Undernutrition is a stressor with long-term consequences, and the effect of nutritional recovery on cortisol and thyroid hormone status is unknown. To investigate basal thyroid hormones and the cortisol response to a cold pressor test in children recovered from undernutrition, a cross-sectional study was undertaken on children (6–16 years) separated into four groups: control (n 41), stunted (n 31), underweight (n 27) and recovered (n 31). Salivary cortisol was collected over the course of 10 h: upon awakening, before and after an unpleasant and a pleasant stimulus. Cortisol upon awakening was highest in the stunted and lowest in the underweight groups: control=5·05 (95 % CI 3·71, 6·89) nmol/l, stunted=6·62 (95 % CI 3·97, 11·02) nmol/l, underweight=2·51 (95 % CI 1·75, 3·63) nmol/l and recovered=3·46 (95 % CI 2·46, 4·90) nmol/l (P=0·005). Girls had higher cortisol concentrations upon awakening compared with boys (P=0·021). The undernourished groups showed an elevated cortisol response both to the unpleasant stimulus and at the last measurement (16.00 hours) compared with that of the recovered group: AUC, control=2·07 (95 % CI 1·69, 2·45) nmol/l×30 min, stunted=2·48 (95 % CI 1·91, 3·06) nmol/l×30 min, underweight=2·52 (95 % CI 2·07, 2·97) nmol/l×30 min, recovered=1·68 (95 % CI 1·26, 2·11) nmol/l×30 min (P=0·042); and control=2·03 (95 % CI 1·75, 2·39) nmol/l×30 min, stunted=2·51 (95 % CI 1·97, 3·19) nmol/l×30 min, underweight=2·61 (95 % CI 2·16, 3·16) nmol/l×30 min, recovered=1·70 (95 % CI 1·42, 2·03) nmol/l×30 min (P=0·009). Lower free thyroxine (T4) was found in the recovered and stunted groups: control=1·28 (95 % CI 1·18, 1·39) pmol/l, stunted=0·98 (95 % CI 0·87, 1·10) pmol/l, underweight=1·10 (95 % CI 1·01, 1·21) pmol/l and recovered=0·90 (95 % CI 0·83, 0·99) pmol/l (P<0·001). Multivariate analysis showed a lower cortisol concentration along 10 h (06.00–16.00 hours) in the recovered compared with the other groups (P=0·017), and similar concentrations between the recovered and control group. In conclusion, the children with recovery in weight and height had a cortisol stress response similar to control but a lower basal free T4. Longitudinal studies are warranted to determine the extent of these endocrine changes after recovery of undernutrition and in adulthood.

The effects of Se on thyroid metabolism in a New Zealand population are investigated, including (a) the relationship between Se and thyroid status, and (b) the effect of Se supplementation on thyroid status. The data used come from two cross-sectional studies of Se, I, thyroid hormones and thyroid volume (studies 1 and 4), and three Se intervention studies in which thyroid hormones, Se and glutathione peroxidase (GPx) activities were measured (studies 2, 3 and 5). There were no significant correlations between Se status and measures of thyroid status after controlling for sex at baseline or after supplementation in any of the studies. When data from study 4 were divided into two groups according to plasma Se, plasma thyroxine (T4) was lower in males with higher plasma Se levels (P=0·009). Se supplementation increased plasma Se and GPx activity, but produced only small changes in plasma T4 and triiodothyronine (T3):T4 ratio. In study 2, there was a significant reduction in plasma T4 (P=0·0045). In studies 3 and 5 there were small decreases in plasma T4 and a small increase in the T3:T4 ratio, which were not significantly different from placebo groups. Lack of significant associations between plasma Se and thyroid status, and only small changes in T4 suggest that Se status in New Zealand is close to adequate for the optimal function of deiodinases. Adequate plasma Se may be approximately 0·82–0·90 μmol/l, compared with 1·00–1·14 μmol/l for maximal GPx activities.

The plasma glucose–insulin relationships and thyroid status were investigated in two lines of adult cockerels divergently selected for high (R+) or low (R-) residual food consumption (RFC). For a given body weight, R+ birds had a 74 % higher food intake than R- birds. Plasma glucose concentrations were significantly lower in the R+ line compared with the R- when fasted, whereas R+ birds exhibited a significantly lower plasma insulin concentration than R- birds either in fed or fasted state. After an overnight fast, R+ birds also exhibited a higher sensitivity to exogenous insulin in view of its more pronounced hypoglycaemic effect. After an oral glucose load, the glucose disposal of R+ cockerels was faster despite lower glucose-induced plasma insulin concentration. Whilst plasma triacylglycerol concentrations were lower in the R+ line when fed, plasma non-esterified fatty acid concentrations were higher in fasted R+ than R- cockerels (684 v. 522 μmol/l). Higher plasma triiodothyronine concentrations were observed in fed R+ compared with R- birds (3·0 v. 2·1 nmol/l respectively). The higher plasma concentrations of triiodothyronine associated with lower concentrations of insulin could account for the leanness and the elevated diet-induced thermogenesis previously observed in the R+ line.