Views:0 Author:Site Editor Publish Time: 2021-08-20 Origin:Site
Folic acid is a water-soluble vitamin, C19H19N7O6. It is so named because it is abundant in green leaves. It is also known as pteryl glutamate. It occurs in several forms in nature and its parent compound is a combination of teridine, p-aminobenzoic acid and glutamic acid.
Folic acid contains one or more glutamyl groups and most naturally occurring folic acid is in the polyglutamic form. The bioactive form of folic acid is tetrahydrofolate. Folic acid is a yellow crystal, slightly soluble in water, but its sodium is easily soluble in water. Insoluble in ethanol. Easy to destroy in acidic solution, is not stable to heat, at room temperature is easy to lose, see light is easy to be destroyed.
Folic acid in the body has two ways of active absorption and diffusion passive absorption, the absorption site is mainly in the upper small intestine. The absorption rate of reduced folic acid is higher, the absorption rate of glutamyl is lower, glucose and vitamin C can promote absorption. After absorption, folic acid is deposited in intestinal wall, liver, bone marrow and other tissues in the body, and is reduced by folic acid reductase with NADPH to physiologically active tetrahydrofolate (THFA or FH4), which is involved in the synthesis of purine and pyrite. Therefore, folate plays an important role in protein synthesis, cell division and growth, and promotes the formation of normal red blood cells. Deficiency can lead to reduced hemoglobin production in red blood cells and blocked cell maturation, leading to megaloblastic anemia.
Folic acid is widely distributed in green leafy plants, such as spinach, beets, and broccoli. It is also found in animal foods (liver, kidney, egg yolk, etc.), fruits (citrus, kiwi, etc.), and yeast, but to a lesser degree in root vegetables, corn, rice, and pork. However, among these green leafy vegetables, the folic acid content is higher mainly in Dongfeng cabbage, horse chestnut leaf, Shanshanzizi cabbage, Artemisia willow bud, spicularia spiculata bark, wild asparagus, the contents are respectively 36.195, 23.478, 20.137, 67.600, 59.553, 22.032ug /g.
Folic acid in the form of polyglutamate that enters the body must be broken down into free folic acid before it can be absorbed by the body. It is γ -L-glutamyl carboxypeptidase in the epithelium of small intestine that hydrolyzes polyglutamic acid folate. Folate-binding proteins play a key role in the digestion, distribution and storage of folic acid. Folate-binding proteins have been discovered in three categories: high-affinity folate-binding proteins, membrane-related binding proteins, and cytoplasmic binding proteins. The high affinity folate binding protein protects the stable presence of folate in the blood and may also control the specificity of the distribution of folate in the plasma.
In general, normal people need 100~200 μg/d, and the world Health Organization recommends 200 μg/d for adults and 400 μg/d for pregnant women and nursing mothers. The FDA's new dietary guidelines for folic acid are: 240 μg/d for men aged 25 to 50 years; Between 25 and 50 years old (female), 190 μg/d; For nursing mothers and pregnant women, 400 μg/d; For infants, it was 200-400 μg/d.