Vitamin B9 in Dark Green Vegetables: Deficiency Disorders, Bio-Availability, and Fortification Issues

Folic acid is a B complex water-soluble vitamin that is essential to humans, and its deficiency can cause problems including neural tube defects as well as heart-related diseases. An important feature of such vitamins is that they are generally not synthesized by mammalian cells and therefore must be supplied in sufficient amounts in the diet. Folate is a generic term for compounds, possessing vitamin activity similar to that of pteroylglutamic acid, and is the form of the vitamin, which is naturally present in foods. The main dietary sources of folic acid are dark green and leafy vegetables such as spinach, asparagus, romaine lettuce, broccoli, bok choy, turnip green, beet, dried or fresh beans, and peas. The amount of folate that is absorbed and utilized physiologically varies among different food sources and different chemical forms of the vitamin. About 85% of folic acid is estimated to be bioavailable; however, the bioavailability of food folate is estimated at about 50% of folic acid. Several national health authorities have introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bio-efficacy. Presently, many countries affected by diseases associated with a lack of folic acid have made it mandatory to supplement foods with the vitamin. Considering the need, several analytical procedures were standardized to determine the presence of folic acid in different food matrices. The reported methods are simple, selective, robust, and reproducible and can be used in routine analyses.