Bioavailability of Vitamin E in Rats Fed Graded Levels of Pectin

Abstract

Dietary pectin at levels of 0, 3, 6 and 8% was fed ad libitum to rats for 8 wk to evaluate whether the bioavailability of vitamin E fed at 0.001% of the diet was affected by pectin. Rats fed 3% pectin were not different in any vitamin E parameters from those fed 0% pectin. By the end of the study body weights were significantly lower in the 6 and 8% pectin groups after adjusting for their nonsignificant trend of lower food intake. At wk 8, liver vitamin E levels were reduced in the 6 and 8% pectin group compared to values at the start of the study. Both groups had significantly higher red blood cell hemolysis compared to 0% pectin at 8 wk. Fecal fat excretion was not different among the diet groups, but weights of the small and large intestines were significantly increased in rats fed 6 or 8% pectin compared to those fed 0 or 3%. Our results show that 6 and 8 but not 3% dietary pectin decreased vitamin E availability in rats.

Lipid‐Soluble Vitamins in Blood and Liver of Rats Fed a Diet Containing Hard Red Spring Wheat Bran

“…Methylcellulose, agar, pectin or wheat bran added to the feed of rats at 10% level had a negative effect on vitamin absorption (Gronowska-Senger et al, 1979). In our laboratory, we found similar effects on the bioavailability of vitamin E in rats fed 8 to 10% pectin (de Lumen et al, 1982;Schaus et al, 1985), and a transient decrease in blood vitamin A or vitamin E after the ingestion of S-20% wheat bran (Omaye and Chow, 1984a, b).…”

“…The bioavailability of vitamin B12 and B6 is less when consumed with dietary fiber (Cullen and Oace, 1978;Leklem et al, 1980) and dietary fiber influences urinary excretion of ascorbic acid (Keltz et al, 1978). Recently, we found that plasma concentrations of vitamin E decreased significantly in rats fed high levels of pectin (deLumen et al, 1982) and some physiological alterations occurred at moderate intake (Schaus et al, 1985). Some transient decreases in plasma lipid-soluble vitamins also were found after rats were fed diets containing 20% wheat bran (Omaye and Chow, 1984a, b).…”

Simple method for bleeding the unanaesthetized rat by tail venipuncture

“…We feel that the method described has many advantages over other techniques and has applications to a variety of situations. Before development of the method for rat restraint, we found that bioavailability studies could be done by obtaining samples with the same venipuncture method when the rats were anaesthetized with methoxylfurane (Schaus et al, 1985;Omaye & Chow, 1984). However, anaesthetics may affect the results.…”

Bioavailability of Vitamin E

“…Studies in rats suggested that VE bioavailability was impaired by the presence of pectin (110,111). However, no effect of various fiber types (pectin, guar, alginate, cellulose or wheat bran) were observed on the mean increase of plasma α-tocopherol concentration over 24 h in women (112).…”