Yellow mustard can provide some protein, fiber and vitamins -- such as vitamin C and many of the B-complex vitamins. It is particularly rich in several minerals that are important for good health. Be careful, however, not to consume too much of it; yellow mustard is also high in sodium, which can increase your risk of heart disease if consumed in excess.
One tablespoon of yellow mustard contains 21 mg of potassium. According to the University of Maryland Medical Center, your system needs potassium to send electrical signals inside your body, to contribute to digestive health and a steady heartbeat, and to allow the muscles to contract properly. Most adults need an intake of about 2,000 mg of potassium per day.
There are also 16 mg of phosphorus in each tablespoon of yellow mustard. It is a mineral that contributes primarily to the development of strong teeth and bones, but it is found in every single cell of the body. It contributes to the body's usage of protein, carbohydrates and fats, to kidney and heart function, and to the processing of the B-complex vitamins, among other purposes. According to National Institutes of Health online medical encyclopedia Medline Plus, adults need about 700 mg of phosphorus per day.
In addition to phosphorus, the other mineral your body primarily uses to build your teeth and bones is calcium. It also contributes to muscle and nerve function. Each tablespoon of yellow mustard contains 9 mg of calcium. According to the National Institutes of Health Office of Dietary Supplements, adult men need 1,000 mg of calcium per day; adult women need 1,000 mg per day until age 50, and 1,200 mg per day thereafter.
The tablespoon of yellow mustard also provides 7 mg of magnesium. Your system needs magnesium for such purposes as processing and using energy in the form of ATP molecules. According to the Linus Pauling Institute at Oregon State University, a typical adult male needs 400 to 420 mg of magnesium per day, while a typical adult female needs 310 to 320 mg of magnesium per day.