填空题 Vitamin is an important topic on health and 1 . Vitamins are natural 2 substances that we need in order to stay healthy. To get enough vitamins, we must vary our 3 with many types of meat, 4 , fruits and such the like. 5 of vitamins is not a great problem, except for Vitamin B and C. Vitamin A is important for 6 and eyes, and people lacking this vitamin may suffer from 7 problems. Vitamin B is actually a group of many vitamins called the Vitamin B 8 . It is necessary for regulating the 9 system of the body and without it you may encounter 10 and confusion. Vitamin C helps maintain a 11 within the body that assists in the formation of teeth and 12 . It is also good for boosting the 13 system and is needed to absorb 14 into the blood. The body can produce Vitamin D, when it is exposed to 15 . Vitamin E is known to be an essential 16 in over 20 vertebrate species. It also helps to carry 17 in the blood. We need vitamins to maintain a healthy 18 , but there is still controversy over the real effect of multivitamins or vitamin 19 , and 20 of vitamins can be potentially harmful to human health.