Plasma folate concentrations after a single dose ingestion of whole and skimmed folic acid fortified milks in healthy subjects.
Since mandatory folic acid fortification of grains and cereals was introduced in order to prevent neural tube defects, the number of products that are being fortified with folic acid is growing, especially milk and dairy products. However, the effectiveness of this action remains controversial. To investigate the efficiency of skimmed milk as a vehicle for folic acid fortification by the determination of the acute absorption from low-fat fortified milk compared to fortified and unfortified whole milk in healthy subjects. A single-dose bioavailability study was performed using three commercially available milks (whole and skimmed milk fortified with folic acid and unfortified whole milk). Healthy volunteers (3 women, 2 men) were administered a single dose of 430 ml of each milk, at 1-week intervals between test days. Plasma total folate concentrations, at baseline and hourly from 1.5 up to 6.5 h after ingestion, were measured. Plasma folate concentration was significantly increased, when compared to baseline values, 1.5 h after ingestion of skimmed fortified milk, and 2.5 h after whole fortified milk, and remained significantly higher than baseline values for up to 6.5 h after both treatments. The highest plasma folate concentration (20.9 ± 3.1 nmol/l) was obtained 6.5 h postprandial in response to skimmed fortified milk. The acute absorption of folic acid, calculated on the basis of area under the plasma folate concentration curve, was significantly higher from skimmed fortified milk compared to fortified and unfortified whole milk. The absorption of folic acid from fortified skimmed milk is faster than the absorption of folic acid from fortified whole milk, and it renders significantly higher plasma folate concentration when compared to whole milk. These findings indicate that skimmed milk could be considered an efficient food matrix for folic acid fortification.