Brittmarie Sandström

Zinc absorption in adult humans : the effect of iron fortification

The effect of Fe fortification on the absorption of Zn was studied by radioisotopic labelling of single meals, followed by measurements of whole-body retention of 65Zn at 14 d after intake. Healthy adult volunteers participated in the study. Weaning cereal, wheat bread and infant formula, foods that are all frequently Fe-fortified, were evaluated in the study. The amounts of Fe added as FeSO4 were similar to the levels in commercial products in Europe and the USA, and were 200 or 500 mg Fe/kg (weaning cereal), 65 mg Fe/kg (white wheat flour) and 12 mg Fe/l (infant formula). For comparison, Zn absorption was measured in the same subjects, from identical test meals containing no added Fe. No statistically significant differences were found when Zn absorption from the Fe-fortified test meals was compared with that from non-Fe-fortified test meals. Fractional Zn-absorption values from Fe-fortified v. non-fortified meals were 31.1 (SD 11.9) v. 30.7 (SD 7.0)% (weaning cereal; 200 mg Fe/kg), 37.7 (SD 16.6) v. 30.2 (SD 9.9)% (weaning cereal; 500 mg Fe/kg), 36.5 (SD 14.4) v. 38.2 (SD 18.1)% (bread; 65 mg Fe/kg flour) and 41.6 (SD 8.1) v. 38.9 (SD 14.5)% (infant formula; 12 mg Fe/l). The addition of Fe to foods at the currently used fortification levels was thus not associated with impaired absorption of Zn and the consumption of these Fe-fortified foods would not be expected to have a negative effect on Zn nutrition.

Extrusion cooking of a high-fibre cereal product 2. Effects on apparent absorption of zinc, iron, calcium, magnesium and phosphorus in humans

1. The effect of extrusion cooking, using mild conditions, of a high-fibre cereal product on apparent small bowel absorption of zinc, iron, calcium, magnesium and phosphorus was studied. 2. Seven ileostomy subjects were studied during two periods (each of 4 d), on a constant low-fibre diet supplemented with either 54 g/d of a bran-gluten-starch mixture or the corresponding extruded product. 3. The apparent absorption of Zn, Mg and P was significantly decreased (P less than 0.05) during the period with extruded product compared with the period with bran-gluten-starch. No difference was found for Fe and Ca. 4. The negative effect of extrusion cooking of a product containing phytic acid on availability of Zn, Mg and P was small but could be of nutritional relevance in foodstuffs that are consumed frequently and in infant formulas.

The effect of different prosthetic restorations on the dietary selection in edentulous patients: A longitudinal study of patients initially treated with optimal complete dentures and finally with tissue-integrated prostheses

The effect of prosthetic restoration of masticatory ability on dietary selection was evaluated in 23 edentulous patients with denture adaptation problems. The patients were first given optimal complete dentures and then a fixed prosthesis on tissue-integrated implants in the lower jaw. Changes in dietary selection were evaluated from 4-day records obtained before prosthetic treatment and on six occasions up to 78 months after treatment. With the method used, no significant changes in food selection were recorded during the rehabilitation period, except for a slight increase in intake of crisp bread and fresh fruit after treatment with fixed tissue-integrated prostheses in the mandibular jaw. It is concluded that an improved oral function will not in itself lead to a change in dietary selection and that dietary changes probably require professional and individually given dietary advice by a trained dietitian.

Manganese absorption from mangold (Beta vulgaris): comparison of intrinsic and extrinsic labels

Abstract The validity of the use of extrinsic labeling for studies of manganese absorption in man was evaluated using a test meal containing Beta vulgaris intrinsically labeled with 54 Mn to which 52 Mn was added extrinsically. Whole body retention of the two isotopes was measured in a whole body counter during days 7–25 after administration of the test meal to six subjects. No difference in level of retention or rate of excretion was observed for the two isotopes. The calculated absorption ( X = SD ) was 6.0 ± 3.4% and 6.2 ± 2.9% for 54 Mn and 52 Mn, respectively, resulting in a 54 Mn : 52 Mn ratio for fractional absorption from the test meal of 0.95 ± 0.14 ( X ± SD ). These results demonstrate that extrinsic labeling with radioisotopes of manganese is a valid method for measurement of manganese absorption from vegetables when studied in humans.

Effect of Long-Term Trace Element Supplementation on Blood Trace Element Levels and Absorption of 75Se, 54Mn and 65Zn

A vitamin and trace element supplement containing recommended dietary amounts or safe and adequate levels was given to ten healthy subjects for 12 to 35 weeks. Plasma levels of selenium and zinc, activity of glutathione peroxidase in plasma and platelets, whole blood manganese, activity of superoxide dismutase in hemolysate, activity of alkaline phosphatase in serum, iron status indices and urinary excretion of zinc and selenium were measured. A small but significant change in plasma selenium from 1.01 +/- 0.14 mumol/L to 1.08 +/- 0.10 mumol/L was observed after two weeks. However, at the end of the supplementation plasma selenium levels did not differ from the initial levels. Plasma glutathione peroxidase levels showed a similar trend and changes in glutathione peroxidase activity in platelets were also transient. A small increase in serum zinc values was observed after 30 weeks of supplementation. No significant changes were observed in the other blood and urine parameters studied. In seven of the subjects absorption of zinc, manganese and selenium was measured after 30-31 weeks of supplementation by a radionuclide technique. The absorption of selenium and manganese after long term supplementation was 30-50% lower than observed previously in non-supplemented subjects. In conclusion, present available indices of trace element status are only to a limited extent affected by 30 weeks of a doubling of the normal dietary intake.