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Folic Acid (Folate = Vitamin B9)



Folate (B9), along with vitamin B12 (cobalamin), is vital in the formation of red blood cells,  in the production and methylation of DNA and RNA, and cell division, especially in cells with high turnover rates.  In the endurance athlete, red blood cells have high turnover due to the stresses of training and adequate folate aids in rapid replenishment.  Surveys have shown folate has a tendency to be under-consumed by some athletes, especially in females. Folate has been shown to increase tissue regeneration and repair.  Adequate levels encourage efficient and ample formation of healthy red blood cells, a necessity for the health and performance of any athlete. Folate is critical for proper brain functioning and also helps iron to function properly in the body.  As mentioned with regards to B6, folate is important in the maintenance of healthy homocysteine levels and with the help of B12, converts homocysteine to the amino acid methionine. This is important as intensity of exercise has been directly correlated to elevated plasma homocysteine levels and inflammation in the body. This finding could be inferred to show possible increased health risk from certain intense exercise.  Research has demonstrated folate's ability to reduce these levels and that when exercise intensity increases, the consumption of additional folate doesn't raise plasma folate levels but further reduces homocysteine levels. This could potentially diminish or neutralize the cardiovascular risk posed by exercise-induced elevated homocysteine.


Folic Acid vs. Folate:


To clear up some common confusion, folic acid is the biologically inactive, synthetic form of B9 found in many supplements and fortified foods.  Folic acid must be broken down adequately to the active forms of folate (dihydrofolate, 5-methyltetrahydrofolate (5-MTHF), and tetrahydrofolic acid) to be useful.  Recent research in epigenetics has revealed that a significant percentage of the population have genetic challenges to the process by which certain vitamins are broken down or methylated to their most biologically active forms.  Estimates suggest that from 20-40% of the general population, have genetic issues that present difficulties with methylation and that this percentage is on the rise. Most are unaware they have the issue. Thus individuals with methylation issues will often have great difficulty turning folic acid or cyanocobalamin (synthetic inactive B12)  into safe biologically active forms of the vitamins and deficiencies could result even though supplementation is taking place. The unused inactive forms of the vitamins, like unmetabolized folic acid (UFA) can also result in individuals without genetic methylation issues by simply consuming more folic acid than the liver is able to convert.  The excess inactive forms, such as UFA could also put further pressure on detoxification pathways to rid the body of them. There are genetic tests that can determine the type and extent of inherited methylation issues, if any, that one may have. Until that testing becomes commonplace RunTheLabs will recommend only natural, active or pre-methylated supplemental forms of folate and B12.  For B12, it's methylcobalamin. For folate, the methylated forms which have good absorption and are bioactive are L-5-methyltetrahydrofolate (L-5-MTHF), 6 (S)-Methyltetrahydrofolate (6(S)-L-MTHF), L-Methylfolate Calcium, Metfolin, Levomefolic Acid, and Quatrefolic. For more information on this, skip ahead to the Methylation topic.


The RDA for folic acid is 300 mcg for 9-13 year olds.  This goes to 400 mcg for 14 years and older. 600 mcg is recommended during pregnancy and 500 mcg while breastfeeding.  The U.S. Institute of Medicine has set a tolerable upper limit (UL) for folic acid at 1000 mcg per day for adults and 300-800 mcg per day for children.  Most labs don't delineate between active and inactive forms of folate and so it is difficult to determine how much of the folate measured is active and how much is potentially toxic UFA.   Folate deficiencies can lead to megaloblastic anemia, certain cancers, and birth defects such as neural tube defects. Megaloblastic or macrocytic anemia results from drops in DNA synthesis in developing red blood cells  from a lack of adequate folate or B12. This prevents red blood cells (RBCs) from developing normally, stops cell division and the cells grow abnormally large to form "megaloblasts" aka "macrocytes" in a process known as macrocytosis.  These impaired RBCs are inefficient transporters of oxygen and the result is an anemia often characterized by painful tingling in the hands and feet, diarrhea, fatigue, incoordination, diminished appetite and weight loss. Symptoms can be exaggerated by training or competing at altitude due to lower available oxygen concentration.  This anemia can significantly interrupt athletic training and performance but is not nearly as common as iron deficiency anemia.


Folate can be supplemented with a complete B vitamin complex to benefit from all of the synergism in and amongst this group of vitamins.  A quality B complex for our purposes will use only the methylated or at least natural forms of folate (methyl folate), Vitamin B6 (P5P) and B12 (methylcobolamin).  B-Complex with Metfolin and Intrinsic Factor by Douglas Labs is our product of choice as it ticks all of those boxes, contains intrinsic factor to help B12 absorption for those lacking the protein,  and contains the only form of folate known to cross the blood-brain barrier. We recommend about 800 mcg of folate, preferably methlylated, per day for the training athlete, this is achieved with 2 capsules of the Douglas Labs B-Complex mentioned above. 


Foods rich in natural folate:

Most beans, lentils, spinach, turnip greens, asparagus, romain lettuce, broccoli, pomegranate, avocado, many tropical fruits, and oranges.


Drug interactions:


Methotrexate, a chemotherapeutic agent used to treat cancer and rheumatoid arthritis, significantly reduces folate in the body.  As this is widely accepted, individuals on this medicine are often given high doses of folate in the form of folinic acid. Because of folate's roll in rapid cell division, those treating for cancer should never consider folic acid or folate supplementation without the assistance of their oncologist as it may interfere with the effectiveness of the drug.  Many nonsteroidal anti-inflammatory drugs (NSAIDs), antacids, H2 blockers, and proton pump inhibitors also reduce folate levels. Birth control medications, anticonvulsants and bile acid sequestering cholesterol medications can do this as well.

Folic acid supplementation can interfere with the effectiveness of the antibiotic tetracycline and shouldn't be taken at the same time.


How we test:


Serum Folate = level of all forms of folate in the serum                  

RunTheLabs Optimum Range:  > 10 ng/mL

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