As we all know, vegetables, especially colored vegetables, are rich in vitamins, so vegetables are one of the main sources of the vitamins needed by human body. In our life, when the intake of vegetables is limited, many people would take vitamin preparations to supplement the vitamins; while a lot of other people think that vegetables are rich in vitamins, so there is no need to take vitamin preparations. Both of the two opinions are one-sided, because vegetables and vitamin preparations can not replace with each other.

On the one hand, vitamins can not replace vegetables.
This is because that the vitamins in vegetables are natural ingredients, while vitamin preparations are mostly synthetic, so they are different in nature. Secondly, vegetable is a collection of multi-vitamins, while vitamin preparation only contain one single kind of vitamin (of course there are exceptions). In addition, vegetables contain some natural substances, which are not vitamins itself, but play the similar effects as vitamins, such as bioflavonoid and chlorophyll. As a result, the healthy effect of vegetables is more comprehensive than vitamin preparations.

In addition, as for the prevention of cancer, vitamins also can't substitute for vegetables. It has been recognized by the nutrition experts around the world that eating more vegetables can prevent many types of cancer. However, whether taking in vitamin preparations can prevent certain types of cancer still hasn't been proved.

On the other hand, vegetables are not a substitute for vitamin preparations.
Take vitamin C as an example. Firstly, not all kinds of vegetables are rich in vitamin C, unless you carefully choose the green, red and purple vegetables and fruits, including red pepper, spinach, tomatoes, bitter melon and strawberries, oranges, kiwi fruit, etc, otherwise, it would be difficult to meet the daily needs of 100 mg of vitamin C. And this is the reason why there is about 30% of the population in our country who lack of vitamin C.

Secondly, vitamin C is a water-soluble component, which is easy to lose when it is washed. High cooking temperature or long time heating will also destroy a lot of vitamin C in the vegetables. What's more, vitamin C is also easy to be oxidized by the oxygen in the air, which will cause a great loss of vitamin C. So, unless with the correct cooking methods, otherwise, even you choose the vegetables containing plenty of vitamins, it is difficult to meet the daily needs of 100 mg vitamin C.

From this we can see, vegetables and vitamin preparations play different functions and have their specific effects on human health, so they can not replace with each other.