Fruit and vegetable anti-cancer experts

2017-03-22

Source: Health News

Chinese Academy of Medical Sciences Institute of Medicinal Research researcher Guo Jia

      Natural pigment carotene

      Vegetables and fruits are the main source of food for carotene. Compared with another class of natural pigment anthocyanins, carotene has good thermal stability and is not susceptible to damage during cooking and processing.

      Carotene is the largest number, the most widely distributed class of natural pigments, the species is currently known to have 563 species. Carotene is mainly produced in the plant, its function is to assist chlorophyll photosynthesis, to prevent the damage of chloroplast light and affect the smooth progress of photosynthesis, and to attract insect pollination, indicating fruit ripening and tree leaves grow old.

      Nutritional function of carotene

      The most well-known carotene function of vitamin A is that it can be converted into vitamin A in the human body.

      In the gut and liver cells of humans and animals, other carotenoids with a β-violet ketone ring structure can be converted to vitamin A in addition to carotenoids with two β-violet ketone cyclic structures. There are 50 kinds of carotenoid molecules, of which 20 are present in the appearance of red, yellow and dark green vegetables and fruits. These carotenoids (such as alpha-carotene, gamma-carotene and zeaxanthin) can be converted to vitamin A.

      Vitamin A can maintain normal night vision and prevent dry eye disease, in the body's metabolic process also plays an important role.

      Scavenging free radicals In carotenoid molecules, there are a large number of conjugated systems formed by double bonds. When the free radicals in the human body meet with carotenoids, they generate stable carotenoid free radicals, convert the original free radicals into stable compounds, or react with free radicals to produce stable carotenoid free radicals. The low reactivity of carotenoid free radicals has no damaging effect on other molecules in the human body.

      When two carotenoid free radicals meet, they combine to produce stable dimeric carotene. Or two carotene free radicals encounter disproportionation reaction, respectively, to generate a common carotene molecule and a three-button carotene molecules. So, carotene can remove free radicals, is conducive to the prevention of a variety of cancer.

      Antioxidant Compared to other molecules that make up the cell, the stability of the carotene molecule is much lower and is therefore more likely to react with reactive oxygen species. It is because the carotene can be the first oxidation reaction and the consumption of reactive oxygen, which makes the other molecules of cells from the destruction of reactive oxygen species. This is the antioxidant effect of carotene. To cardiovascular disease, for example, its occurrence is caused by oxidative damage caused by low-density lipoprotein, and with the blood circulation of carotene can protect low-density lipoprotein from reactive oxygen damage.

      A few people add carotene to ineffective

      According to long-term observation, nutritionists have been questioning people's ability to absorb carotene and convert carotene into vitamin A. But by the conditions of the restrictions, the previous study has not yet come to a clear conclusion.

      From the mid-90s of the last century, the United States Department of Agriculture Agricultural Service Bureau of Western Human Nutrition Research Center, Barry and the University of California scholars, the use of high performance liquid chromatography and gas chromatography-mass spectrometry, with radioactive carbon atom labeled β - carotene in the body to absorb and metabolic process, and get the following two clear conclusions:

      The first conclusion is that although a carotenoid molecule can be converted into two molecules of vitamin A from a chemical structure, the human body does not convert a carotenoid molecule into two molecules of vitamin A.

      The second conclusion is that although the ability of most people to absorb and utilize carotene is similar, few people not only have low absorption capacity of carotene, but also have lower ability to transform and utilize carotene.

      The above conclusions clarify that carotenoids are added to people who lack vitamin A in sub-Saharan and South America in Southeast Asia, but they can not prevent the cause of blindness caused by dry eye. Therefore, for this part of the people, only to eat more rich in vitamin A meat, eggs and the whole dairy products, in order to ensure good health.