There are various causes of yellowing teeth including genetics and not seeing your dentist regularly for a professional clean. One of the biggest causes is food. The foods that stain your teeth are:

– Drinks: black tea, coffee, and red wine contain tannins that adhere to your teeth

– Acidic foods: these will attack and wear away the surface enamel

– Deeply-hued foods: this includes very red foods such as berries, beetroot, and tomatoes.

“Tooth enamel is porous and can easily be stained, although fortunately, many of these stains are just on the surface and can be removed through regular brushings and professional teeth cleanings.”

Learn more about this topic here: https://yourdentalhealthresource.com/why-are-my-teeth-turning-yellow/