A new study from Brazil suggests that fish oil may help lower insulin resistance and improve blood sugar control by reducing inflammation in the body.
The research, published in the journal Nutrients, was conducted on rats that had a condition similar to type 2 diabetes but were not obese. These findings could offer hope for non-obese people with diabetes, who make up 10-20% of all diabetes patients worldwide.
What the Study Found
Scientists at Butantan Institute and Cruzeiro do Sul University tested the effects of omega-3 fatty acids from fish oil on insulin resistance. They gave the rats 2 grams of fish oil per kilogram of body weight three times a week for eight weeks. The fish oil contained two key omega-3 fatty acids:
- EPA (eicosapentaenoic acid) – 540 mg/g
- DHA (docosahexaenoic acid) – 100 mg/g
At the end of the study, the rats showed improved insulin sensitivity, better blood sugar levels, and lower inflammation. Their cholesterol and triglyceride levels also improved, with reductions in total cholesterol and LDL (“bad cholesterol”).
Why This Matters
Type 2 diabetes occurs when the body becomes resistant to insulin, meaning it struggles to regulate blood sugar levels. In most cases, this is linked to obesity, where excess fat triggers chronic inflammation that disrupts insulin function. However, some people develop type 2 diabetes without being overweight, and the cause of their insulin resistance is less understood.
The study used Goto-Kakizaki (GK) rats, which are a well-known model for non-obese diabetes. Researchers discovered that insulin resistance in these rats was linked to an imbalance in immune system cells called lymphocytes.
Normally, these cells help control inflammation, but in these rats, they were in a pro-inflammatory state, similar to what happens in obese individuals with diabetes.
When the rats were given fish oil, their immune cells changed from a pro-inflammatory state to an anti-inflammatory state, reducing insulin resistance. The researchers believe that this shift in immune response may be the key to improving blood sugar control in non-obese diabetes patients.
Inflammation and Insulin Resistance
Previous research has shown that obesity leads to low-grade chronic inflammation, which interferes with insulin signaling. Fat tissue releases pro-inflammatory molecules, which contribute to insulin resistance in overweight individuals. However, in non-obese diabetes patients, inflammation is still present but may come from different sources, such as:
- Genetics – Some people may have a genetic tendency for insulin resistance.
- Gut Health – Other research suggests that slower digestion and delayed intestinal transit may also play a role in non-obese diabetes.
Fish Oil’s Anti-Inflammatory Effects
The study found that fish oil supplementation helped reverse early signs of inflammation in non-obese rats with diabetes.
In younger rats, researchers saw a drop in anti-inflammatory immune cells (Tregs) at just 21 days old, suggesting that inflammation starts very early in life for these animals. Fish oil helped increase Tregs and decrease harmful immune cells like Th1 and Th17, which are known to promote inflammation.
By restoring a healthy balance in the immune system, fish oil appeared to reduce insulin resistance, helping the body respond better to insulin.
What’s Next?
While these findings are promising, more human studies are needed to confirm whether omega-3 supplements can have the same effect in non-obese people with type 2 diabetes. Researchers need to determine:
- The right dosage of omega-3 for humans
- Which type of omega-3 is most effective
- How long supplementation is needed for lasting benefits
Dr. Rui Curi, one of the study’s lead researchers, emphasized that while the results are encouraging, they are still based on animal studies. Clinical trials in humans will be needed before doctors can recommend fish oil as a treatment for insulin resistance in non-obese individuals.
Conclusion
This study suggests that fish oil could be a potential treatment for insulin resistance in non-obese individuals with type 2 diabetes. By reducing inflammation and restoring immune balance, omega-3 fatty acids may help improve blood sugar control and reduce the risk of complications.
However, more research is needed to confirm these effects in humans. If future studies support these findings, omega-3 supplements could become a low-cost and widely available option for managing non-obese diabetes.
The research findings can be found in Nutrients.
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