In order to prevent the occurrence of yellowish light gray or dark gray teeth, pregnant and lactating women, as well as children under 8 years of age should not use tetracycline drugs, and control the amount of fluoride in drinking water. It is advisable to eat foods with high fiber in the diet; foods with high vitamin C content; and foods containing citric acid. Avoid eating food containing melanin; avoid eating food containing strong acidity; avoid eating food containing high fiber. 1, drink less black tea or black tea Tea has a large number of polyphenol oxides, long-term tea consumption, will make the teeth yellow. Studies have found that the highest tea polyphenol oxides in black tea, followed by black tea, Pu-erh tea, barley tea in the lowest polyphenol oxides content, you can rest assured that you can drink In addition, the longer the time to cook the tea leaves, the lower the role of oxides, in order to ensure that you have a mouthful of white teeth, you can properly extend the time to cook the tea. 2, eat less curry in the American Dental Association’s newly released “teeth staining list”, curry’s main ingredient turmeric over nicotine, ranked first, the biggest impact on the color of teeth. Research has pointed out that the role of turmeric on teeth staining is almost irreversible, is a veritable “white teeth nemesis”. If you really like that kind of spicy feeling, it is recommended that you choose the green curry with the weakest staining effect, and avoid the red curry and yellow curry with stronger effect. 3, less drug toothpaste As the saying goes, “medicine is three times poisonous”, although the drug toothpaste can control the production of pathogenic bacteria, but it will also destroy the “ecological balance” in the oral cavity, triggering new infections. More importantly, the alkaloids in the drug toothpaste will damage the enamel on the surface of the teeth, so that the teeth lose their luster. 4, drink less mineral water Fluorine on the one hand can increase tooth enamel, make it stronger, on the other hand, will make the teeth gradually become yellow. Mineral water contains a lot of fluorine, drink too much, will make your mouth of white teeth lose color! The United States oral health expert’s advice is: each person drink at least 1000 milliliters of white water per day, including mineral water intake should not exceed 300 milliliters, the remaining 700 milliliters, you can drink pure water or boiled tap water. 5, drink less Coke Coke is composed of syrup and carbon dioxide gas, drink too much, will make the sugar deposited on the surface of the teeth, so that its color becomes black. A study found that if you drink 1 liter of Coke every day, the enamel on the surface of your teeth will be half eroded by acid after two years. Among carbonated beverages, dark colas are the most damaging to teeth, followed by orange sodas. Generally speaking, the lighter the color, the safer the drink, and it is recommended that you choose clear-colored Sprite.