Lignans may protect against T2D

Men and women with long-term consumption of lignans, phytoestrogens abundant in Western diets, are at lower risk of type 2 diabetes (T2D), and this is especially true for those with obesity and women who are premenopausal, according to a study.

For the study, researchers identified a total of 201,111 participants (mean age 44.7 years, 80.2 percent female, 96.7 percent White) from the Nurses’ Health Study (NHS, 1984-2018), NHSII (1991-2019), and Health Professionals Follow-Up Study (HPFS, 1986-2020). All participants were free of T2D, cardiovascular disease, and cancer at baseline.

A validated food frequency questionnaire, which was updated every 2 to 4 years, was used to assess total and individual lignans. In a separate cohort of 496 participants from the Men’s Lifestyle Validation Study (MLVS), lignan intake was measured using two sets of 7-day diet records (7DDRs).

A total of 20,291 incident cases of T2D were recorded over 5,068,689 person-years. Median total lignan intake for the highest quintile was 355.1 μg/d in NHS and 459.9 μg/d in HPFS at the median follow-up time.

Higher lignan intake, except for lariciresinol, was associated with reduced T2D risk. Compared with the lowest quintile of intake, the highest quintile was associated with a 13-percent risk reduction (hazard ratio [HR], 0.87) for total lignans, 28-percent risk reduction (HR, 0.72) for secoisolariciresinol, 8-percent risk reduction (HR, 0.92) for pinoresinol, and 7-percent risk reduction (HR, 0.93) for matairesinol.

Of note, secoisolariciresinol intake was associated with a significant reduction in T2D risk among individuals with obesity (BMI ≥30 kg/m²: HR, 0.75; BMI <25 kg/m²: HR, 0.82; p<0.001 for interaction) and premenopausal women (premenopausal women: HR, 0.67; those with history of hormone use: HR, 0.82; p=0.003 for interaction).

Finally, dietary lignan as evaluated with 7DDRs was associated with lower HbA1c levels (percentage change: from −0.92 percent to 1.50 percent), in addition to lower C-reactive protein levels and better lipid profiles.