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Omega-3 supplements fail to reduce body weight, insulin resistance in adolescents with obesity

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January 7, 2019

Combined with a hypocaloric diet, an omega-3 fatty acid supplement failed to improve measures of insulin resistance and body weight in children with obesity over 3 months, according to findings from a randomized controlled trial published in Pediatric Obesity.

Mardia López-Alarcón, MD, PhD, a researcher in the unit of research in medical nutrition at the Mexican Institute of Social Security in Mexico City, and colleagues analyzed data from 366 adolescents with obesity recruited between July 2012 and December 2015 from three family medicine clinics (mean age, 14 years). Researchers randomly assigned participants to a combination of 800 mg eicosapentaenoic acid plus 400 mg docosahexaenoic acid (n = 183) or 1 g sunflower oil (n = 183) as placebo daily for 3 months; both groups were also assigned to an energy-restricted diet (700 kcal reduction). Children provided blood samples at baseline and 3 months and attended monthly exams to assess body weight, dietary information and blood pressure. Researchers measured fasting insulin and insulin resistance via homeostatic model assessment of insulin resistance (HOMA-IR). Researchers used linear regression analysis to assess the influence of omega-3 supplementation on weight, insulin and HOMA-IR.

Within the cohort, 92% of children had insulin resistance at baseline, 28% had hypertension, 6% had prediabetes, 66% had hypertriglyceridemia and 21% had low HDL cholesterol.

At 3 months, the mean decrease in BMI z score was similar for the omega-3 and placebo groups (–0.64 vs. –0.75, respectively; P = .777), as were mean decreases in fasting insulin (–2.3 µU/mL vs. –2.3 µU/mL, respectively; P = .496) and HOMA-IR (–0.62 vs. –0.63, respectively; P = .516). Results persisted after adjustment for corresponding baseline values, according to researchers.

“It is important to clarify that our results do not discount previous findings of the preventive effect of [omega-3 supplementation] in healthy children or adolescents, because we studied an unhealthy sample,” the researchers wrote. “Consequently, our results are not contrary to the reported protective role, but instead, they show that there is no therapeutic effect. This finding is in line with those of others obtained from intervention studies that failed to demonstrate the benefits of [omega-3 supplementation] in individuals with diabetes or insulin resistance.”

The researchers also noted that preliminary analysis of secondary outcomes in the study suggests that omega-3 supplementation may prevent progression to insulin resistance in children with obesity who have not already developed the condition; however, further research is needed to support the finding. – by Regina Schaffer

Disclosures: The authors report no relevant financial disclosures.

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