title: Protein intake and ovulatory infertility.
abstract: OBJECTIVE
  The objective of the study was to evaluate whether intake of protein from animal and vegetable origin is associated with ovulatory infertility.
  
  
  METHODS
  A total of 18,555 married women without a history of infertility were followed up as they attempted a pregnancy or became pregnant during an 8 year period. Dietary assessments were related to the incidence of ovulatory infertility.
  
  
  RESULTS
  During follow-up, 438 women reported ovulatory infertility. The multivariate-adjusted relative risk (RR) (95% confidence interval [CI]; P for trend) of ovulatory infertility comparing the highest to the lowest quintile of animal protein intake was 1.39 (1.01 to 1.90; 0.03). The corresponding RR (95% CI; P for trend) for vegetable protein intake was 0.78 (0.54 to 1.12; 0.07). Furthermore, consuming 5% of total energy intake as vegetable protein rather than as animal protein was associated with a more than 50% lower risk of ovulatory infertility (P =.007).
  
  
  CONCLUSIONS
  Replacing animal sources of protein with vegetable sources of protein may reduce ovulatory infertility risk.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA. jchavarr@hsph.harvard.edu
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Chavarro
authors.forename: Janet W
authors.initials: JW
authors.lastname: Rich-Edwards
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Rosner
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
mesh_terms: D000328:Adult; D004034:Diet Surveys; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D008460:Meat; D010060:Ovulation / Q000187:drug effects*; D014674:Plant Proteins, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States
chemical_list: D004044:Dietary Proteins; D014674:Plant Proteins, Dietary