Effekt einer Zulage an Citronensäure auf die Bioverfügbarkeit von Zink aus Maiskeimen

Abstract

The purpose of this 2 factorial designed study was to investigate the influence of citric acid on the availability of zinc from diets containing 140 g corn germs as a native phytate source (0.5% phytate in diet). Growing male rats with an average initial weight of 42 g were divided into 8 groups of 8 animals each. After a 7 d depletion period (2.4 micrograms Zn/g diet) the animals were fed ad libitum for 21 d a diet on the basis of egg white solid and corn germs. The diets were supplemented with zinc in order to obtain phytate:zinc molar ratios of 31, 20, 14, and 0 (control without corn germs, 11 micrograms Zn/g diet). Each diet was fed with and without a supplementation of 1% citric acid. A phytate:Zn molar ratio of 31:1 resulted in typical symptoms of zinc-deficiency like anorexia, alopecia and a significant depression of growth. These effects were apparently reduced by citric acid. The zinc concentration in serum and organs followed the graded levels of phytate:zinc molar ratios. Primary significant effects of the phytate:Zn molar ratio but also effects of citric acid and interactions between the 2 factors phytate:Zn and citric acid could be detected. Only total liver zinc but not liver zinc based on fresh matter was affected by the phytate:Zn molar ratio. In serum and tissues the activity of alkaline phosphatase showed a significant response to the phytate:zinc molar ratio. Furthermore the supplementation with citric acid increased the femur alkaline phosphatase and slightly reduced it in the liver. The concentrations of metallothionein in liver duodenum, jejunum and ileum were significantly affected by the phytate:Zn molar ratio.

The Role of Fe, Zn, and Cu in Pregnancy

“…The degree of bioavailability of Zn from food depends on the concentration of Zn in the body, stress [230,231], functional state of the kidneys [232] and/or liver [233], pH of the nutrient content [234]. The presence of citric acid [235], a high intake of animal proteins [236], the presence of highly processed products and lactose [237] have a positive influence on the bioavailability of Zn. Negative effects on Zn absorption are by heavy metals (cadmium and mercury), calcium, Fe, Cu, oxalates, phosphates, alcohol, folates, and phytates, alkaline drugs, contraceptives, and diuretics [238][239][240][241].…”

Effect of Citric Acid Supplements to a Maize‐Soya Diet on the in vitro Availability of Minerals, Trace Elements, and Heavy Metals

“…This precipitation was reduced after the addition of CTA, so that about 90 ' ' n of zinc in the neutralized extract was kept soluble. Furthermore there is some evidence that zinc citrate is effective in enhancing absorption of zinc in vivo (LONNERDAL et a]., 1980;PALLAUF et d., 1990). This finding might explain the high absorbability of zinc from human milk, which is naturally high in CTA (LONNERDAL et al, 1980).…”