title: Energy intake and leukocyte telomere length in young adults.
abstract: BACKGROUND
  Dietary energy restriction in mammals, particularly at a young age, extends the life span. Leukocyte telomere length (LTL) is thought to be a bioindicator of aging in humans. High n-6 (omega-6) PUFA intake may accelerate LTL attrition.
  
  
  OBJECTIVE
  We determined whether lower energy and higher PUFA intakes in young adulthood are associated with shorter LTL in cross-sectional and longitudinal analyses.
  
  
  METHODS
  In a longitudinal observational study (405 men, 204 women), diet was determined at baseline by a semiquantitative food-frequency questionnaire, and LTL was determined by Southern blots at mean ages of 30.1 y (baseline) and 43.2 y (follow-up). Spearman correlations and multivariable linear regression were used.
  
  
  RESULTS
  Baseline energy intake was inversely associated with follow-up LTL in men (standardized β = -0.171, P = 0.0005) but not in women (P = 0.039 for sex interaction). The difference in men between the highest and lowest quintiles of energy was 244 base pairs (bp) (95% CI: 59, 429 bp) and between extreme quintiles of LTL was 440 kcal (95% CI: 180, 700 kcal). Multivariable adjustment modestly attenuated the association (β = -0.157, P = 0.002). Inverse associations, which were noted for all macronutrients, were strongest for the unsaturated fatty acids. In multivariable models including energy and the macronutrients (as percentage of energy), the significant inverse energy-LTL association (but not the PUFA-LTL association) persisted. The energy-LTL association was restricted to never smokers (standardized β = -0.259, P = 0.0008; P = 0.050 for the smoking × calorie interaction).
  
  
  CONCLUSIONS
  The inverse calorie intake-LTL association is consistent with trial data showing beneficial effects of calorie restriction on aging biomarkers. Further exploration of energy intake and LTL dynamics in the young is needed.
authors.affiliation: Hebrew University-Hadassah School of Public Health and Community Medicine, Ein Kerem, Jerusalem, Israel. jeremy1@vms.huji.ac.il
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Kark
authors.forename: Nehama
authors.initials: N
authors.lastname: Goldberger
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kimura
authors.forename: Ronit
authors.initials: R
authors.lastname: Sinnreich
authors.forename: Abraham
authors.initials: A
authors.lastname: Aviv
mesh_terms: D000328:Adult; D000375:Aging / Q000235:genetics / Q000502:physiology*; D020029:Base Pairing; D015415:Biomarkers; D015139:Blotting, Southern; D003430:Cross-Sectional Studies; D004032:Diet; D004034:Diet Surveys; D002149:Energy Intake; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000648:ultrastructure*; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D012737:Sex Factors; D012907:Smoking; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D016615:Telomere / Q000648:ultrastructure*
chemical_list: D015415:Biomarkers; D005231:Fatty Acids, Unsaturated