Women of childbearing age are at risk of Fe deficiency if insufficient dietary Fe is available to replace menstrual and other Fe losses. Haem Fe represents 10 -15 % of dietary Fe intake in meat-rich diets but may contribute 40 % of the total absorbed Fe. The aim of the present study was to determine the relative effects of type of diet and menstrual Fe loss on Fe status in women. Ninety healthy premenopausal women were recruited according to their habitual diet: red meat, poultry/fish or lacto-ovo-vegetarian. Intake of Fe was determined by analysing 7 d duplicate diets, and menstrual Fe loss was measured using the alkaline haematin method. A substantial proportion of women (60 % red meat, 40 % lacto-ovo-vegetarian, 20 % poultry/fish) had low Fe stores (serum ferritin ,10 mg/l), but the median serum ferritin concentration was significantly lower in the red meat group (6·8 mg/l (interquartile range 3·3, 16·25)) than in the poultry/fish group (17·5 mg/l (interquartile range 11·3, 22·4) (P,0·01). The mean and standard deviation of dietary Fe intake were significantly different between the groups (P¼ 0·025); the red meat group had a significantly lower intake (10·9 (SD 4·3) mg/d) than the lacto-ovo-vegetarians (14·5 (SD 5·5) mg/d), whereas that of the poultry/fish group (12·8 (SD 5·1) mg/d) was not significantly different from the other groups. There was no relationship between total Fe intake and Fe status, but menstrual Fe loss (P¼ 0·001) and dietary group (P¼ 0·040) were significant predictors of Fe status: poultry/fish diets were associated with higher Fe stores than lacto-ovo-vegetarian diets. Identifying individuals with high menstrual losses should be a key component of strategies to prevent Fe deficiency.

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Objective: To measure the bioavailability of selenium from cooked and raw fish in humans by estimating and comparing apparent absorption and retention of selenium in biosynthetically labelled fish with labelled selenate and biosynthetically labelled selenium in brewers yeast. Design: The intervention study was a parallel, randomised, reference substance controlled design carried out at two different centres in Europe. Setting: The human study was carried out at the Institute of Food Research, Norwich, UK and at TNO Nutrition and Food Research, Zeist, The Netherlands. Subjects: In all, 35 male volunteers aged 18-50 y were recruited; 17 subjects were studied in Norwich (UK) and 18 in Zeist (Netherlands). All of the recruited subjects completed the study. Interventions: Biosynthetically labelled trout fish (processed by two different methods), biosynthetically labelled brewers yeast and isotopically labelled selenate were used to estimate selenium apparent absorption and retention by quantitative analysis of stable isotope labels recovered in faeces and urine. Subjects consumed the labelled foods in four meals over two consecutive days and absorption was measured by the luminal disappearance method over 10 days. Urinary clearance of isotopic labels was measured over 7 days to enable retention to be calculated. Results: Apparent absorption of selenium from fish was similar to selenate and there was no difference between the two processing methods used. However, retention of fish selenium was significantly higher than selenate (Po0.001). Apparent absorption and retention of yeast selenium was significantly different (Po0.001) from both fish selenium and selenate. Conclusion: Fish selenium is a highly bioavailable source of dietary selenium. Cooking did not affect selenium apparent absorption or retention from fish. Selenium from yeast is less bioavailable.

The study of Cu metabolism is hampered by a lack of sensitive and specific biomarkers of status and suitable isotopic labels, but limited information suggests that Cu homeostasis is maintained through changes in absorption and endogenous loss. The aim of the present study was to employ stable-isotope techniques to measure Cu absorption and endogenous losses in adult men adapted to low, moderate and high Cu-supplemented diets. Twelve healthy men, aged 20 -59 years, were given diets containing 0·7, 1·6 and 6·0 mg Cu/d for 8 weeks, with at least 4 weeks intervening washout periods. After 6 weeks adaptation, apparent and true absorption of Cu were determined by measuring luminal loss and endogenous excretion of Cu following oral administration of 3 mg highly enriched 65 Cu stable-isotope label. Apparent and true absorption (41 and 48 % respectively) on the low-Cu diet were not significantly different from the high-Cu diet (45 and 48 % respectively). Endogenous losses were significantly reduced on the low-(0·45 mg/d; P,0·001) and medium-(0·81 mg/d; P¼0·001) compared with the high-Cu diet (2·46 mg/d). No biochemical changes resulting from the dietary intervention were observed. Cu homeostasis was maintained over a wide range of intake and more rapidly at the lower intake, mainly through changes in endogenous excretion.

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