Chicken eggshell powder (ESP) might be an attractive source of Ca for human nutrition. To study its nutritional value, we analyzed minerals, amino acids, and hormones in commercially available Slovakian ESP. The mineral composition was compared with three Dutch ESP samples that differed in feed and housing, a Japanese ESP, refined CaCO3, and an oyster shell supplement. Chicken eggshell powder contains high levels of Ca (mean +/- SD/g EPS: 401+/-7.2 mg) and Sr (372+/-161 microg) when compared with recommended or estimated daily intakes for humans 51 to 70 yr of age. Levels of potentially toxic Pb, Al, Cd, and Hg were very low as were levels of V, B, Fe, Zn, P, Mg, N, F, Se, Cu, and Cr. Large differences in the levels of F, Se, Cu, Cr, and Sr in the Dutch and Slovakian ESP indicated a strong influence of feed and environment. The small protein fraction of ESP contains high levels of Gly and Arg. Furthermore, small amounts of transforming growth factor-beta1 (0.75 to 7.28 ng/g ESP), calcitonin (10 to 25 ng/g ESP), and progesterone (0.30 to 0.33 ng/g ESP) were detected. Estradiol-17beta and calcitriol were below the detection limit of the methods used. Compared with ESP, refined CaCO3 was found to contain increased levels of Cd, and the oyster shell supplement showed increased levels of Al and Cd. Therefore, ESP seems to have a beneficial composition with about 39% of elemental Ca, relevant amounts of Sr, and low levels of Al, Pb, Cd and Hg. It may be used as a Ca source in human nutrition.

For early prevention or inhibition of postmenopausal and age-related bone loss, nutritional interventions might be a first choice. For some vitamins and minerals an important role in bone metabolism is known or suggested. Calcium and vitamin D support bone mineral density and are basic components in most preventive strategies. Magnesium is involved in a number of activities supporting bone strength, preservation, and remodeling. Fluorine and strontium have bone-forming effects. However, high amounts of both elements may reduce bone strength. Boron is especially effective in case of vitamin D, magnesium, and potassium deficiency. Vitamin K is essential for the activation of osteocalcin. Vitamin C is an important stimulus for osteoblast-derived proteins. Increasing the recommended amounts (US RDA 1989), adequate intakes (US DRI 1997), or assumed normal intakes of mentioned food components may lead to a considerable reduction or even prevention of bone loss, especially in late postmenopausal women and the elderly.

Atrial natriuretic factor (ANF) lowers blood volume in intact and anephric experimental animals. The latter observation suggests extravasation of plasma at the level of the microcirculation. In view of the differential regional hemodynamic responses to ANF, the present study investigates possible regional differences in plasma extravasation measured as regional albumin clearances in skeletal muscle, lung, brain, ileum, and skin. In control animals, there were pronounced regional differences in clearances with highest values in ileum (0.248 +/- 0.015 microliter/min.g tissue) and lowest in brain (0.010 +/- 0.002 microliter/min.g tissue). Plasma-volume was 3.58 +/- 0.07 ml/100 g b.w. ANF (1 microgram/kg.min) significantly reduced plasma-volume (3.20 +/- 0.06 ml/100 g b.w.). This was associated with significantly increased albumin clearances in skeletal muscle and ileum, but not in other tissues examined. The data indicate that ANF increases albumin extravasation. This suggests that, besides effects on renal function and vascular tone, ANF also affects blood volume through influencing the relationship between intra- and extravascular volume.

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