Iron Deficiency Reduces the Efficacy of Tryptophan as a Niacin Precursor

Abstract

A niacin-deficient purified amino acid diet that contained adequate (40 mg/kg) or deficient (10 or 15 mg/kg) iron was used to assess the growth promoting efficacy of tryptophan as a niacin precursor. Basal diets contained 1400 mg/kg tryptophan, a level that was established as meeting the requirement for tryptophan per se in diets containing excess nicotinic acid. Chicks fed the iron-deficient diets had markedly lower hemoglobin concentrations than those fed the iron-adequate diets. Regardless of iron level, chicks exhibited linear growth responses to either nicotinic acid or tryptophan supplementation. Using multiple-linear regression of weight gain on supplemental tryptophan or nicotinic acid intake, the efficiency (wt:wt) of tryptophan conversion to niacin activity (i.e., tryptophan slope divided by nicotinic acid slope) was a mean of 1.77% (56:1) for chicks fed the iron-deficient diet. This was significantly (P < 0.05) lower than the 2.39% (42:1) efficiency calculated for chicks fed the iron-adequate diet. Thus, iron deficiency reduced tryptophan utilization (for NAD synthesis) but had no effect on nicotinic acid utilization. The results suggest that pellagra in populations having endemic anemia and protein-energy malnutrition may be due not only to inadequate intakes of bioavailable niacin but also to inadequate intakes of bioavailable iron.

Serum electrolytes in hospitalized pellagra alcoholics

“…In accordance with our results, hypoalbuminaemic patients ordinarily stay longer time in hospital and show increased mortality (Cunha et al, 1999). Higher anaemia frequency among malnourished pellagra could, at least partially, be caused by inadequate intake of bioavailable iron, in accordance with high iron de®ciency among malnourished alcoholics, and reduced tryptophan utilisation as a niacin precursor in iron de®ciency (Oduho et al, 1994).…”

Animal Models in Nutrition Research ,

“…Also, vitamin D is required for efficient absorption of both Ca and P. The interactions between Zn and Cu; Mo and Cu; Zn and Fe; cysteine or ascorbate and Cu, Zn, or Fe; Mn and P; Se and vitamin E; I and Br; As and cysteine; phytates or oxylates and several macro-and micromineral elements have been identified and help explain the utilization efficiencies of mineral elements in various foods (3). Among the vitamins, animals were used to help us understand the tryptophan 3 niacin and lysine 3 niacin interactions (4,5) as well as the effect of Fe deficiency on the conversion efficiency of tryptophan to niacin (6). Also, progress in solving pellagra in humans was held back for many years because of lack of a suitable animal model.…”

Association between NAD+ levels and anaemia among women in community‐based study

“…A study in rhesus monkey found that the NAD metabolites were similar between IDA and control groups, and NAD pathway components nearly doubled after the treatment of IDA 34 . Another study in male chicks found that iron deficiency reduced the utilization of tryptophan with which de novo biosynthesis of NAD starts 35,36 . Haemolytic anaemia could be induced by medications along with other causes, whose late diagnosis could be fatal 37 .…”

“…34 Another study in male chicks found that iron deficiency reduced the utilization of tryptophan with which de novo biosynthesis of NAD starts. 35,36 Haemolytic anaemia could be induced by medications along with other causes, whose late diagnosis could be fatal. 37 Nicotinamide mononucleotide adenylyltransferase 3 (Nmnat3) is considered a NAD synthesis enzyme involved in de novo and salvage pathways.…”