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Protein intake and ovulatory infertility
Objective To evaluate whether intake of protein from animal and vegetable origin is associated with ovulatory infertility. Study Design 18,555 married women without a history of infertility were followed as they attempted a pregnancy or became pregnant during an eight 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% CI; P, trend) of ovulatory infertility comparing the highest to the lowest quintile of animal protein intake was 1.39 (1.01 – 1.90; 0.03). The corresponding RR (95% CI; P, trend) for vegetable protein intake was 0.78 (0.54 – 1.12; 0.07). Further, 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 = 0.007). Conclusions Replacing animal sources of protein with vegetable sources of protein may reduce ovulatory infertility risk.