title: Increased oxidative stress in younger as well as in older humans.
abstract: BACKGROUND
  The free radical theory of aging is based upon the adverse effects of oxidative stress (OS), and indices of OS generally increase with advancing age. However, since OS may also be a normal physiological response in youth, when reactive oxygen species (ROS) act as signal transducers during normal growth and development, we compared markers of OS in normal humans over a wide spectrum of different ages.
  
  
  METHODS
  Fasting breath samples were collected from 102 healthy volunteers (age 9 to 89 years) and volatile organic compounds (VOCs) were assayed by gas chromatography and mass spectroscopy. The intensity of OS in each volunteer was estimated by the breath methylated alkane contour (BMAC), a three-dimensional display of the abundance of C4-C20 alkanes and monomethylated alkanes. The collective abundance of these VOCs in a breath sample was reduced to a single value, the volume under curve (VUC), and correlated with chronological age.
  
  
  RESULTS
  Compared to subjects aged 20-40 years, the mean BMAC VUC was significantly increased in subjects aged < 20 (p < 0.0001) and >40 years (p < 0.001). A cubic function correlated BMAC VUC (x) with chronological age (y): y = 33.7 - 3.29x + 0.072x(2) - 0.0004x(3) (r = 0.48).
  
  
  CONCLUSIONS
  Breath markers of OS were significantly increased both in younger and in older subjects, compared to those aged 20-40 years. Increased OS in older subjects was consistent with previous reports, but increased OS in younger subjects aged < 20 years is a new observation; this may be a normal physiological response in youth.
authors.affiliation: Menssana Research Inc, 1 Horizon Road, Suite 1415, Fort Lee, NJ 07024, USA. menssana@bellatlantic.net
authors.forename: Michael
authors.initials: M
authors.lastname: Phillips
authors.forename: Renee N
authors.initials: RN
authors.lastname: Cataneo
authors.forename: Joel
authors.initials: J
authors.lastname: Greenberg
authors.forename: Ratnasiri
authors.initials: R
authors.lastname: Gunawardena
authors.forename: Farid
authors.initials: F
authors.lastname: Rahbari-Oskoui
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001944:Breath Tests; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress