Protein intake and ovulatory infertility.
Level 3 - non-randomized controlled study
Prospective cohort study
PubMed 18226626 · doi:10.1016/j.ajog.2007.06.057
What was done
A prospective cohort of 18,555 married women without a history of infertility was followed for 8 years as they attempted pregnancy or became pregnant. Dietary intake of animal and vegetable protein was assessed in relation to incident ovulatory infertility using multivariate-adjusted relative risks (RR).
What was found
During follow-up, 438 women reported ovulatory infertility. Comparing the highest to lowest quintile of animal protein intake, the multivariate-adjusted RR of ovulatory infertility was 1.39 (95% CI, 1.01 to 1.90; P for trend = 0.03). For vegetable protein intake, the RR comparing highest to lowest quintile was 0.78 (95% CI, 0.54 to 1.12; P for trend = 0.07). Substituting 5% of total energy intake as vegetable protein rather than animal protein was associated with a >50% lower risk of ovulatory infertility (P = 0.007).
Why it matters
This study suggests that dietary protein source is associated with ovulatory function, and replacing animal protein with plant protein may help reduce the risk of ovulatory infertility.
Limits
The observational design cannot establish causality and remains subject to unmeasured confounding. Dietary intake and infertility outcomes were self-reported, and the study was restricted to married women attempting pregnancy.
Cited by
- supports Replacing servings of animal protein with plant-based protein is associated with improved ovulation and higher fertility rates.