Apparent absorption of eight micronutrients and phytic acid from vegetarian meals in ileostomized human volunteers

Abstract

Objectives: Apparent absorption of eight micronutrients and degradation of phytic acid were studied in human subjects who underwent ileostomy. The prominent factors affecting micronutrient absorption from vegetarian Indian meals (n = 11) were identified.

Methods: Levels of beta-carotene, ascorbic acid, riboflavin, and thiamine in food and ileostomy contents were estimated by spectrophotometry and spectrofluorometry. Contents of zinc, iron, copper, and manganese were estimated by atomic absorption spectrometry and that of phytic acid by gradient elution ion exchange chromatography. Statistical analyses were done with SPSS 10.0.

Results: Absorption of beta-carotene, ascorbic acid, riboflavin, and thiamine was 63% to 75.6%. There was a negative non-significant trend in values of beta-carotene absorption with increased intake of beta-carotene (r = - 0.51, P > 0.1) and iron (r = -0.67, P = 0.1) but a positive significant trend with riboflavin intakes (r = 0.84, P = 0.018). Percentage of absorption of ascorbic acid showed weak positive associations with intakes of riboflavin (r = 0.71) and ascorbic acid (r = 0.5). Percentage of absorption of ascorbic acid was positively correlated with percentage of absorption of beta-carotene (r = 0.80, P < 0.05), iron, and riboflavin (r = 0.64, P = 0.086), indicating some common influencing factors. Percentages of absorption for zinc (20.2), iron (9.9), and copper (17.6) was comparable with those reported for soy protein-based, high phytate diets. Pattern of phytic acid in the meals and output indicated partial degradation and absorption (34%).

Conclusions: For vegetarian Indian meals, apparent absorptions of beta-carotene and ascorbic acid were 76% and 73.5% and of riboflavin and thiamine was 63%. Zinc, copper, and iron showed a lower absorption (10% to 20%).