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Effect of High Protein Consumption on Markers of B 6 Status in a Rodent Model of Moderate Pyridoxine Deficiency
Author(s) -
RaposoBlouw Sara,
Mayengbam Shyamchand,
House James
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.134.4
Subject(s) - pyridoxal , weanling , pyridoxine , medicine , endocrinology , chemistry , carbohydrate , pyridoxal phosphate , enzyme , biochemistry , biology , cofactor
Pyridoxal‐5‐phosphate (PLP) is the active form of pyridoxine (PN; B 6 ). Increasing protein intake may affect B 6 status by increasing PLP‐dependent enzymes in amino acid metabolism. These impacts may be more pronounced during moderate B 6 deficiency, which is observed in 25% of North Americans. To this end, we examined the impact of changing the dietary carbohydrate:protein ratio in rodents consuming recommended vs. moderately deficient intakes of PN‐HCl, on plasma markers of B 6 status. Weanling male Sprague‐Dawley rats (n=8/group) were randomized to one of four dietary groups for five weeks. A two factorial design used two levels of B 6 (marginally deficient (MD): 0.7 vs. adequate (A): 7.0 mg PN‐HCl/kg diet), and two defined ratios of carbohydrate to protein: 60%: 20% (AIN‐93 standard; NP); and 40%: 40% (high protein diet; HP), with dietary fat held constant. Plasma B 6 vitamers, including PN, pyridoxal (PL), PLP, and 4‐pyridoxic Acid (PA) were analyzed by reverse‐phase high‐pressure liquid chromatography in dark conditions. Decreasing dietary B 6 intake significantly depressed all plasma B 6 vitamers. Increasing dietary protein intake significantly depressed plasma PN (A‐NP=235; A‐HP=203; MD‐NP=181; MD‐HP=90 nM; SEM =21.8 nM). There were no significant interactions evident. Other markers of B 6 status, including plasma homocysteine, were not significantly impacted. The current data provide evidence of an increased conversion of PN to PLP in the face of an increased dietary protein load. However, under moderate B 6 deficient conditions, consuming high amounts of protein similar to the upper acceptable macronutrient distribution range does not significantly exacerbate B 6 deficiency.