Folate and folic acid are water-soluble vitamins that have several health benefits, especially during early pregnancy. Good dietary intakes of folate and folic acid may also help to protect against erectile difficulties, stroke and heart attack, and reduce the risk of developing dementia – including Alzheimer’s disease.
Folates, folic acid and methylfolate
Sometimes referred to as vitamin B9, the types of folate found in foods are classed as polyglutamates as they contain several molecules of glutamic acid. These forms of folate must be digested down into simpler molecules containing just one molecule of glutamic acid (monoglutamates) before they can be absorbed.
Folic acid is a synthetic form of folate and is already in the monoglutamate form. Folic acid is therefore absorbed and used more quickly and efficiently than dietary folates. Because of this better bioavailability, folic acid is the preferred type of folate added to supplements and fortified foods such as breakfast cereals.
There is a catch however.
In order for cells to use the absorbed form of folates or folic acid, they must be converted into an active substance called methylfolate. Some people inherit genes which mean they do not efficiently convert dietary folate or folic acid to this methylated form, however. One study estimated that 60% of the population are intermediate metabolizers of folate and folic acid, and that up to a quarter are poor metabolisers of folate and folic acid. This can lead to cells being deficient in folate even though there is plenty in the diet or in the supplements you are taking.
Some nutritionists therefore recommend looking for supplements supplying methyl folate (metafolin) as this more bioavailable form can be absorbed and used by anyone.
Why you need folate and folic acid
Folates and folic acid are involved in the synthesis and metabolism of proteins, sugar and nucleic acids. They are especially important for rapidly dividing cells such as those in the bone marrow. When folic acid is in short supply, dividing cells become larger than usual and, when red blood cells are affected, a form of anaemia known as macrocytic anaemia results.
Folate is essential during the first few weeks of fetal development in the womb. Deficiency can trigger a type of developmental abnormality known as a neural tube defect (eg spina bifida) which can arise between the 24th and 28th day after conception. This is sometimes before a new mum knows she is pregnant, which is why folic acid supplements are recommended before you try to conceive.
Folate is also needed to process a harmful amino acid, called homocysteine, which can damage artery linings if it builds up in the circulation, to trigger hardening and furring up of the arteries (atherosclerosis). Two of the three enzymes that help to convert homocysteine to other safe amino acids depend on folate for their activity.
Within the EU, the European Food Safety Authority has authorised health claims that folate contributes to:
- Maternal tissue growth during pregnancy
- Normal amino acid synthesis
- Normal blood formation
- Normal homocysteine metabolism
- Normal psychological function
- Normal function of the immune system
- The reduction of tiredness and fatigue
- The process of cell division
- Protecting against the development of neural tube defects in early pregnancy.
Food sources of folate
The name folate comes from the Latin word folium, meaning leaf, as this is where the vitamin was first identified. Food sources of folate include:
- green leaves such as spinach, broccoli, Brussel sprouts, parsley
- wholegrains
- beans, especially soy products
- offal, especially liver
- citrus fruit
- nuts
- dairy products
- eggs
- yeast extract
It’s difficult to obtain optimum amounts of folate from diet alone, however, as foods typically retain less than a third of their folate content after processing and cooking.
Folate is destroyed by prolonged contact with light and air but can be protected by antioxidant vitamin C. Up to 90% of folate content of grain is lost during milling, 10% of folate in vegetables is lost by steaming, 20% by pressure cooking and up to 50% by boiling.
Symptoms of folate deficiency
While a little folate is stored in the liver, dietary lack rapidly leads to insufficiency. Lack of folate is recognised as the most widespread vitamin deficiency in developed countries. Some anti-epilepsy drugs also lower folate levels.
Symptoms that may be due to lack of folate
- tiredness
- weakness
- irritability
- forgetfulness
- insomnia
Symptoms that may be due to major folate deficiency
- anaemia
- muscular cramps
- confusion
- red, sore tongue
- cracking at the corners of the mouth
- depression
- dementia
Folate and pregnancy
A large analysis of data from 5 trials, involving almost 6,700 women, showed a protective effect of daily folic acid supplements at a dose of 400 micrograms (0.4 mg) or higher (whether alone or in combination with other vitamins and minerals) in preventing neural tube defects, reducing the risk by 69%.
Supplements containing methylfolate and vitamin B12 may decrease rates of anaemia in pregnancy better than prenatal supplements supplying folic acid.
