In the news: Omega-3s Tied to Less DR in T1 Diabetes; Med Diet & Obesity Linked Cancers

In T1D, Omega-3 Intake Linked to Less Diabetic Retinopathy & a Better Perfused Macula

Diabetic retinopathy (DR) is the leading cause of blindness in type 1 diabetics. The retina is rich in long chain omega-3 fatty acids, particularly DHA. Once these fatty acids are released from cell membranes, they form oxylipins that are protective of vessels, including micro-vessels.

Since the amount of omega-3 in cell membranes depends on dietary intake of these fatty acids (primarily from fatty fish), omega-3 consumption is thought to be protective against DR. However, information about omega-3 intake and its role in DR is scarce in type 1 and limited to type 2 diabetes.

To learn more, a research team from Spain and the USA collaborated to examine the relationship between blood biomarkers of marine omega-3, diabetic retinopathy, and retinal microvascular data obtained through OCTA(1).

Baseline data was obtained from 188 consecutive type 1 diabetic patients and 88 controls. Blood levels of EPA, DHA and DPA was determined, and ocular data included DR grading. OCTA scans were used to obtain macular vessel density and perfusion density, foveal avascular zone area, perimeter and circularity.

Patients with type 1 – no matter what stage of DR – had significantly lower blood levels of EPA, DHA, DPA and EPA + DHA compared to non-diabetic controls (p<0.001 in all cases).

In patients with type1, higher EPA was linked with a lower prevalence of DR. Increasing proportions of DPA, DHA, EPA +DHA, and total marine omega-3 fatty acids were associated with higher vessel and perfusion densities in the macula (p values from 0.001 to 0.05).

The authors conclude that in type 1 diabetics, higher blood omega-3 status is related to lower grades of diabetic retinopathy and preserved retinal perfusion – the delivery of blood and oxygen to the retina.

The results of this study are consistent with the current model of how diabetic retinopathy develops and with data from experimental models. The findings add to the idea that marine omega-3 fatty acids are a healthy fat in type 1 diabetes.

‘Med’ Diet Lowers Risk of Obesity Related Cancers

Obesity is a known risk factor for certain cancers including colorectal, endometrial, breast, kidney, gallbladder, pancreatic, ovarian, liver and others. How obesity raises the risk of these cancers isn’t fully understood, but factors such as chronic inflammation, hormonal changes and production of certain growth factors are thought to play a role.

To examine the relationship between the Med diet and these cancers(2), researchers analyzed data from over 450,000 participants in the EPIC study, which included 23 centers in 10 countries. Participants were followed for a median 14.9 years. Diets were assessed and scored on a 9-point scale for adherence to the Med diet. Scores were categorized as low (0-3 points), medium (4-6 points) and high (7-9 points).

Among participants, 4.9% experienced an obesity related cancer. Measured in person-year, the rates for obesity-linked cancers were 0.053, 0.049, and 0.043 in the low, medium, and high Med groups, respectively.

Overall, those who followed the Med diet most closely had a 6%, modestly lower risk compared to those with the least adherence. Even a medium adherence was associated with a small reduction in the risk of these specific cancers.

Looking at site-specific cancers, higher Med diet adherence was linked with an 8% lower risk of colorectal cancer, a 48 % lower risk of hepatocellular cancer and a 33% lower risk of kidney cancer. More research is needed to better understand how the Med diet might be working to potentially reduce cancer risk.

References

1. Sala-Vila, A et al. Blood omega-3 biomarkers, diabetic retinopathy and retinal vessel status in patients with type 1 diabetes. Eye. Published online Feb. 18, 2025.
2. Aguilera-Buenosvinos I, et al. Adherence to the Mediterranean diet and obesity-linked cancer risk in EPIC. JAMA Open Network. Published online Feb. 25, 2025.