March 9, 2025, 2:17 pm | Read time: 3 minutes
The treatment of type 2 diabetes requires a change in diet and other lifestyle habits, and medication is also often used. A study has now investigated the possible effect of a dietary supplement with omega-3 fatty acids in the form of fish oil capsules — with optimistic results.
Omega-3 fatty acids are known to have a positive effect on various health-related areas. FITBOOK recently reported on a study suggesting that omega-3 supplements can slow down biological aging processes.1 Part of the effect is attributed to the anti-inflammatory effect of omega-3. Researchers have now investigated this for its potential in diabetes.
Overview
How Do Omega-3 Fatty Acids Affect Diabetes?
Fish oil has long been considered potentially preventative against diabetes. A study from 2021 showed that the consumption of oil sardines could reduce the risk of developing diabetes in prediabetic people by around 70 percent.2 For clarification, in prediabetes, blood sugar levels are elevated, but a diabetes diagnosis has not yet been made.
A more recent study from Brazil has now investigated how fish oil affects insulin resistance.3 This condition, in which the cells react less to insulin and the blood sugar level rises, is an important risk factor for the development of diabetes.
Details of the Study
The study aimed to determine the effects of omega-3 fatty acids on inflammation and blood sugar regulation in cases of insulin resistance. To this end, Goto-Kakizaki rats (GK) were used — a specially bred rat line that develops insulin resistance and type 2 diabetes due to a genetic modification. These rats show typical human characteristics of diabetes without being obese.
Obesity is often associated with chronic inflammation, explains study author Rui Curi in a press release.4 This is because adipose tissue — especially visceral fat — releases pro-inflammatory hormones and cytokines. Although visceral fat, which normally fuels inflammation, is absent in Goto-Kakizaki rats, systemic inflammation remains. This makes it possible to compare the inflammatory processes with those in humans.
Procedure
For the study, the researchers administered omega-3 fatty acids to the rats three times a week over a period of eight weeks. Specifically, the animals were given two grams of fish oil per kilogram of body weight. The scientists then determined possible changes in inflammatory markers in the lymphocytes of the test rats, i.e., in the immune cells. The researchers also used special tests to determine whether their ability to process glucose had improved. An insulin tolerance test (ITT) also showed the cells’ reaction to insulin.
Results and Significance
“We found that the animals’ insulin resistance could be reduced by modulating the inflammatory response,” said Curi in the press release. Treatment with omega-3 fatty acids influenced the inflammatory response in the rats’ bodies. The profile of the immune cells changed from a pro-inflammatory to an anti-inflammatory state.
Omega-3 fatty acids are known to be found in various foods, including plant-based foods such as nuts and various oils. However, according to Curi, the types eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in particular, which are contained in high quantities in fish oil, can reduce existing insulin resistance and also improve blood sugar, inflammation, and blood lipid levels. In this way, omega-3 fatty acids could also be helpful for diabetes.
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Limitations
The study’s significance is somewhat limited by its relatively brief duration. The authors point out that the results are based on isolated T lymphocytes and not on specific subgroups of these cells. This means that the analysis does not go into depth: no specific cell types that could be responsible for certain immune reactions were examined. In addition, only insulin-resistant test subjects without diagnosed diabetes were examined, which limits the transferability of the results — especially as the modulation has only been carried out in animal experiments to date.