High-Dose Fish Oil in Women with Obesity: Short-Term Metabolic Boost, Longer-Lasting Anti-Inflammatory Effect

This small study looked at 12 women with obesity and 12 lean healthy women who took a high dose of fish oil (4.8 grams per day, providing 3.2g EPA and 1.6g DHA) for three months, followed by one month with no supplement. Researchers tracked blood markers related to blood sugar control, cholesterol, and inflammation, as well as activity levels of genes involved in immune cell signaling.

During the three months of supplementation, none of the participants changed their weight or body composition. However, several markers improved, including insulin levels, insulin resistance (HOMA-IR), triglycerides, the triglyceride-to-HDL ratio, and the arachidonic acid-to-EPA ratio. Levels of the inflammatory protein TNF-alpha also dropped, along with gene activity linked to several types of immune T-cells involved in inflammation.

After supplementation stopped for one month, the picture changed: insulin, insulin resistance, and the immune-cell gene activity remained lower than baseline, but the other metabolic markers (triglycerides, cholesterol ratios, TNF-alpha) returned to their pre-supplement levels. This suggests that the effects on inflammation-related gene activity may last longer than the effects on blood fat and lipid markers once supplementation is stopped.