Beware of hidden health risks in food: Understanding and controlling the risks of trans fatty acids and cholesterol
4. Trans fatty acids
Before the fall of 2010, the term "trans fatty acids" was still unfamiliar to some food companies and consumers in China. Hydrogenated oils widely used in foods such as biscuits and cakes contain large amounts of trans fatty acids, which are very harmful to human health... This attracted widespread attention. Some people even regarded it as a "poison," and it seemed that overnight everyone was against it, and everyone was on high alert. So how should we view the issue of trans fatty acids?
(1) What are trans fatty acids? Most unsaturated fatty acids in nature have a cis configuration, meaning that the two hydrogen atoms at the unsaturated double bond are in the same direction. When vegetable oil is treated with a catalyst, hydrogen is added to the double bond positions of the unsaturated fatty acid, causing the two hydrogen atoms to be in opposite directions, resulting in trans fatty acids. After hydrogenation, some of the saturated fatty acids in vegetable oil are converted into trans fatty acids. The original liquid oil undergoes a physical change, becoming a solid or semi-solid state, which facilitates storage and transportation and extends shelf life. Hydrogenated oils have good shortening properties, optimizing the taste and flavor of food, and are therefore widely used in food production.
(2) The health effects of trans fatty acids. Studies have found that trans fatty acids can increase serum total cholesterol and low-density lipoprotein cholesterol (bad cholesterol) and decrease high-density lipoprotein cholesterol (good cholesterol), thereby increasing the risk of cardiovascular disease and causing greater harm than saturated fatty acids. (3) International management measures. The WHO recommends that the energy obtained from trans fatty acids should not exceed 1% of the total dietary energy per person per day. If calculated based on an adult's daily energy intake of 2000 kcal, the daily intake of trans fatty acids should not exceed 2.2 grams.
(4) Opinions of some experts and work done by government departments in my country. Trans fatty acids are a component in food that is detrimental to health and should be consumed in moderation. With the trend of Westernization in the diet of Chinese residents, the issue of trans fatty acids should also be taken seriously. The Ministry of Health has organized and carried out risk monitoring and assessment of trans fatty acids. In the national standard for infant formula issued in 2010, it was stipulated that hydrogenated oils should not be used in raw materials, and the maximum content of trans fatty acids in the final product should be less than 3% of the total fatty acids. (5) Foods with high trans fatty acid content include: egg yolk pies, cream cakes, puff pastries, cookies, wafer biscuits, sandwich biscuits, high-fat bread, milk tea, coffee creamer, etc.
(II) Lipids
Among lipids, cholesterol, a type of sterol, is most closely related to our diet. Cholesterol plays an important physiological role in the human body. It is an essential component of cell membranes and nerve fibers, and a raw material for the synthesis of vitamin D₃, bile acids, sex hormones, and adrenocortical hormones. Cholesterol in the human body comes from two sources: one is synthesized internally, and the other is ingested from food. Excessive cholesterol intake will raise blood cholesterol levels, leading to atherosclerosis and coronary heart disease. Individual sensitivity to the effects of dietary cholesterol on blood lipid levels varies.
Cardiologists and nutritionists recommend that adults limit their daily cholesterol intake to less than 300 milligrams. If you already have dyslipidemia, you should limit it even further, to less than 200 milligrams. Cholesterol is only found in animal-based foods, with high levels in organ meats and egg yolks. For example, 100g of milk contains 15mg, lean pork contains 80mg, pork liver contains 288mg, eggs contain 585mg, egg yolks contain as much as 1510mg, and beef brain contains as much as 2447mg.