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Neomycin has no persistent sparing effect on vitamin B-12 status in pectin-fed rats
1Department of Nutritional Sciences, University of California, Berkeley 94720.
The Journal of Nutrition
|October 1, 1989
Summary
Pectin negatively impacts vitamin B-12 status in rats, independent of neomycin-sensitive bacteria. This suggests pectin may directly hinder vitamin B-12 absorption or alter microbial metabolism.
Area of Science:
- Nutrition Science
- Microbiology
- Biochemistry
Background:
- Dietary pectin has been observed to negatively affect vitamin B-12 status.
- The role of gut bacteria in this interaction remains unclear.
Purpose of the Study:
- To investigate if bacterial fermentation of pectin mediates its negative effects on vitamin B-12 status in rats.
- To determine if the antibiotic neomycin can mitigate pectin's impact on vitamin B-12 metabolism.
Main Methods:
- Rats were fed fiber-free or pectin-containing diets, with or without neomycin, to induce vitamin B-12 depletion.
- Measurements included urinary methylmalonate, propionate oxidation, and the biologic half-life of injected vitamin B-12 ([57Co]vitamin B-12).
Main Results:
- Neomycin did not prevent pectin's negative effects on vitamin B-12 metabolism.
- Pectin significantly increased urinary methylmalonate and decreased propionate oxidation, effects exacerbated by neomycin.
- Pectin shortened the biologic half-life of vitamin B-12, irrespective of neomycin presence.
Conclusions:
- Neomycin-sensitive bacteria do not mediate the adverse effects of pectin on vitamin B-12 status.
- Pectin likely interferes directly with vitamin B-12 absorption or alters the metabolism of neomycin-adapted microbes.