葉酸:用途、益處和副作用

Uses and effectiveness

  • Folic acid deficiency. Taking folic acid can improve folic acid deficiency.
  • High levels of homocysteine ​​in the blood (hyperhomocysteinemia). This condition is related to heart disease and stroke. Oral folic acid can reduce homocysteine ​​levels in people with normal or high homocysteine ​​levels and in patients with renal failure.
  • Toxicity caused by the drug methotrexate. Oral folic acid seems to reduce nausea and vomiting caused by methotrexate treatment.
  • For birth defects of the brain and spinal cord (neural tube birth defects). 600-800 micrograms of folic acid by mouth during pregnancy can reduce the risk of these birth defects. Folic acid can come from diet or supplements. Some high-risk groups should consume 4000-5000 micrograms per day.
  • The memory and thinking ability of the elderly decline. Oral folic acid, whether taking other supplements or not, can improve the memory and thinking ability of the elderly, whose thinking ability declines more than expected at that age. But it does not seem to apply to older people who are experiencing a decline in their thinking ability commensurate with their age.
  • depression. Oral folic acid and antidepressants seem to improve the symptoms of some patients with depression.
  • hypertension. Taking folic acid by mouth, lower blood pressure daily for at least 6 weeks. Some people with high blood pressure who have not taken other antihypertensive drugs.
  • Swollen gums caused by phenytoin. Applying folic acid to the gums seems to prevent this problem. But oral folic acid does not seem to help.
  • Stroke. In areas of the world where folic acid is not added to cereal products, taking folic acid supplements can reduce the risk of stroke. But for people living in countries where folic acid is added to cereal products, supplements do not seem to help.
  • A skin-induced leukoplakia develops on the skin (vitiligo). Oral folic acid seems to improve the symptoms of this condition.

May not work

  • Low levels of healthy red blood cells due to iron deficiency (anemia). Adding folic acid to iron supplements does not treat anemia better than taking iron supplements alone.
  • cataract. Oral folic acid and vitamin B6 and vitamin B12 cannot prevent cataracts. In fact, it may increase the number of cataracts that need to be removed.
  • diarrhea. Oral folic acid does not seem to prevent diarrhea in children at risk of malnutrition. In fact, it may even increase the risk of diarrhea lasting more than a few days.
  • Fall prevention. Taking folic acid and vitamin B12 by mouth does not seem to prevent falls in elderly people who take vitamin D at the same time.
  • Male infertility. Taking folic acid by mouth alone or with other ingredients does not seem to improve male fertility.
  • Unborn or premature babies die. Taking folic acid by mouth during pregnancy does not seem to reduce the risk of death before or after birth. But it does help prevent other health problems in babies.
  • Leukemia (leukemia). Taking folic acid by mouth during pregnancy does not reduce the risk of this type of cancer in children.
  • Weak bones (osteoporosis). In elderly people with osteoporosis, oral folic acid and vitamin B12 and/or vitamin B6 does not seem to prevent fractures.
  • The physical performance of the elderly. Taking folic acid and vitamin B12 by mouth does not seem to help older people walk better or have stronger hands.
  • High blood pressure during pregnancy. High-dose folic acid supplements do not seem to lower blood pressure during pregnancy, nor do they reduce the risk of pre-eclampsia.
  • Respiratory tract infection. Oral folic acid does not seem to prevent lung infections in children at risk of malnutrition.
  • Non-cancerous growths in the large intestine and rectum (colorectal adenoma). Taking folic acid supplements does not prevent the growth of the large intestine or rectum.
  • A genetic disorder characterized by learning disabilities (fragile X syndrome). Taking folic acid by mouth does not improve the symptoms of Fragile X syndrome.
  • Premature delivery. Taking folic acid by mouth during pregnancy does not reduce the risk of premature babies. But it does help prevent other health problems in babies.

side effect

Oral: For most people, taking no more than 1 mg of folic acid per day may be safe. Doses exceeding 1 mg per day may be unsafe. These doses may cause stomach upset, nausea, diarrhea, irritability, confusion, behavior changes, skin reactions, seizures, and other side effects.

Another form of folic acid, L-5-methyltetrahydrofolate (L-5-MTHF), can also be found in supplements. This type of folic acid may be safe for most people, taking about 400 micrograms per day.

