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Folate intake

FOLATE INTAKE FROM FOOD
The recommended intake of folate for adults in Finland are as follows (these are similar in other European countries and in the US):

  • Men: 300 mcg per day
  • Women aged 18-30: 400 mcg per day
  • Women aged 31+: 300 mcg per day
  • Pregnant and breastfeeding women: 500 mcg per day

The average folate intake for adult Finnish men (aged 25–64) is 270 mcg per day and for adult women (aged 25–64) it is 234 mcg per day. Folate is one of the primary nutritional factors where the average intake on a population level does not meet the guidelines. Taking folate as a dietary supplement may, therefore, be particularly useful for many individuals. 13.1 % of Finnish men and 21.7 % of women take a dietary supplement containing folic acid (or folate). The average intake of folic acid from supplements is 530 mcg per day.
Increasing the folate level in the blood is more effective when combined with vitamin C. This is known to improve the bioavailability of folate in the body. Conversely, cooking green, folate-rich vegetables or storing them at a room temperature destroys a significant portion of the folate.


Folate or folic acid is frequently used alongside methotrexate to protect the body from the drug’s side effects. According to a 2001 study conducted on Finnish men, the individuals with the highest folate intake from food were 55 % less likely to have an acute cardiac event (such as coronary thrombosis) compared to the individuals with the lowest folate intake from food. A very comprehensive meta-analysis indicates that the individuals who took 800 mcg folic acid as a dietary supplement saw their homocysteine levels decrease by approximately 25 %. To lower homocysteine levels, the American Heart Association recommends the following cocktail: 400 mcg folic acid or folate, 2 mg vitamin B6 and 6 mcg vitamin B12.


A common dose to treat established deficiency is 1 mg per day. In some severe malabsorption cases, the dose may be up to 5–15 mg per day. This requires medical follow-up and regular testing.


The upper limit of safe folic acid (or folate) intake for healthy individuals in Finland has been established at 1 mg (1,000 mcg) per day.
Folate from food has not been found to cause side effects. Excessive folic acid intake together with undiagnosed vitamin B12 deficiency may increase the risk of neurological damage. The use of bioactive folate (5-MTHF), on the other hand, has not been linked to side effects.


MEASURING FOLATE LEVELS IN LABORATORY:
Folate levels can be measured either from blood serum, red blood cells, or whole blood. Of these, the red blood cell test paints the most accurate picture of the long-term folate intake from food as well as the levels in the body. Changes to the folate balance first become apparent in the serum folate levels, whereas fE-Folate (folate in erythrocytes) is not as sensitive to dietary changes etc. when compared to fS-Folate. Due to this, fE-Folate is considered to be a more reliable indicator of folate deficiency compared to fS-folate.


The transportation of folate into a cell requires the presence of vitamin B12. When vitamin B12 deficiency is present, fE-folate may be reduced, even if the serum level is normal or elevated. When investigating macrocytic anemia, it is recommended to also determine the level of active vitamin B12 (S-B12-TC2). Folate deficiency usually occurs together with increased homocysteine levels.


The Finnish reference range (fE-folate):

  • 208–972 nmol/L

The fE-folate value is often above the reference range in individuals who take folate supplements. The continued use of the dietary supplement is no longer sensible or useful in these cases. The optimal folate level is in the top third of the reference range.