Every time Po eats out, someone will point to the pig's trotters and politely say to the lady at the same table, "Eat more, girl, and it's beautiful." Because many people know that pig's trotters contain a substance called collagen, and collagen is the hottest new term for beauty nowadays. From cosmetics for external use, to oral capsules, to filling materials for plastic surgery, it can be seen everywhere. What exactly is collagen? What is its beauty secret? ■ Collagen loss and aging. Collagen is a kind of polymer protein, which can keep skin firm and elastic. It exists in human skin, bones, teeth, tendons and other parts. On the skin side, it forms a reticular support with elastic fibers, providing solid and powerful support for the dermis. With the increase of age, the content of human collagen will gradually lose, and the skin will lose its elasticity, become thinner and aging. Therefore, skin aging is indeed inextricably linked with the loss of collagen. Some foods containing colloid, such as beef tendon, pig's trotters, chicken wings, chicken skin, fish skin and cartilage, are rich in collagen, but your skin can't get much benefit from diet. ■ External use and internal use may not beautify the market. Collagen has various oral capsules and oral liquids. Experts believe that oral capsule (oral liquid) is collagen extracted from animal skin by hydrolysis. After oral administration, they only become amino acid "parts". Due to individual differences and actual needs, the animal collagen or amino acids that everyone eats will never be dominated by the subjective wishes of users. Therefore, the anti-aging effect of taking collagen skin care is obviously exaggerated. Moreover, the collagen in protein contained in daily diet is enough for the actual needs of human body, and it is unnecessary for healthy people and people with normal diet and nutrition to supplement collagen specifically. Aging is a natural law, and no measure can reverse it. We should realize this. There are also many skin care products about collagen on the market. Adding certain collagen or amino acids to cosmetics can protect the skin and resist aging, but this effect is temporary and will not be converted into its own collagen after long-term use. ■ Injection also has certain limitations. The most effective way to "directly supplement" collagen is to inject collagen extracted from the calf into the dermis like an injection in cosmetic medicine to repair static wrinkles, such as wrinkles around the lips, and scars and pits formed by collagen that hurts the dermis due to severe inflammation of acne (acne). However, there are some restrictions: 1. The effect is temporary. Collagen injected into the body will not stay in the dermis all the time, but will be slowly consumed and metabolized, so it can only last for about six months to a year, depending on the individual situation, and then it must be injected again. 2. The cost is high. The cost of several thousand yuan per injection is not affordable for every consumer. It may cause a few people to be allergic. Dermatologists suggest that people with allergies should take an allergy test first to ensure that there are no adverse reactions before inserting needles. ■ It is better to make up than to prevent. Because the existing methods of supplementing collagen are not very effective, experts believe that it is more effective to start with "prevention", that is, to slow down the loss and degradation of collagen. The first is sun protection. Dermatologists believe that more than 90% of premature skin aging is caused by improper sun exposure. Secondly, a balanced diet, especially eating more fruits and vegetables containing antioxidants, such as carrots, tomatoes and grapes, and drinking more red wine and tea, can protect collagen in the skin. Finally, don't forget to avoid eating high-fat food. Foods with high calorie and fat, especially fried foods, are prone to produce free radicals and accelerate aging.