Citrus Pectin and Oligofructose Improve Folate Status and Lower Serum Total Homocysteine in Rats

Abstract

Low folate status leads to increased total homocysteine (tHcy) concentration, and this has been associated with an increased risk of several diseases. Many colonic bacteria are capable of synthesizing folate, and certain dietary fibers may enhance this effect. We assessed the ability of non-fermentable (cellulose) and fermentable (citrus pectin and oligofructose) fibers to improve folate status and lower tHcy in rats. Weanling Sprague-Dawley rats were fed a folate-deficient diet with 5% cellulose for four weeks. Rats were then randomly assigned to one of five folate-adequate (400 mug/kg diet) test diets for 24 days. Diets were as follows: Basal; Basal + Sulfa Drug (succinylsulfathiazole); Cellulose; Citrus Pectin; and Oligofructose. High-fiber diets were formulated by diluting the basal diet such that the final diets contained 10% of the added fiber. Twenty-one days later, 3H-r-aminobenzoic acid was injected into the cecum, and rats were terminated three days later. Rats receiving the Citrus Pectin diet had significantly higher plasma (p = 0.011), erythrocyte (p = 0.035), and colonic tissue folate concentrations (p = 0.013) and lower tHcy (p = 0.003) than rats given the Cellulose diet. Rats receiving the Oligofructose had significantly higher plasma folate (p < 0.001) and lower tHcy (p = 0.032) concentrations than rats receiving the Cellulose diet. 3H-folate was detected in the livers of all rats except those receiving Sulfa Drug. Our study indicates that Citrus Pectin and Oligofructose, but not Cellulose, can significantly increase indices of folate status in rats and lower tHcy. It also confirms the ability of the large bowel to absorb folate.