Calanus Oil and Lifestyle Interventions Improve Glucose Homeostasis in Obese Subjects with Insulin Resistance

Obesity increases the risk for insulin resistance (IR) and type-2 diabetes. Lifestyle interventions (LI) and dietary supplementation can help mitigate IR. We investigated the effect of calanus oil (CO) supplementation, combined with LI, on glucose homeostasis in obese subjects. CO, a novel marine oil, contains omega-3 fatty acid wax esters as well as plant sterols and astaxanthin. In the double-blind, randomized, placebo-controlled 12-week intervention study, 266 subjects with distinct IR phenotypes were assigned to four groups: 2 g CO/day, 4 g CO/day, 2 g CO/day + LI, and placebo. The effect of CO on HOMA index reduction was influenced by the initial (t₀) squared HOMA index (interaction <i>p</i> = 0.011). A post hoc test showed significant improvement with 2 g CO/day + LI (estimated marginal means [EMM] 95% confidence interval [CI]: -0.19 [-0.80-0.41], <i>p</i> = 0.021). Secondary analysis revealed that 4 g CO/day had significant effects in subjects with mild IR (HOMA index 2.5-5.0) (EMM [95% CI]: -0.76 [-1.53-0.03], <i>p</i> = 0.043). CO supplementation improved glucose homeostasis, with effects varying by dose, combination with LI, and IR phenotype.