Folic acid side effects

Folic Acid: Should A Woman Take It Or Not? | Side Effects

Folic acid is a B vitamin that plays a crucial role in the development of the neural tube, which forms the baby’s brain and spinal cord.

It is often recommended that women who are trying to conceive and those pregnant should take folic acid.

According to studies taking folic acid before and during pregnancy can significantly reduce the risk of neural tube defects in the baby.


But is it possible that this necessary vitamin also deliver negative results when it is excess? YES!

We will find out what science says about excess of this vitamin tablets women often swallow.

Why Do Women Take Folic Acid?

Really, there are other things about folic acid that people who take it are not aware of.

First, not many are aware that women can get enough of this vitamin B9 from the foods they eat.

It comes in form of folate.

Take note that when it comes as supplement it is folic acid and when you get it naturally from plants, it is folate.

Foods that are naturally high in folate include leafy vegetables, okra, asparagus, certain fruits, beans, yeast, mushrooms, animal liver and kidney, orange juice, and tomato juice.

In whatever form it comes – folate or folic acid – this vitamin B9 is important for cell and DNA formation in your body (1).

Physicians recommend folic acid, as supplement when there is a folate deficiency (low blood levels of folate).


Sadly low blood levels of folate have been linked to health issues  – risk of birth defects, heart disease, stroke, and certain cancers(2) (3) (4).

Side Effect Of Taking Folic Acid

It is important that before you supplement folic, you should know a few things.

This knowledge will help you make the right choice.

First, high blood levels of folate are not a concern for most healthy adults.

However, consuming excessive amounts of folic acid from supplements can be harmful.

That said, in the US, since 1998, folic acid shows up in cold cereals, flour, breads, pasta, bakery items, cookies, and crackers, as required by federal law.

When it comes to absorption of folate and folic acid, your body doesn’t absorb folate easily. But it absorbs folic acid easily.

From findings, about 85% of folic acid from fortified foods or supplements is absorbed, while only 50% of natural folate from foods is used by your body (5).

This 50% absorption was for a reason and the maker of humans knows well. You will find out soon.

You see, when you take folic acid supplement, it heads to your bloodstream. From there, it hits your liver and it brakes it down into smaller compounds. But the liver has a limit to how much of this compounds it must process (6).

So what happens to the left over that your liver  could not process?

Excess Vitamin B9 In The Blood

That is where the is issue with supplementing folate lies.

Unfortunately, vitamin B9 comes in some other foods you eat, as mentioned earlier. So, that loads your blood with this vitamin.

Furthermore, the folic acid that the liver cannot process stays in your blood.


As a result, consuming too much folic acid from fortified foods and supplements can cause unmetabolised folic acid to accumulate in your blood.

However, this does not happen when you take folate from foods (7).

Unfortunately, when there is accumulation of this vitamin in the blood, it could causes several health issues (8), (9), (10), (11).

Recommended Amount

Basically, the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine have developed dietary folate equivalents (DFEs) to set clearer folate intake recommendations (12).

They recommend that you stick with 1 mcg DFEs which is:

  • 1 mcg of folate from foods
  • 0.6 mcg of folic acid from fortified foods or dietary supplements consumed with foods
  • 0.5 mcg of folic acid from dietary supplements taken on an empty stomach

The National Institutes of Health (NIH) recommends that adults over the age of 19 should not exceed 1,000 mcg per day.

For children 300–800 mcg is recommended and this is age-dependent. (13).

Therefore, if you abuse this supplement, strange things could happen.

1.     Could Dump Vitamin B12 Deficiency On You Suddenly

A study says when you have excess of folic acid in your blood, it would mimic vitamin B12 and make a deficiency of the vitamin B12 impossible to detect.

When this deficiency goes undetected for long, it will damage your nerve. This damage is often irreversible (14).

When there is this excess, it could cause weakness, fatigue, difficulty concentrating, and shortness of breath (15), (16).

2.     Excess Folic Acid Could Slow Brain Development In Children

There are chances that a woman may not be getting enough folate from food. This is often so, when  she does not know the right foods to take for folate.

As a result, she may be asked to take supplement for folate.

This can lead to excess of folic acid in the blood. This often increases insulin resistance, resulting in slow brain development in children.

According to a study,  4 and 5-year-olds whose mothers supplemented with over 1,000 mcg of folic acid per day while pregnant scored lower on brain development tests than the children of women who took 400–999 mcg per day (17) .

This insulin resistance could also be carried on by the child after birth and it will manifest in their early years (18).

3.    Could Speed Up Age-related Mental Decline

You see, when women become forgetful as they advance in age, the high intake of folic acid could be the reason.

Mummy brain could be a function of this.

A study found that when there is a masking of vitamin B12 deficiency, with high folate presence, a woman could experience loss of brain function (19).

Also, another study of people that are over 60 years found that high levels of folate in the blood could cause mental decline in those with low levels of vitamin B12 (20)

4.    Excess Folic Acid Could Increase Likelihood Of Cancer Recurrence

When it comes to folic acid and cancer risk, it is often two-sided.

On one hand, when healthy cells are exposed to adequate level of this supplement, it protests them from becoming cancerous.


On the other hand, when cancerous cells are exposed to high levels of this vitamin B9 supplement, it could help the cancer cells grow or spread (21), (22).

While studies show this, there are also other studies that have not found any link with cancer (23), (24).

However, we know that whenever there is an excess of something in the blood, trouble is brewing.

This is one reason you need to focus on foods that offer folate in its natural form.

This will ensure that you do not have excess of it in your blood and that could cause trouble for you and your unborn baby.

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