Quick Facts

• Weekly sardine consumption reduced diabetes risk from 37% to 8% in high-risk adults over one year
• Participants ate two cans of sardines per week as part of a structured nutrition program
• Sardines are environmentally sustainable with low greenhouse gas emissions compared to other protein sources

A new study published in Clinical Nutrition found that eating sardines twice weekly can dramatically reduce diabetes risk in older adults with prediabetes.

Researchers from Barcelona’s Hospital Clínic followed 152 patients aged 65 and older with prediabetes for one year. Half the participants added 200 grams of sardines to their weekly diet while maintaining a diabetes prevention nutrition plan.

The results were striking. In the sardine group, diabetes risk dropped from 37% to just 8%. The control group saw only a modest decline from 27% to 22%.

“The consumption of sardines is not only affordable in economic terms and easy to source, but it is safe and preventive against type 2 diabetes,” said lead researcher Dr. Diana Díaz Rizzolo. “This is a major scientific discovery.”

Participants were encouraged to eat the sardines whole, including bones, to maximize nutritional benefits. The fish provided key nutrients including omega-3 fatty acids, taurine, calcium and vitamin D.

The sardine group also showed improvements in cholesterol levels, blood pressure, insulin resistance and sugar metabolism hormones compared to the control group.

Sardines rank among the most sustainable protein sources, producing greenhouse gas emissions comparable to nuts and seeds rather than larger fish.

Diabetes affects 830 million people globally as of 2022, up from 200 million in 1990. The condition causes 3.4 million deaths annually and costs $1.015 trillion in healthcare spending.

Researchers are now studying how sardines affect gut bacteria and inflammation, both linked to diabetes development. The team emphasizes that whole sardines work better than isolated nutrient supplements due to nutrient synergy.

The findings offer a practical diabetes prevention strategy using an affordable, widely available food source. Two cans of sardines per week cost less than $5 and require no special preparation.

Read more: Research Finds This Sustainable Food Source May Help Prevent Diabetes