葉酸是一種水溶性B族維生素,，孕婦對葉酸的需求量比正常人高4倍,。孕早期是胎兒器官系統(tǒng)分化，胎盤形成的關鍵時期，細胞生長,，分裂十分旺盛,。此時葉酸缺乏可導致胎兒畸形．如在中國發(fā)生率約為3.8‰的神經(jīng)管畸形,，包括無腦兒,，脊柱裂等。另外還可能引起早期的自然流產(chǎn)。到了孕中期,，孕晚期,，除了胎兒生長發(fā)育外，母體的血容量,，乳房,，胎盤的發(fā)育使得葉酸的需要量大增。葉酸不足,，孕婦易發(fā)生胎盤早剝,，妊娠高血壓綜合征，巨幼紅細胞性貧血,；胎兒易發(fā)生宮內(nèi)發(fā)育遲緩,，早產(chǎn)和出生低體重，而且這樣的胎兒出生后的生長發(fā)育和智力發(fā)育都會受到影響,。

準備受孕之前,，準媽媽準爸爸除了基本的戒煙、戒酒之外,，還必須保持一份愉快的心情,，準備懷孕的女性們，應在懷孕前就開始每天服用400μg的葉酸,。美國研究人員調(diào)查發(fā)現(xiàn)，女性如果在懷孕初期就開始補充葉酸,，可降低將來嬰兒出現(xiàn)唇裂的幾率,。另外，懷孕期的準媽媽們,，正確地攝取維他命是很重要的,，復合維他命（含豐富的維他命A、B6,、B12,、C、葉酸）和綜合礦物質（要含有1000mg的鈣,、500mg的鎂）,，對預防寶寶的腦部、神經(jīng)缺陷也非常重要,。

生理功能
1）作為體內(nèi)生化反應中一碳單位轉移酶系的輔酶,，起著一碳單位傳遞體的作用。

2）參與嘌呤和胸腺嘧啶的合成,，進一步合成DNA和RNA,。

3）參與氨基酸代謝，在甘氨酸與絲氨酸,、組氨酸和谷氨酸,、同型半胱氨酸與蛋氨酸之間的相互轉化過程中充當一碳單位的載體,。

4）參與血紅蛋白及甲基化合物如腎上腺素、膽堿,、肌酸等的合成,。

葉酸對蛋白質、核酸的合成及各種氨基酸的代謝有重要作用,。

參與嘌呤和嘧啶合成:作為輔酶參與核酸合成中嘌呤和嘧啶的形成,，在細胞DNA合成中發(fā)揮作用。

參與氨基酸相互轉化:參與二碳氨基酸和三碳氨基酸相互轉化,。促進了苯丙氨酸與酪氨酸,，組氨酸與谷氨酸，半胱氨酸與蛋氨酸的轉化,。此外,，葉酸還是含鐵血紅蛋白的組分。

建議用量：通常情況下為400微克,，但酗酒,、抽煙、口服避孕藥或孕期,，葉酸需求量會加大,。
一般每天需要補充800微克：每天每餐1粒

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Folic acid is part of a group of water soluble B vitamins . It is also known as folacin or folate. The name comes from the Latin word folium - leaf and was first discovered in the 40s extracted from spinach. It should be renewed every day, because the body does not stores it for a long time. Folic acid is very important for women of childbearing age, as low levels can lead to serious consequences for the fetus such as spina bifida. Low levels of folate are associated with an increased risk of heart disease due to the elevated homocysteine. Folic acid deficiency is the most common deficiency of a particular vitamin in the world. Half of its amount in food is lost due to cooking, processing or short-term storage, so it is highly recommended to take folic acid supplements.

Advantages:

Necessary for the production of DNA and RNA
Required for proper cell division and transmission of genetic code to the newly formed cells
important for the production of red blood cells, proteins and certain amino acids
Very important for closing the neural tube during pregnancy, preventing defects such as spina bifida
May affect cervical dysplasia and reduces the need for hysterectomy
Useful for people with depression and / or schizophrenia
Folate, vitamin B12 and vitamin B6 support cognitive ability of older people
Promotes healthy immune system
May reduce the development and progression of atherosclerosis
May affects inflamed gums and gingivitis

Recommended dosage:

The reference values of the diet are 400mcg, though, for people who use alcohol, cigarettes, oral contraceptives or during pregnancy, should be increased.
A typical daily dose is 800 mcg:
Take 1 tablet daily with food.