Folate and twin pregnancy
If you conceive twins, there is some evidence that supplements may increase the chance of both fetuses successfully developing as the need for folate is at least twice as high as for a singleton pregnancy during early stages of development. This is controversial, but I like to think that I am blessed with my own twins because I took a prenatal supplement providing folic acid before and after I became pregnant.
Folic acid and stroke
The results of 17 trials, involving 86,393 people, found that the risk of stroke was reduced the most in people taking supplements that included folic acid, or folic acid plus vitamin B6, or folic acid plus vitamin B6 and vitamin B12,compared with palcebo. The protective effect is partly due to the way in which folic acid reduces the progression of hardening and furring up of the carotid arteries which supply blood to the brain.
Folic acid and heart attack
Taking a supplement that includes 400 mcg folic acid, plus 2 mg vitamin B6, and 10 mcg vitamin B12 can significantly improve risk factors for coronary heart disease such as improving cholesterol balance, lowering homocysteine levels and reducing blood pressure. Results from 23 trials involving 57,900 people concluded that taking these B vitamins was associated with a 2% reduced risk of heart attack, a 4% lower risk of cardiac death and a 6% reduced risk of stroke although these effects did not reach statistical significance and more research is needed.
Folic acid and erectile dysfunction
By hastening the breakdown of homocysteine, folic acid helps to protect against hardening and furring up of the arteries (atherosclerosis) which is a leading cause of erectile difficulties in older men, and in males with diabetes.
An Italian study measured folate and homocysteine levels in 75 men with erectily dysfunction, then prescribed Viagra (sildenafil citrate) to all participants. After 2 months, the 18 men who did not respond to Viagra were all in the group that had a high homocysteine level and a low blood folic acid level. These were prescribed high dose folic acid and vitamin B6 (in addition to their Viagra treatment for another 6 weeks. Of the 18 non-responders, 16 (88.9%) reported a significant improvement in erections after taking the combination vitamin treatment.
If you are a male with erection difficulties, taking a supplement that includes folic acid and vitamin B6 may help if you have high homocysteine levels. It may also improve the effectiveness of Viagra treatment.
Folic acid and dementia
Low levels of folate (folic acid) are an accepted risk factor for developing dementia. Older people who take a high-dose B vitamin supplement that supplies 800 mcg folic acid plus 20 mg vitamin B6 and 500 mcg vitamin B12 were found to have less cognitive decline due to reduced shrinkage of whole brain volume over a 2 year follow-up period. Shrinking in one part of the brain, which is especially associated with Alzheimer’s disease (the medial temporal lobe grey matter) was reduced by a factor of seven in those taking the folic acid, B6 and B12 supplements. The benefits were most evident in people with a high blood homocysteine level. B vitamins may be most effective when combined with a good intake of omega-3 fish oils.
Folic acid and depression
Lack of folate can increase the risk of low mood and clinical depression. The results from 11 studies, in which over 15,000 people took part, found that low folate intakes was linked with a 55% increased risk of depressive illness.
Folic acid and diabetes
Taking metformin to improve insulin resistance in type 2 diabetes increases homocysteine levels. This effect can be counteracted with folic acid supplements and may improve glucose control although more research is needed to confirm this.
How much folate or folic acid do you need?
The EU RDA for is 200 mcg while the US DV is 400mcg.
Requirements for folate increase during pregnancy and lactation.
Women planning a pregnancy are advised to take daily supplements containing 400 mcg folic acid from before the time of conception until at least the 12th week of pregnancy. Some nutritionists recommend looking for supplements supplying methylfolate rather than folic acid.
The European Food Safety Authority has determined a tolerable upper intake level for long-term use from folate or folic acid supplements as 1mg (1000mcg). For short-term use during early pregnancy, higher doses of 4mg per day may be advised under medical supervision if you have a personal or family history of conceiving a child with a neural tube defect.
Typical folate intake
The average western diet supplies 260mcg folate per day.
Safety of folate and folic acid
Folic acid is generally considered safe, but long-term use of high doses can mask vitamin B12 deficiency as it prevents the occurrence of red blood cell changes that usually allow lack of vitamin B12 to be detected. These two supplements are usually taken together for long-term use.
Some anti-epilepsy drugs affect folate metabolism. People taking drugs to treat epilepsy should tell their doctor if they take folic acid supplements so blood levels of their medication can be monitored where appropriate.
For women on anti-epileptic drugs, it is vitally important to obtain advice about taking extra folic acid supplements before trying to conceive a baby.
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