This Korean rat study fed a zinc-deficient diet, a zinc-adequate diet, or the adequate diet in pair-fed amounts, to compare deficiency effects with the effects of reduced food intake. Zinc-deficient rats ate less, grew less and had lower alkaline phosphatase activity in plasma, liver, kidney and small intestine. Tissue calcium and magnesium were also lower in some tissues.
Key numbers
- Analyzed diet zinc: 0.3 ± 0.1 mg/kg in the deficient diet and 35.1 ± 12.9 mg/kg in the adequate and pair-fed diets (nominal 1 and 35 mg/kg) (Methods, p. 114).
- Final body weight: 347.8 ± 5.2 g (zinc-adequate), 225.0 ± 3.9 g (pair-fed), 219.7 ± 2.5 g (zinc-deficient) at day 42 (Table 1, p. 115).
- Liver calcium 121.9 ± 5.0 µg/g dry tissue (adequate) vs 68.0 ± 6.4 (deficient); muscle magnesium 188.3 ± 0.3 vs 48.5 ± 14.7 µg/g (Table 2, p. 116).
- Zinc recovery from NIST SRM 1577b bovine liver 97.3 ± 8.0% (Methods, p. 114).
Methods (brief)
Four-week-old rats were housed individually and fed modified AIN-76 diets for the study period, with a pair-fed group matched to the intake of deficient rats. Alkaline phosphatase was measured spectrophotometrically and minerals by inductively coupled plasma spectrometry after digestion. Groups were compared by one-way ANOVA with Tukey tests.
Evidence fitness
The paper supports animal evidence that dietary zinc deficiency, independent of reduced food intake, lowers alkaline phosphatase and some tissue mineral concentrations. It is not evidence on human requirements, excess intake, or food levels.
Limitations
The abstract states 10 weeks of feeding and an ICP-MS method, while Table 1 covers 42 days and the methods describe an ICP spectrometer. Tissue mineral results use only 3 to 4 rats per group. The protein source was changed partway through the study.
Related evidence
Update history
No substantive edit history is available in this build. The full commit record is available in git.