Dairy intake and fecundability in 2 preconception cohort studies

Area of Science:

• Reproductive Epidemiology
• Nutritional Science
• Human Fertility Studies

Background:

• Animal studies suggest high galactose intake may increase ovarian toxicity.
• Epidemiologic data on dairy intake and human fertility are limited and conflicting.

Purpose of the Study:

• To prospectively evaluate the relationship between dairy consumption and fecundability in women planning pregnancy.

Main Methods:

• Prospective cohort studies in Denmark (Snart Foraeldre) and North America (PRESTO).
• Validated food-frequency questionnaires used to assess dietary intake.
• Fecundability ratios (FRs) estimated using regression models adjusted for confounders in 2426 women.

Main Results:

• Total dairy intake showed a modest, inconsistent association with fecundability across cohorts (pooled FR: 1.11).
• Elevated FR for dairy in one cohort was linked to milk consumption in younger women (<30 years).
• No clear association found for low- or high-fat dairy; phosphorus and lactose intake showed slight positive correlations with fecundability.

Conclusions:

• Dairy intake associations with fecundability were generally small and inconsistent between cohorts.
• Findings do not support hypotheses that high-fat dairy improves fertility or that lactose/low-fat dairy harms fertility.