People want to maintain their skin smooth and beautiful. However, it is normal for people to be troubled by various factors, such as wrinkles and spots. The foods containing chondroitin, nucleic acid, alkaline substances, and vitamins can effectively beautify the skin for people. 

The foods containing chondroitin like chicken skin can effectively enhance the elasticity of the human body. The human skin is composed of cuticular layer, corium and subcutaneous tissue. Among these three parts, corium is the most important aspect to affect the beautifying effect of the skin. Corium is composed of elastic fibers whose main composition is chondroitin. The lack of chondroitin can decrease the elasticity of the skin and cause wrinkles. Therefore, the adequate intake of the food containing chondroitin can defer the aging of the skin and enhance the elasticity.

The foods containing nucleic acid mainly include fish, shrimp, mushroom, honey and so on. These foods plays an important role in removing age pigment and deferring the aging. Therefore, people should increase the intake of nucleic acid and vitamin C so as to defer the skin aging and resist the formation of wrinkles.

The foods containing alkaline substances refer to vegetables, fruits, bean products and marine products. According to the medical research, the excessive intake of acidic food can make the blood inside the human body become acid and increase the contents of lactic acid and uric acid. These two substances can come to the skin surface with sweat to decrease the elasticity and activity of the skin. However, the intake of alkaline food can make the blood become alkalescent and at the same time, the contents of lactic acid and uric acid can be decreased to reduce the harms to the skin.

The foods containing collagen like soft-shelled turtle and pig skin can strengthen the skin function of storing water and nourish the skin. The medical research proves that the content of collagen contained in pig skin is much higher than that contained in pork. Collagen is the main composition for the growth of the skin. It plays an important role in reducing even removing the wrinkles.

The foods containing vitamins and trace elements are rather beneficial to the human skin. For example, vitamin A can keep the skin smooth and soft and trace elements like iron and copper can nourish the skin and prevent the formation of wrinkles. Therefore, it is reasonable for people to increase the supplementation of vitamins and trace elements.