Some people worry that taking too much folic acid for a long time may cause serious side effects. Some studies have shown that taking 0.8-1.2 mg of folic acid daily may increase the risk of cancer or heart attack in people with heart disease.

Special precautions and warnings

Pregnancy and breastfeeding : It is recommended to take 300-400 micrograms of folic acid every day during pregnancy to prevent certain birth defects. The maximum recommended amount of folic acid during pregnancy or breastfeeding is 800 micrograms per day for people under 18 and 1,000 micrograms per day for people over 18 years of age. Do not use more unless directed by a healthcare professional.

Another form of folic acid, L-5-methyltetrahydrofolate (L-5-MTHF), can also be found in supplements. This type of folic acid may be safe to take 400 micrograms per day during pregnancy or breastfeeding.

Children : It may be safe for children to take the recommended amount of folic acid suitable for their age. However, children should avoid taking folic acid doses higher than the daily upper limit. These limits are 300 micrograms for 1-3 years old, 400 micrograms for 4-8 years old, 600 mg for 9-13 years old, and 800 micrograms for 14-18 years old.

Another form of folic acid, L-5-methyltetrahydrofolate (L-5-MTHF), can also be found in supplements. This type of folic acid may be safe for children.

Procedure to enlarge narrowed arteries (angioplasty) : The use of folic acid, vitamin B6 and vitamin B12 may worsen narrowed arteries. People recovering from this process should not use folic acid.

Cancer : Early research suggests that taking 0.8-1 mg of folic acid daily may increase the risk of cancer. Before learning more, people with a history of cancer should avoid taking high doses of folic acid.

Epilepsy : Taking folic acid supplements, especially high-dose folic acid supplements, may make people with epilepsy have more severe seizures.

interactive

Moderate interaction

Be cautious with this combination

  • Phosphenytoin (Cerebyx) interacts with folic acid

    Fosphenytoin (Cerebyx) is used for seizures. The body breaks down phosphphenytoin (Cerebyx) to get rid of it. Folic acid can increase the speed at which the body breaks down phosphphenytoin (Cerebyx). Taking folic acid with fosphenytoin (Cerebyx) may decrease the effectiveness of fosphenytoin (Cerebyx) to prevent seizures.

  • Methotrexate (MTX, Rheumatrex) interacts with folic acid

    The role of methotrexate (MTX, Rheumatrex) is to reduce the effect of folic acid on human cells. Taking folic acid pills and methotrexate may decrease the effectiveness of methotrexate (MTX, Rheumatrex).

  • Phenobarbital (Luminal) interacts with folic acid

    Phenobarbital (Luminal) is used for seizures. Taking folic acid will reduce the effect of phenobarbital (Luminal) in preventing seizures.

  • Phenytoin (Dilantin) interacts with folic acid

    The body breaks down phenytoin (Dilantin) to get rid of it. Folic acid may increase the speed at which the body breaks down phenytoin (Dilantin). Taking folic acid and phenytoin (Dilantin) may decrease the effectiveness of phenytoin (Dilantin) and increase the likelihood of seizures.

  • Primidone (Mysoline) interacts with folic acid

    Primidone (Mysoline) is used for seizures. Folic acid may cause seizures in some people. Taking folic acid and primidone (Mysoline) may decrease the effectiveness of primidone in preventing seizures.

  • Pyrimethamine (Daraprim) interacts with folic acid

    Pyrimethamine (Daraprim) is used to treat parasitic infections. Folic acid may reduce the effectiveness of pyrimethamine (Daraprim) in treating parasitic infections.

Dosing

Folic acid is an important nutrient. The amount that should be consumed every day is called the Recommended Dietary Allowance (RDA). The RDA of folic acid is provided in the form of dietary folate equivalent or DFE. This is because the body can absorb folic acid in supplements better than folic acid in food. 1 microgram of DFE is the same as 1 microgram of folic acid in food. But 1 microgram of DFE is the same as 0.6 microgram of folic acid supplement.

The RDA for adults is 400 micrograms of DFE per day. During pregnancy, the RDA is 600 micrograms of DFE per day. When breastfeeding, the RDA is 500 micrograms of DFE per day. In children, RDA depends on age. Talk to a healthcare provider to find out the best dose for a specific situation.

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