Salivary alpha-amylase and hormones levels of young adults with different body composition.

The aim of this study was to assess the differences in salivary biomarker levels of young adults classified according to body fat accumulation. One hundred and thirty-four volunteers were evaluated (mean age 21 ± 2 years). Body composition was calculated through skinfold thickness: supra-iliac, biceps, and triceps, sub-scapular. Body fat percentage (BF%) was used to classify subjects according to fat tissue accumulation: normal-weight (n = 37, 19 females, 18 males), overweight (n = 42, 30 females, 12 males), and obese (n = 55, 42 females, 13 males). Saliva samples were collected 30 min after awakening to determine salivary levels of 17-beta-estradiol. For salivary cortisol and alpha-amylase activity (sAA) three samples were obtained, just after awakening, 30 min after awakening and at bedtime. Oral contraceptive intake was considered for the female group. The results showed that overweight and obese females using oral contraceptive presented lower levels of 17-β-estradiol than normal-weight females. In overweight and obese males, sAA levels were higher 30 min post-awakening when compared with the normal-weight group. The comparison of sAA levels within time showed no difference for males; obese females showed significant higher values at bedtime than 30 min post-awakening. The salivary cortisol concentration showed higher values at morning decreasing significantly at bedtime for all groups. Concluding, differences in 17-β-estradiol and sAA levels were found in females and males, respectively, according to body fat accumulation, showing the usefulness of salivary biomarkers in the study of systemic conditions. PRACTICAL APPLICATIONS: Saliva is an advantageous biological fluid in innovative methods for diagnosis. Besides being a noninvasive method, salivary steroid measurements have the potential to provide a convenient assessment of serum free steroid concentrations.