as the "technical report"), which introduced various knowledge of trans fatty acids in detail and pointed out that the health risk of trans fatty acids in the diet of mainland residents is very low.
The report of the authoritative body explains in detail the intake of trans fatty acids by mainland residents
According to a number of registered dietitians in China, according to the report and daily habits, the public does not need to "talk about trans fat discoloration".
Let's start with what trans fatty acids are.
Fats are triglycerides formed from fatty acids and glycerol, and have different names depending on the structure. Trans fatty acids are a type of fatty acid and belong to unsaturated fatty acids.
Many people think that trans fatty acids are a product of the food industry, but in fact, trans fatty acids are also found in natural foods, including dairy and related products of ruminants such as cattle and sheep. In human breast milk, trans fatty acids are also present. Studies have found that the trans fat content of breast milk accounts for between 1% and 10% of the fat content of breast milk.
Therefore, it is unrealistic to want to avoid trans fatty acids completely.
Do Chinese eat more trans fatty acids?
Let's look at the dangers of trans fatty acids.
Trans fatty acids are really bad for health. Studies suggest that trans fats significantly increase the risk of cardiovascular disease, increasing the risk of arteriosclerosis and heart attack.
But this does not mean that trans fat will be deposited in the body and cannot be metabolized, nor is it said on the Internet that "it needs to be metabolized in the human body for fifty or sixty days". In the human body, trans fats are metabolized in the same way as ordinary fats, except that they are "bad fats", and eating too much of them will increase health risks.
However, "talking about toxicity regardless of dosage is a hooligan". Whether trans fatty acids are harmful to health depends on intake.
At present, the dietary guidelines of the World Health Organization (WHO), the mainland, the United States and other countries all recommend that the energy supply ratio of trans fats should be less than 1%. For an adult who consumes 2,200 kcal per day, this is equivalent to eating 2.2 grams of trans fats per day.
The trans fat content of liquid milk averages 0.08g/100g, which means that a person has to drink 2.75 kg of milk a day before they consume more trans fat than the official recommendation. Obviously, this is not in line with everyday habits.
It is also said that in addition to naturally occurring trans fats, there are also trans fats in food processing, which are high in content, will they lead to excessive intake?
Don't worry too much either.
According to a survey by the National Expert Committee on Food Safety Risk Assessment, the per capita intake of trans fats in China is 0.39 g/day, accounting for 0.16% of total energy. Among them, the intake of residents in large cities is higher than that in small and medium-sized cities and rural areas, with an average intake of 0.55 g/day, accounting for 0.30% of the total energy.
It can be seen that the intake of trans fatty acids in mainland China is significantly lower than the official recommended value, and the public does not need to panic too much about trans fats.
Why hydrogenated vegetable oil,
Is the trans fat content of food still zero?
Although there is no need to "talk about trans fat discoloration", it must be noted that trans fats do exist in food industry products such as hydrogenated vegetable oil, margarine, and non-dairy creamer, and the content is higher than that of trans fats naturally occurring in food.
For example, in the ingredient list of biscuits and pastry products, "hydrogenated vegetable oil" can often be seen. It was born because the shortening effect of liquid vegetable oil is not good, after hydrogenation, the melting point of the oil increases, and it is semi-solid at room temperature, so as to meet the process and taste requirements.
In the case of incomplete hydrogenation of vegetable oils, some of the double bonds of fatty acids will change from the natural "cis structure" to the "trans structure", thus becoming trans fats.
However, this also means that not all hydrogenated vegetable oils contain trans fatty acids, and only incompletely hydrogenated oils and fats produce trans fats.
Nowadays, with the development and innovation of food science and technology, the trans fats in edible oil products such as hydrogenated vegetable oil can be well controlled, and there are also oil products using non-hydrogenated processes, which makes the trans fats contained in many hydrogenated vegetable oils, non-dairy creamers, cocoa butter substitutes and other products have decreased significantly, and even achieved "zero trans fats".
According to the national standard, if the food contains or partially hydrogenated oils and fats are used in the production process, the relevant raw materials must be marked in the ingredient list, and the trans fatty acid content must be indicated in the nutrition facts list. However, if the trans fatty acid content in 100 grams of food is less than 0.3 grams, it can be labeled as "0".
Some food ingredients contain edible fats and oils, but the nutrition facts list shows that the trans fat content is 0
So, if you see that the food ingredient list contains hydrogenated vegetable oil, margarine, non-dairy creamer, etc., don't be nervous, but pay attention to the nutrition facts list of the product and choose those products with low or "0" trans fatty acid content.
The most common source of trans fats turned out to be this!
Many consumers feel that if they do not choose foods containing ingredients such as hydrogenated vegetable oil, margarine, and non-dairy creamer, they can reduce their intake of trans fats as much as possible. This is also a misconception.
According to the technical report, the main source of trans fatty acids consumed by mainland residents is vegetable oil.
Gu Zhongyi, director of the Beijing Dietitians Association and a registered dietitian in China, explained that this is because as the oil temperature rises, trans fatty acids may be produced in various vegetable oils, and the amount of production increases with the extension of cooking time.
It is important to know that when vegetable oil smokes, the oil temperature is mostly above 200 °C: if it is a first-class oil, the smoke point of soybean oil is 225.8 °C, rapeseed oil is 215 °C, corn oil is 221 °C, and peanut oil is 192 °C...... At such high temperatures, even if it is only heated for a short time, trans fatty acids may be produced.
Therefore, to avoid excessive intake of trans fatty acids, first of all, pay attention to controlling the temperature and amount of vegetable oil in cooking, change cooking habits, reduce the amount of oil used, and avoid burning the oil until it smokes before starting cooking.
Experts remind that for leafy vegetables, sliced or shredded vegetables, you can stir-fry quickly on the premise that the oil does not smoke, or use the method of "water and oil stewing" - put the vegetables in a boiling oil-water mixture and stir-fry. For fried and grilled foods, limit the frequency of consumption and serve them with fresh fruits and vegetables.