Bioavailability of folate from processed spinach in humans - Effect of food matrix and interaction with carotenoids

The effect of the food matrix and dietary fibre on the bioavailability of f olate is not known. In a controlled, 3-week dietary intervention study, 28 men and 42 women were divided into six groups to receive either a control d iet (n = 10), or the control diet plus 20 g/MJ per day (n = 12 per group) o f whole-leaf spinach, minced spinach, liquefied spinach, or liquefied spina ch to which dietary fibre (10 g/kg wet weight) was added. The sixth group r eceived the control diet plus a synthetic carotenoid supplement with simila r amounts of P-carotene and lutein as found in spinach. A significantly hig her plasma folate response was found for the pooled spinach groups than for the control group. Among the spinach groups no significant differences wer e detected. However, the plasma folate response of the pooled minced and li quefied spinach groups was greater than that of the whole-leaf spinach grou p (p = 0.03). Re-addition of dietary fibre to the liquefied spinach to comp ensate for the fibre broken down during liquefaction did not reduce the pla sma folate response. The consumption of the carotenoid supplement did not h ave an effect on plasma folate concentrations compared with the control gro up. The food matrix in which the folate is entrapped plays a role in folate bioavailability. Copyright (C) 2000 S. Karger AG, Basel.