Is it really free of side effects?
In numerous texts and informative articles we read that folic acid (vitamin B9) is a safe, water-soluble molecule that does not produce side effects. Of course, adequate supplementation of this very important vitamin, specific for the needs of the individual, can only bring important benefits to the body.
However, the skill and cunning of some advertising propaganda and certain internet sites seem to be making fun of potential customers, exploiting their credulity and ingenuity to encourage them to take megadoses of folic acid in order to prevent possible (and terrible) risks from deficiency ", on which particular (and excessive) emphasis is placed. It is clear that, by tracing the hand on the possible effects produced by a lack of folic acid, the potential customer is scared by convincing him that it is better to exceed with the doses, in the mistaken belief that "so much, it does not hurt".
Please note
What many advertising channels do not specify is that folic acid can bring unpleasant side effects even when taken in excess.
Recommended doses and overdose
Folic acid is a safe molecule and does not produce any side effects when taken within the recommended doses for one's health and age.
As an indication, the recommended daily intake of folates is:
- 200-300 mcg (micrograms or µg) in the adult
- 400 mcg in pregnancy
- 350 mcg during lactation
For the treatment of certain cardiovascular diseases, some doctors recommend taking folic acid in higher quantities, in the order of 400-1000 mcg per day.
Some pregnant women particularly at risk of folic acid deficiency even need 5 mg (5000 mcg) of folic acid a day (to be taken in the form of supplements). Despite this, pregnant women are advised to scrupulously respect the dosages of folic acid prescribed by the doctor: some side effects have been reported in the newborn following an exaggerated integration of vitamin B9 by the mother during pregnancy. In these children a higher incidence of asthma and wheezing was already recorded during the neonatal and infant age.
Side effects of overdose
Although the risk of toxicity due to excess folic acid is relatively low, it is still advisable to consider what side effects an exaggerated surplus of this vitamin could generate.
Except for some pregnant women particularly at risk of folic acid deficiency, in healthy adults, an intake of vitamin B9 higher than 400-1000 mcg / day could cause side effects from overdose.
The table shows the most common overdose risks and possible side effects (albeit quite rare).
Frequent side effects from folic acid overdose (dosages> 400 mcg / day but less than 1000 mcg) | Rare side effects of folic acid overdose (dosages> 1000 mcg / day) |
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Very high doses of folic acid can generate serious side effects in the central nervous system.
Epileptic patients who take high doses of folic acid risk accentuating the symptoms of seizures.
We must not forget, moreover, that an excess of folic acid could hide the symptoms of blood diseases such as pernicious anemia, a disease caused by the protracted and untreated vitamin B12 deficiency. This form of anemia, whose symptoms are precisely hidden by an overdose of folic acid, could cause serious problems of a neurological nature to the victim, such as the appearance of paresthesia, loss of sensitivity and, in the most serious cases, total paralysis.
Side effects from interactions
Some patients must pay particular attention to taking folic acid supplements, since vitamin B9 could cause unpleasant side effects in the body following interaction with certain drugs:
- Folic acid can cause a more or less sensitive reduction in blood pressure. Therefore, to avoid similar side effects, patients who take drugs or natural substances that lower blood pressure must scrupulously respect the dosages of folic acid prescribed by the doctor.
- Folic acid should be used with extreme caution in combination with aspirin: some studies performed in humans suggest that, under similar circumstances, vitamin B9 is able to reverse the beneficial effects of aspirin on C-reactive protein ( known inflammatory marker). Let us briefly recall that aspirin can be used in the treatment of diseases such as acute pericarditis or other heart diseases to reduce blood levels of the C-reactive protein (exaggerated by the disease); in such circumstances, the concomitant use of folic acid and aspirin cancels or reverses the effect of the drug.
- An intravenous loading dose of folic acid, vitamin B6 and vitamin B12, followed by oral intake of the same cocktail of substances, administered daily after a coronary stent operation (a small tube inserted into an artery to prevent obturation) could increase the risk of restenosis (reformation of the atheromatous plaque that occurs in the first months after the artery dilation intervention). To minimize the risk of restenosis in these patients, it is necessary to avoid the administration of this vitamin combination.
- It seems that the prophylactic and long-term supplementation of folic acid and iron can somehow increase the risk of death in patients living in areas with a high risk of malaria. Let us briefly recall that folic acid can be used in the treatment of malaria anemia together with iron because the synergistic action of the two substances seems to significantly improve the anemic picture compared to iron-only monotherapy. However, it seems that the administration of drugs in the long term, for prophylactic purposes, is not recommended due to the increased risk of death.
- Folic acid can reduce blood glucose levels: for this reason, diabetic patients taking specific drugs to control their blood sugar must pay particular attention to taking folic acid to avoid unpleasant side effects.
- Many of the folic acid side effects reported in the article are taken up on the Mayo clinic website: //www.mayoclinic.com/health/folate/NS_patient-folate/DSECTION=safety
