We all know that a diet rich in calcium is required to keep our teeth strong and healthy, and that plenty of vitamin C is required to ward off scurvy. However, there are a wide range of more obscure vitamins and minerals just as important when it comes to maintaining a healthy mouth, including some that a lot of people may not even be aware of. The following list contains just some of these lesser-known nutrients, so be sure to consult your dentist and/or nutritionist on what you should be eating to take optimal care of your mouth.

Phosphorus 

Aside from calcium, phosphorus is the most abundant mineral present in the body, and while you might be more used to seeing it stuck to the heads of matches, it plays a vital role in many of the body's everyday functions. One of the most important roles it plays is in the proper formation and maintenance of teeth — calcium needs to be chemically bound to phosphorous by the body before it can be used to strengthen teeth, and without enough phosphorus to process it the body will expel calcium as a waste product.

Milk and other dairy products contain copious amounts of phosphorus as well as calcium, so phosphorus deficiency is quite rare and generally restricted to vegans and people who take calcium supplements in lieu of calcium-rich food. Other rich sources of phosphorus include citrus fruit, fish, nuts (especially almonds) and tomatoes.

Folic acid

You've probably heard the mainstream press talk endlessly about how important folic acid is to pregnant mothers, but it's also required for healthy gums. This acid is essential for the body's natural replenishment of gum tissue as it is lost, and low levels of folic acid have been linked with an increased risk of developing periodontal disease and gingivitis. Folic acid can also help to prevent painful mouth and tongue ulcers.

Sources of folic acid include leafy greens such as kale and spinach, and cruciferous vegetables such as broccoli and sprouts. Citrus fruits, beans and legumes are also rich in folic acid. Cooking tends to destroy much of a food's folic acid content, so try to eat your sources of folic acid raw when practical (such as a leafy green salad). You can also find mouthwashes containing folic acid, which are useful for treating mouth ulcers.

Vitamin A

Most people who are aware of vitamin A's importance generally associate it with healthy skin, but they may not realise that the vitamin is also required to keep the mucous membranes inside the mouth healthy too. Without a healthy supply of vitamin A in the diet, the replacement of the cells that form the lining of the mouth and tongue is interrupted, leading to a range of conditions including dry mouth, infection of the salivary glands, canker sores and gum disease. Lack of vitamin A in children may also be associated with abnormal tooth formation.

Vitamin A is present in large quantities in carrots, pumpkin, liver, leafy greens and sweet potatoes. However, bear in mind that excessive vitamin A consumption carries a range of nasty side effects, including fatigue, vomiting and even liver damage. Don't take supplements unless your diet is extremely low in vitamin A.