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The effect of a self-selected and semisynthetic diet on urinary conjugates levels was determined in 18 male adults (22-40 y). Urinary conjugates were also quantified to develop an index of detoxification using a multivariate approach. The four major urinary conjugates measured were glucuronides, sulfoconjugates, mercapturates, and amino acid conjugates. Subjects consumed a self-selected diet for three days and a semisynthetic diet for seven days. Mercapturates and amino acid conjugates were most affected by dietary change, excretion levels reduced by about 50% during the semisynthetic diet period (0.27±0.11 vs 0.14±0.02 mmol/24-h; 5.99 vs 3.03 mmol/24-h, respectively). Glucuronides were the least responsive to dietary change with no significant difference between the means of the two diet periods (self-selected diet 2.93±0.77; semisynthetic 3.21±0.29 mmol/24-h). Four methods for developing 'normal' ranges were presented: mean±SD; percentiles; principal component analysis (princomp); Mahalanobis distance (distquan). The four methods were compared. In summary, conjugate excretion levels were found to be sensitive to dietary changes, with some pathways more responsive than others. Also, the princomp and distquan methods were stressed because they are a multivariate approach which combine values for all three pathways and their interaction into a single value that would then be representative of an individual's total, or overall, detoxification level relative to the others in this group. / Ph. D.

We examined the effect of daily stress, age, and emotional stability/neuroticism on stress reactivity, using cortisol diurnal rhythms. We used data from the Normative Aging Study (Spiro & Bosse, 2001). The 72 men in this study ranged from 67-93 (M =79.29, SD =4.88). Multilevel modeling showed that higher daily stress predicted flatter cortisol diurnal rhythms, B = .09, p < .001, as did age, B = .01, p < .001, while those higher in neuroticism on the emotional stability/neuroticism measure showed steeper slopes for cortisol diurnal rhythms, B = -.04, p < .001. These results indicate that age and emotional stability/neuroticism levels explain some of the variance in individual differences in stress reactivity and provide a basis for future research focused on the effects of psychosocial variables on physiological outcomes. / Graduation date: 2013