Citrus fruit is the largest family of fruits, including orange, grapefruit, grapefruit, kumquat, lemon and other varieties. Oranges are traditionally regarded as the main source of vitamin C in Western diet, it can also provide a considerable amount of carotene and minerals such as potassium, calcium, and iron. Citrus fruits can resist oxidation, strengthen the immune system, inhibit the growth of tumor cells, and make tumor cells into normal cells. Australian scientists say that among all fruits, citrus contains more than 170 kinds of phytochemicals, including more than 60 kinds of flavonoids and 17 kinds of carotenes. Flavonoids have the effects of anti-inflammatory, anti-tumor, strengthening blood vessels and inhibiting blood coagulation, carotenoids have the antioxidant effects and so on. These comprehensive physiological active ingredients make citrus fruits have inhibitory effect on many kinds of cancer.

In fact, the content of each nutrient is not always high in citrus fruit. In terms of potassium, magnesium, iron and other mineral content and vitamin C content, it is not as good as fresh jujube; in terms of flavonoids content, it is not as good as hawthorn, papaya and mango. However, citrus fruits are abundant in yield, cheap in price and edible in all seasons, so people pay more attention to the nutritional significance of citrus fruits in diet. The peel of citrus fruits contains a lot of pectin, among which the aromatic oil has an appetizing effect, the peel of orange petals contains a large amount of dietary fiber, and citrus has the effect of relieving cough and resolving phlegm. However, it does not mean that people who don't cough and have phlegm also have to eat orange peel and orange collaterals.

Citrus fruits should not be eaten too much. Only on the basis of nutritional balance, the promotion effect of various foods on health can be fully reflected. If eating too much citrus fruits, there would be a risk to suffer from "orange peel disease" which can make people's skin turn into yellow. Eating a lot of citrus fruits can also stimulate the stomach.

Finally, if you only drink orange juice, the health effect of orange will be greatly reduced. Because in the process of squeezing orange to get orange juice, the vitamin C, flavonoids and carotenoids are lost a lot, while pectin and fiber are almost all lost. Of course, oranges are seasonal fruits, which are not convenient for preservation. Through the joint research of medical experts, the effective ingredients of oranges are retained through the extraction process, so the orange extract appears.