Vitamins(to be) substances that your body(to need) to grow and develop normally. there(to be) 13 vitamins your body(to need). each (to have) specific jobs. if you(to have) low levels of certain vitamins, you(to develop) a deficiency disease. for example, if you(not to get) enough vitamin d, you might develop rickets. some vitamins(to help) you to prevent medical problems. vitamin prevent) night blindness. the best way to get enough vitamins is to have a balanced diet with a variety of foods. in some cases you(to need) to take a daily multivitamin for optimal health. however, high doses of some vitamins(to lead) to health problems too .