Anti-inflammatory diets connected to increased fecundability

Higher-quality diets, including those lower in inflammatory effects, were linked to greater fecundability in prospective preconception cohort studies from North America and Denmark.

The findings were recently published in the American Journal of Clinical Nutrition.

Sydney K. Willis, MSPH, PhD, of the department of epidemiology at Boston University School of Public Health, and colleagues wrote that “diet is increasingly recognized as an important determinant of human fertility,” but it is also “a complex and multifaceted lifestyle factor dictated by economic, geographic, political, cultural, social, and psychological drivers.”

Although other studies have looked at associations with specific foods or nutrients relating to fecundability, the researchers wrote that “it is difficult to translate these findings into dietary guidelines or behavioral advice for couples trying to conceive.” So, the researchers evaluated associations between fecundability and four dietary patterns: alternative Mediterranean Diet (aMed), Healthy Eating Index-2010 (HEI-2010), Danish dietary Guidelines (DDGI) and Dietary Inflammatory Index (DII).

The researchers focused on two preconception cohorts of couples trying to conceive: Pregnancy Study Online (PRESTO) in North America and SnartForaeldre.dk (SF) in Denmark.

They analyzed data from 3,429 SF and 5,803 PRESTO participants who completed a baseline questionnaire on lifestyle and sociodemographic factors then a validated, cohort-specific food frequency questionnaire, which was used to calculate adherence to the dietary patterns.

The researchers found that just over 50% of PRESTO and nearly 75% of SF participants conceived within six attempted cycles.

In both the SF and PRESTO cohorts, greater DII — a less anti-inflammatory diet and indicator of poorer diet quality — was associated with diminished fecundability compared with a more anti-inflammatory diet (fecundability ratio in SF group = 0.83; 95% CI, 0.71-0.97; fecundability ratio in PRESTO group = 0.82; 95% CI: 0.73-0.93).

These results, the researchers wrote, suggest “diets with anti-inflammatory properties may be important for improving fecundability.”

The researchers also noted that “those with greatest DDGI adherence had greater fecundability” in the SF cohort, and adherence to HEI-2010 was associated with greater fecundability in the PRESTO cohort.

In the PRESTO cohort, the HEI-2010 and aMED diets showed the strongest correlations (r = 0.77), followed by DII and HEI-2010 (r = -0.55) and DII and aMED (r = -0.46). In the SF cohort, on the other hand, the DDGI and aMED dietary patterns were most strongly linked to fecundability (r = 0.71), followed by DII and aMED (r = -0.68) and DDGI and DII (r = -0.63).

“In conclusion ... we observed that higher quality diet was associated with greater fecundability, and diets higher in anti-inflammatory properties were associated with greater fecundability, especially among women with overweight or obesity,” Willis and colleagues wrote. “These data provide additional evidence that inflammation may contribute to the association between diet quality and fecundability.”

Future research, they wrote, “should consider dietary patterns unique to the preconception window that may be associated with fecundability.”

“Examining and identifying relevant dietary patterns, as opposed to nutrients or food groups, provides useful information that can inform policy recommendations,” they wrote.