Higher intake of the lignan secoisolariciresinol was found to reduce the risk of type 2 diabetes, particularly among patients with obesity and premenopausal women, according to a new cohort study.
Lignans, phytoestrogens prevalent in foods such as flaxseeds, whole grains, and coffee, have been associated with various health outcomes, including a reduced risk of T2D.
In the study, published in JAMA Network Open, investigators assessed the association between lignan intake and type 2 diabetes (T2D) incidence in 201,111 U.S. men and women over 5 million person-years of follow-up.
The study participants had an average age of 44.7 years (standard deviation = 10.1 years). Most of the cohort was female, comprising 80.2% (n = 161,169). In terms of racial and ethnic composition, the participants included 1.3% Black patients, 0.8% Asian patients, 1.2% Hispanic or other racial/ethnic group patients, and 96.7% White patients.
During the follow-up period totaling 5.1 million person-years, 20,291 new cases of T2D were identified. The study's multivariable-adjusted analysis showed the following hazard ratios (HR) when comparing the highest to the lowest quintiles of intake: 0.87 (95% confidence interval [CI] = 0.83–0.91) for total lignans, 0.72 (95% CI = 0.69–0.76) for secoisolariciresinol, 0.92 (95% CI = 0.87–0.96) for pinoresinol, 0.93 (95% CI = 0.89–0.98) for matairesinol, and 0.99 (95% CI = 0.94–1.04) for lariciresinol.
In the subgroup analyses, participants with obesity (body mass index ≥ 30) had an HR of 0.75 (95% CI = 0.71–0.79) for T2D when comparing the highest and lowest intakes of secoisolariciresinol. For premenopausal women, the HR was 0.67 (95% CI = 0.65–0.69) for the same comparison. The interaction analysis revealed significant interactions between secoisolariciresinol intake and both obesity status (P < .001) and premenopausal status (P = .003).
The study findings indicated that higher total lignan intake, except for lariciresinol, may be associated with a lower risk of developing T2D. Among individual lignans, secoisolariciresinol exhibited a more pronounced inverse association with T2D, particularly in participants with obesity and premenopausal women. The study observed a risk reduction among those with the highest intake of secoisolariciresinol in these subgroups.
Additionally, a validation study demonstrated that increased lignan intake correlated with lower HbA1c levels and improved lipid profiles. Lignan intake, as measured by 7-day diet records, was linked to reduced HbA1c levels, with percentage changes varying between –0.92% and −1.50%. Lignan intake was also associated with decreased C-reactive protein levels and better lipid profiles, characterized by lower triglycerides and higher high-density lipoprotein cholesterol.
These results suggest that incorporating lignan-rich foods into the diet may be beneficial for T2D prevention. The study underscored the need for further research to elucidate the mechanisms underlying these associations and to inform dietary guidelines aimed at preventing T2D.
The study was funded by grants from the National Institutes of Health, with no reported conflicts of interest.
