PLASMA ZINC RESPONSE TO A BREAKFAST MEAL OR FASTING IN ELDERLY WOMEN

The aim of this study was to determine whether the postprandial declin e in plasma zinc concentration is altered by aging. Eleven women, betw een the ages of 65 and 82 yr, participated in two separate experimenta l protocols: a high carbohydrate breakfast trial and a fasting trial. Plasma zinc concentrations were measured from blood samples obtained a t 8:00 AM (baseline fasting) and at 30-min intervals until 1:00 PM dur ing each trial. Following the breakfast meal, plasma zinc concentratio ns declined 14% from 75 +/- 1 to 65 +/- 2 mu g/dL (p < 0.05), reaching a nadir 2.7 +/- 0.2 h after the meal. This decline was significantly (p < 0.0001) greater than the 3.6% fall observed during the fasting tr ial. Postprandial changes in the plasma zinc concentrations were corre lated with postprandial changes in serum glucose (r = -0.43, p < 0.001 ), serum insulin (r = -0.17, p < 0.01), and serum phosphorus(r = 0.32, p < 0.005). These data show that plasma zinc concentrations decline f ollowing food intake in elderly women in the same manner as previously described for younger adult women.