Moving beyond inclusion: Methodological considerations for the menstrual cycle and menopause in research evaluating effects of dietary nitrate on vascular function

Nitric Oxide. 2022 Jan 1;118:39-48. doi: 10.1016/j.niox.2021.11.001. Epub 2021 Nov 11.

Abstract

Recent reports have acknowledged the underrepresentation of women in the field of dietary nitrate (NO3-) research. Undoubtedly, greater participation from women is warranted to clarify potential sex differences in the responses to dietary NO3- interventions. However, careful consideration for the effects of sex hormones - principally 17β-estradiol - on endogenous nitric oxide (NO) synthesis and dietary NO3- reductase capacity is necessary for improved interpretation and reproducibility of such investigations. From available literature, we present a narrative review describing how hormonal variations across the menstrual cycle, as well as with menopause, may impact NO biosynthesis catalyzed by NO synthase enzymes and NO3- reduction via the enterosalivary pathway. In doing so, we address methodological considerations related to the menstrual cycle and hormonal contraceptive use relevant for the inclusion of premenopausal women along with factors to consider when testing postmenopausal women. Adherence to such methodological practices may explicate the utility of dietary NO3- supplementation as a means to improve vascular function among women across the lifespan.

Keywords: Cardiovascular; Exercise; Flow-mediated dilation; Nitric oxide.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Biomedical Research / methods*
  • Dietary Supplements
  • Estradiol / metabolism
  • Female
  • Humans
  • Menopause / drug effects*
  • Menopause / metabolism
  • Menstrual Cycle / drug effects*
  • Menstrual Cycle / metabolism
  • Nitrates / pharmacology*
  • Nitric Oxide / biosynthesis
  • Nitric Oxide / metabolism
  • Sex Factors

Substances

  • Nitrates
  • Nitric Oxide
  • Estradiol