Reviewing a total of 17 studies — featuring 672 participants above the age of 18 — the researchers found in their subgroup analysis that fish oil supplementation could heighten insulin sensitivity in those experiencing at least one symptom of a metabolic disorder.
However, the same benefits were not observed in healthy people or those who already had type 2 diabetes.
Those who had metabolic disorders but not type 2 diabetes experienced up to a 47% decrease in insulin resistance when supplemented with fish oil in the short term.
Writing in the journal Lipids in Health and Disease, researchers stated: “The results of the subgroup analysis showed an association of lower risk in the group of people with metabolic disorders.
“We found fish oil had no effects on insulin sensitivity among the healthy people or people with T2DM. Also, subgroup analysis showed a positive effect of fish oil on insulin sensitivity among the short-term intervention group rather than the long-term intervention group.”
Duration is key
Because serum omega-3 polyunsaturated fatty acid levels require a minimum of four weeks to reach equilibrium, the review suggested that the ideal intervention period should be less than 12 weeks but at least more than four weeks.
This led the analysis to state that fish oil supplementation could be a “significant intervention as secondary prevention” for metabolic syndrome and type 2 diabetes. However, it also added that duration, not dosage, was crucial for such intervention to be effective, as the reviewed studies found that the supplementation dosage had no impact on insulin sensitivity.
The analysis concluded that the results had strong implications for the prevention of type 2 diabetes.
“Taken together, these findings have great implications for prevention of T2DM. The research studies in the future would be more beneficial to explicitly prescribe interventions for trials, especially the dose, frequency, administration and duration of fish oil supplementation. Additionally, more research should be done to determine the population who could benefit from the intervention,” the paper concluded.
Source: Lipids in Health and Disease
“Fish oil supplementation and insulin sensitivity: a systematic review and meta-analysis”
Authors: Huanqing Gao, et al.